Film Critique of the Upper Extremity - Part 1: Shoulder, Clavicle, and Humerus


Critique of the Shoulder, Clavicle, and Humerus radiographs

Author: Nicholas Joseph Jr. RT(R)(CT) B.S. M.S

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Instructions:

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Objectives:

Upon completion, the reader should be able to:

  • Identify the anatomy of the shoulder on diagrams and radiographs.
  • State the diagnostic criteria for the AP shoulder views including internal and external rotation of the humerus.
  • State the proper positioning of the humerus for the AP views of the shoulder and tell what each view demonstrates.
  • Discuss the importance of proper imaging to demonstrate anterior or posterior dislocations of the shoulder joint.
  • State how to properly reposition for improperly made radiographs of the shoulder.
  • Describe the anatomical structure called the scapula “Y” by stating what structures form the arms and leg of the “Y.”
  • State the diagnostic criteria for the scapular “Y” projection of the shoulder.
  • List what structures are demonstrated on a properly taken scapular “Y” projection.
  • State the diagnostic criteria for the craniocaudal projection of the shoulder.
  • List what structures are demonstrated on a properly taken craniocaudal projection.
  • Explain how the CR is adjusted when the patient cannot abduct the arm to 90 degrees for the craniocaudal projection.
  • Discus what soft tissue structures should be visualized when the radiographic exposure for the AP shoulder views is optimal.
  • Explain why a suspected proximal humerus fracture should be handled carefully to avoid possible injury to the neurovascular bundle of the axilla.
  • List and discuss the role of the four rotator cuff muscles.
  • State the purpose of the Grashey projection and discuss how the patient is positioned for it.
  • State what should be done to correct radiographs of the shoulder using the diagnostic criteria for each projection.


Article Navigation:

Introduction

Anatomy of the Shoulder and Proximal Humerus

Diagnostic Criteria for Imaging the AP Views of the Shoulder

Diagnostic Criteria for the Axillary view a.k.a. Craniocaudal Projection

Diagnostic Criteria for the Scapular "Y" View

Diagnostic Criteria for the AP and Lateral views of the Humerus

Test



imageShoulder-10

Introduction

Radiologic technologists make and review hundreds of thousands of films daily as part of our routine job performance. Acquiring an acceptable radiograph or digital image requires knowledge of the anatomy, positioning criteria, radiographic exposure, and other skills. In addition the radiographer must know and meet specific diagnostic imaging criteria in order to provide the radiologists images suitable for interpretation. A knowledgeable radiographer assesses acquired images as a point of quality control to make sure it meets the diagnostic criteria. No radiographer wants to pass on poorly made radiographs to the radiologist but when hundreds of images are taken daily it is easy to slack and become complacent. Achieving high quality diagnostic images when hundreds of different images are taken each day requires a conscious effort to maintain quality. Besides, we can go from imaging the hand to imaging the foot to imaging the abdomen in a matter of minutes. Not to mention the patient has a role in how images are acquired and their cooperation may vary from extremely cooperative to belligerently uncooperative. Yet the responsibility for achieving a high quality diagnostic image remains with the radiographer. Combining imaging skills with patient skills is truly an artful use of scientific principles and people skills. Occasionally the radiographers must be creative in order to present anatomy that meets the diagnostic criteria. For example, a patient who presents with extreme scoliosis needing a shoulder radiograph may require a creative approach to imaging.

Knowing what is to be included in each view and the proper radiographic exposure technique for optimal subject detail is a must for any discussion on image critique. As we view images contained in this module we will also address two important issues: what anatomy should be presented in a specific view, and how should that anatomy be presented. The discussions will also include critique of the radiographic technique. For example a radiograph that is positioned correctly and has the specified anatomy presented must also have optimal exposure technique to get the maximum diagnostic value. The diagnostic criteria for each view in our critique series is given; however, these should already be committed to practice, as this is actually a review of the current practice of radiography. The intent of this learning module is to reaffirm that our imaging practices conform to the achievement of specific diagnostic criteria. It is commonly thought that radiographers just put the part on a cassette and shoot the picture, which is far from the truth of how we acquire diagnostic images. Often we are too busy in school to go beyond what the textbook teaches, for example, an AP shoulder view may reference the positioning of the part and the point of entrance of the central ray (CR) and degree of tube angle. You may have skipped the discussion on film critique because your study time was limited. Now you can take your time and focus on each radiograph you commonly image and review its diagnostic criteria.

You will notice that this critique takes a simple approach to viewing radiographic images. First the anatomy of each part is reviewed, and then the diagnostic criteria for the view under discussion are given. This is the template for discussion of each image. By knowing the diagnostic criteria you can compare each radiograph and ask, “Did this radiograph meet the diagnostic criteria?” When a radiograph does not meet the diagnostic criteria then you must decide if it should be repeated or not. Keep in mind that just because a radiograph does not meet the entire diagnostic criteria does not mean it must always be repeated. Sometimes diagnostic criteria are met using a series of images for a particular view. So consider this film critique relative to patient presentation and additional views that may be necessary to complete any diagnostic criteria. An image is presented for you to critique, and then the author using the stated diagnostic criteria as a reference presents a discussion. You should jot down your own critique of each image before reading the review in this way you will improve your critique skill. You should discuss what should be done to correct an unsatisfactory image include positioning, anatomy, and radiographic exposure technique. Hopefully this will become a pattern for you as you review your images before presenting them for a diagnostic reading.

Radiographic technique and patient cooperation are very important factors that effect image quality. Likewise, not all images that are eye pleasing when casually viewing are diagnostic to the keen eye of a radiologist. Radiographers must combine their knowledge of diagnostic criteria and a sharp eye for viewing mages for diagnostic quality. Paramount to viewing is the production of quality images time after time no matter how the patient presents. The most important point of film critique is to acquire quality radiographs even in the most difficult circumstances. While most patients cooperate for imaging procedures there are times when a patient is too young to understand and cooperate, or the manifestation of alcohol use is a factor, or even a language barrier can hinder instructions to the patient and may diminish cooperativeness. Yet no specific circumstance inherently lowers or raises the bar for malfeasance or nonfeasance that haunts poor imaging. Often with today's shortages of radiologic technologists inexperienced radiographers are set on their own to clear images for interpretation without the precious benefit of critique by a seasoned professional technologist. Furthermore, in order to evaluate any radiograph for technical excellence a solid foundation in how the four radiographic densities interplay when a set of exposure factors are selected.

A good exposure technique must provide adequate density and good subject contrast that maximizes the visualization of bone, muscle, fat and air. Balancing these densities require a good understanding of how exposure factors like milliamperage (mA), kilovoltage (kVp), source-to-image distance (SID), object-to-image distance (OID), use of grids, and patient body habitus and tissue make-up interplay. Bone is the most radiopaque of the four radiographic densities. Air is a radiolucent density, which is dark on a radiograph. Between these two are muscle and fat densities that complete the viewing spectrum. Together these four radiographic densities create a mosaic of gray tones that create subject contrast and background density. A fifth density, metal, may be a part of the radiograph in the form of a prosthetic implant.

When present, metal also contributes to subject contrast. Metal is more radiopaque than bone and is the main component of implanted prosthetic devices. Metal is used extensively in radiology to enhance subject detail. Special formulations of iodine and barium are used in radiographic contrast agents and are the opacifying moiety in these materials. Using a contrast agent such as barium sulfate or iodine solutions allow us to demonstrate information about some structures better than if without it. For example, anatomical detail in the alimentary tract can be seen. Distinction of pathology in the esophagus, stomach and colon are best seen using barium sulfate or oral iodinated media. Blood vessels, liver, kidneys, spleen, pancreas, and such are best demonstrated using intravenous iodine radiopaque contrast agents. Intrathecal administration of water-soluble contrast agent can demonstrate the subarachnoid space of the brain and menenges. Altering subject detail is necessary to enhance the diagnostic value of many radiology studies. As technologists, we are able to use radiographic technique selection to enhance the display of many structures with or without using contrast agents.

Evaluating radiographic density, subject contrast, image detail, and anatomical presentation of each radiograph is part of film critique. Prior to submitting a radiograph for interpretation the technologist should evaluate the subject contrast. Bone, muscle, fat, and air should be well balanced within the subject and a good background density should be present. As we present many radiographs in this module it is our goal to improve your ability to evaluate radiographs prior to submitting them for interpretation. It is our hope that you critique films in a way that encourages perfection at using the diagnostic criteria's, which are the standards by which we image. We also image using the standard practice of ALARA (as low as reasonably achievable) in administering radiation for diagnostic purposes. Therefore, the purpose of this critique is to instill the principle of meeting the diagnostic criteria with the first radiograph. Reducing radiation dose without compromising diagnostic quality is also a primary goal.

Radiographs of the shoulder are commonly taken, so the radiographer should be very familiar with its anatomy, positioning, and proper exposure technique. When a request is made to take a shoulder x-ray the radiograph should include the proximal humerus, mid to lateral portion of the clavicle, and most of the superior scapula. The routine shoulder radiograph is not intended to include all of the scapula, or the medial end of the clavicle and sternoclavicular joints. Routine shoulder radiographs are usually taken to evaluate the rotation of the humerus or chronic bone pathologies of the shoulder joint. So most textbooks do not specify the field of view for imaging for routine vs. trauma imaging of the shoulder in which the entire scapula and clavicle are included. So the radiographer must distinguish routine imaging of the shoulder from trauma imaging of the shoulder. For trauma imaging of the shoulder we must include the entire clavicle, entire scapula and the proximal humerus. Especially when the patient is immobilized and on spine precautions and suffers multiple injuries like to the chest, abdomen and extremities. We should expand our diagnostic imaging field of view for trauma so the entire clavicle and scapula as well as the medial and lateral rib margins are demonstrated. So our diagnostic criteria for imaging also changes when we consider whether the patient has undergone traumatic event, or is suffering a chronic condition like pain or loss of mobility.

Because most radiographers regard the shoulder as an uncomplicated structure anatomically it may not get the attention to diagnostic criteria it deserves. Hopefully we will change this point of view (if you have it) by the time you have completed this module. The shoulder is not a simple joint; in fact it has more extensive motions than any other in the body. Besides, its relationship to the upper limb is unquestionably important and does present challenging diagnostic pitfalls the technologist must help the radiologist overcome through quality imaging. Some of the pitfalls are partial acromioclavicular (AC) joint separation, direct posterior dislocation of the glenohumeral joint, or even fracture of the coracoid process. Complete disruption of the acromioclavicular fibrous bridge does not always demonstrate a separated joint, like when the coracoclavicular ligament is intact. The joint may need to be stressed using erect weight bearing views to fully appreciate this type of dislocation. Certain fractures of the coracoid process are established only when the joint space is profiled, or on the Axillary projection. For these and other reasons additional views of the shoulder to accompany the standard AP views along with correct positioning and most favorable exposure technique is required for optimal diagnostic potential.

We use a common terminology to describe exposure technique, positioning, and tube angle descriptions. The term overexposure is used to describe a dark radiograph. The cause being too many photons has exposed the image due to excessive milliamperage/time (mAs). Underexposed is the opposite principle in which insufficient photons exposed the radiograph and the mAs should be increased. The term underpenetrated refers to not enough energy in the photons to penetrate the part. This is directly controlled by the kilovoltage selected (kVp). An underpenetrated radiograph can be corrected by increasing the kVp. Likewise, an overpenetrated image can be compensated for by decreasing the kVp. We use the term positioning error to mean the patient or part is incorrectly aligned by radiological standards. Tube error is a term that can mean improper entry of the central ray (CR), improper tube angle, or improper direction of the tube, e.g. vertical beam should be horizontal. These terms should not be confusing since they are commonly used in radiology literature.

This lesson is organized so that you can review the anatomy and positioning of the common views of the upper extremity. Then images are presented for you to critique using the established diagnostic criteria for each view. The author's critique of each image is presented for you to compare your notes. The goal is to promote effective learning. So use a pencil and a writing pad to jot down your critique of each image prior to reading the authors critique. Compare your notes and see how accurately you are critiquing each radiograph. Obviously only the main points of critique are presented as you may have other observations worth mentioning above the author’s notes. Upon completion you may take brief generalized examination, which presents questions from samples of the images in this module.

Anatomy of the Shoulder and Proximal Humerus

Shoulder injuries occur frequently from automobile accidents, sports activities, work related injuries and so forth. Chronic pain is also an indicator that frequently requires radiographic imaging. In order to properly image the shoulder a radiographer must be familiar with basic shoulder anatomy and how to position the shoulder for correct diagnostic referencing. Good radiographic imaging technique always begins with a solid understanding of the anatomy of the part being demonstrated and its correlation with standard criteria for diagnosis. Anatomy is often a first course in any radiology educational program because it is fundamental to all imaging studies and radiological procedures. In this section we will discuss the basic anatomy of the shoulder relative to plain film imaging. Our purpose is to understand how we should present shoulder anatomy for diagnostic interpretation. Knowledge of radiographic anatomy is the basis of accurate positioning for diagnosis.

The astute student of radiography will ultimately gain knowledge of some of the many normal anatomical variations that can even confound physicians. Sometimes the unwary technologist may be fooled by ossification centers that mimic fractures. Traumatic or chronic pain may cause the technologist to not position the part properly. As a result the radiograph may fail to meet diagnostic imaging standards. Improper positioning can cause overlapping of normal structures or simulate an abnormality. For example, improper external rotation of the humerus during shoulder radiography in children can give the appearance of acromioclavicular separation. Another example often seen with conventional pediatric chest positioning is when the arms are stretched above the head what appears to be a dislocation of the glenohumeral joints when they are not. The point here is poor positioning can simulate pathological findings. Radiologists are aware of positioning gamuts and anatomical variants when interpreting radiographs. However, the role of the technologist is to present radiographs that meet known diagnostic criteria void of ambiguity. One of the primary purposes of this film critique of the upper extremity is to review the diagnostic criteria and assure technologists are able to determine when it has been met for any particular projection. The diagnostic criteria references positioning, anatomy demonstrated, and optimal radiographic exposure and subject contrast.

Let’s begin our discussion with the shoulder girdle, a term referring specifically to the clavicle and scapula. The importance of the shoulder girdle is that it connects the respective upper limb to the trunk. Don’t be fooled by its seemingly simple bone anatomy, as you may know from using your own limb this attachment is very strong. Just think of the work and motions of the shoulder girdle and shoulder joint during simple activities like reaching for a cup, or putting up groceries, or the many motions the shoulder is capable of during sports activities. These complex functions are possible because shoulder girdle firmly attaches the arm to the trunk through a strong articulation at the shoulder joint. The clavicle attaches the shoulder to the axial skeleton at its articulation to the sternum, and posteriorly the scapula is attached to the trunk by strong muscles like the supraspinatus, infraspinatus, subscapularis, and teres major muscle groups. The upper limb is attached to the scapula through its articulation with the head of the humerus at the shoulder joint. The scapula covers a broad portion of the posterior ribs, mainly from about the second rib through the seventh rib.

imageShoulder-01
Attaching the shoulder girdle to the trunk anteriorly is the clavicle at the articulation of the sternoclavicular joint (A). The clavicle also articulates with the scapula laterally at the acromioclavicular joint (B). Notice that the scapula (C) attaches the shoulder to the trunk posteriorly. The upper extremity is then hung on the shoulder girdle at the articulation of the humerus (D) to the scapula.

The clavicle, called the collar bone is classified as a long bone. It has three named parts: laterally its acromial end, the middle portion called the body, and a medial sternal end. It has two articulations, the lateral end joins the acromion process of the scapula to form the acromioclavicular joint (AC joint); the medial end forms a sternoclavicular joint (SC joint) with the sternum. The sternoclavicular joints are prominent and can be felt near the midline of the upper chest. The clavicle joins the manubrium, which has a positioning landmark on its superior surface, called the jugular notch. The jugular notch references the approximate level of the fourth thoracic vertebra. This articulation is important because the sternoclavicular joint is the sole articulation between the upper extremity and the anterior trunk. Surprisingly this joint rarely suffers significant injury, a proof of its fine construction. Only 2-3 percent of pectoral girdle dislocations occur at a sternoclavicular joint.

The sternoclavicular joint when it dislocates can go anterior or posterior with slight superior displacement. Anterior dislocations are 20 times more common than posterior dislocations; however, most complications of sternoclavicular joint dislocations are associated with posterior dislocations. Besides an obvious lump other complications include laceration of the superior vena cava, thoracic outlet syndrome, injury to the laryngeal nerve causing voice change, pneumothorax, esophageal rupture, compression of the trachea, and occlusion of subclavian or carotid arteries. Plain film radiographic evaluation is difficult to achieve, but conventional tomography or CT provides good diagnostic information.

imageShoulder-02
This coronal CT presentation of the sternoclavicular joints (SCJ) demonstrates the anatomy of the sternal end of the clavicle’s attachment to the manubrium (M). The left SC joint (blue arrow) shows a separation of the sternoclavicular joint. An accompanying fracture of the manubrium is seen (white arrow). The SC joint is a cartilaginous attachment between the manubrium and clavicle to allow a gliding type movement. The normal wide normal articulation is demonstrated on the right.

The scapula is a triangular flat bone. Its anterior surface is apposed against the posterior ribs. It is convexed on its anterior surface and concave along its posterior surface. It is described as having three defined borders and three angles where these borders meet. Three structures are found within the superior border: the superior angle (a.k.a. medial angle), the scapular notch, and coracoid process. There are no named anatomical structures in the vertebral and axillary borders. The vertebral (medial) border is towards the spine; the lateral (axillary) border is towards the armpit. Inferiorly at the junction of the vertebral and axillary borders is the inferior angle. Superiomedially the superior and vertebral borders form an angle called the superior angle (a.k.a. medial angle). At the junction of the superior and axillary border a thickened process called the glenoid process is formed. The glenoid process is the lateral angle of the scapula. On the lateral surface of the glenoid process is a rather large fossa called the glenoid cavity. It articulates with the head of the humerus forming the glenohumeral joint.

The anterior scapular surface has a rather large broad shallow fossa called the subscapular fossa; it houses the subscapularis muscle. A thick sharp ridge of bone called the spine of the scapula divides the posterior surface. The area above the scapular spine is formed into a deep fossa called the supraspinatus fossa that houses the supraspinatus muscle. Below the scapular spine is a larger infraspinatus fossa that houses the infraspinatus muscle. These two muscles are part of the rotator cuff muscle group that rotates the humerus. The long scapular spine ends laterally in a prominent irregular structure called the acromion process. The acromion process articulates with the lateral extremity of the clavicle forming the acromioclavicular joint. This is a diarthoses-gliding type joint.

Acromioclavicular joint injuries (12% of shoulder injuries) are more frequent than sternoclavicular joint injuries (2-5% of shoulder injuries), and less common than glenohumeral joint injuries (85% of shoulder injuries). AC joint dislocations occur from a direct fall on the shoulder or high impact injury with an outstretched arm. There are many injuries to the AC joint that require good radiographic positioning to diagnose. Injuries that involve the AC joint may include a fractured coracoid process, detachment of the deltoid and trapezius from the clavicle, or tear of ligament holding the joint together. A normal width of the AC joint is 7mm in men and 6 mm in women. This distance decreases with age. Generally to evaluate complex cases both shoulders are imaged. The measurement between the coracoid and clavicle is normally 11 to 13 mm and is obviously abnormal when a difference of 50% exists between the two sides. Because of anatomical variations occur in upwards to 20% of the population for alignment of the clavicle and coracoid is considered unreliable even with weight bearing radiographs.

AC joint separations are graded I through III. Grade I separations are sprains that do not involve widening or displacement of the joint. Grade II separations are more severe in that they involve acromioclavicular ligament separation and joint dislocation or subluxation. This can be a subtle finding on x-ray because the coracoclavicular distance is within normal limits. Grade III dislocations are the only type of AC separation that may require surgery. It is characterized by dislocation and a coracoclavicular distance of at least 50% greater on the affected side compared to the normal side. The coracoid process may be avulsed or fractured. The epiphysis of the coracoid process does not fuse until about age 21 to 25 years making it difficult to diagnose AC joint fractures. Good positioning to demonstrate the AC joint and coracoid is required. The best views to demonstrate the AC joint relationships are the Axillary view, scapular Y view, or the AP view with 30-35 degree cephalic angulation.

The glenohumeral joint is the most unstable joint in the body and is therefore frequently radiographed. It is formed by the glenoid cavity of the scapula and the head of the humerus. Most traumatic dislocations are caused by indirect force. Anterior dislocations are the most common occurring about 95% of the time. They are generally caused by abduction of the arm with forced external rotation. Posterior dislocations occur only 2-4% of the time and are due to adduction and internal rotation of the arm in a flexed position. An important relationship in the shoulder is that the acromion process is posterior to the glenoid fossa, and the coracoid process is anterior to the glenoid process. As the humerus dislocates its posterolateral surface suffers compression when it is pressed against the anterior inferior rim of the glenoid. This type of fracture is called a Hill-Sachs lesion. This occurs because the posterolateral aspect of the proximal humerus is softer than the glenoid rim. Fracture of the glenoid rim also occurs in about 7% of anterior dislocations. Hill-Sachs lesions can occur in nearly 50% of anterior dislocations. Glenoid rim fractures can cause chronic reoccurring shoulder joint dislocations. Open reduction with internal fixation is required to stabilize glenoid rim fractures.

imageShoulder-02a imageShoulder-02b
These two radiographs AP on the left and scapular “Y” view on the right demonstrate an anterior dislocation of the glenohumeral joint. These dislocations are named according to where the head of the humerus comes to rest. In this case we see an anterior subcoracoid dislocation. This is the most common type followed by the subglenoid dislocation in which the humeral head comes to rest below the glenoid rim.

Unfortunately standard AP shoulder views do not demonstrate glenoid rim or Hill-Sachs lesions. These are best demonstrated with the Axillary view, Grashey view, or CT scan. The AP projection with internal rotation can rarely demonstrate the Hill-Sachs lesion. The most common complication of anterior dislocation is its reoccurrence. Other complications are related to rotator cuff tear and transient nerve injury. This occurs because the neurovascular bundle is stretched during anterior dislocation and the axillary artery or its branches are injured.

imageShoulder-02c imageShoulder-02d
The highly schematic drawing on the left demonstrates the tightly woven neurovascular bundle in the region of the axilla and proximal arm. The radiograph on the right is an arteriogram of the right axilla demonstrating the subclavian and its continuation as the axillary artery in the shoulder. Surgical neck and proximal humerus fractures must be handled carefully to avoid putting these vessels at risk to injury.
imageShoulder-03
This 3D volume rendered CT image demonstrates the anatomy of the scapula seen from the anterior surface. The scapula has three angles: the superior angle (A1), lateral angle a.k.a. glenoid process (A2), and inferior angle (A3). It also is described as having three borders: the axillary border, which is towards the axilla (B1), vertebral border (B3), and the superior border (B2). The superior border contains the scapular notch and coracoid process. Its large shadow fossa called the subscapular fossa (D) and the coracoid process (C) are seen.
imageShoulder-04
This posterior view of the scapula shows the scapular spine (B), supraspinatus fossa (A) and infraspinatus fossa (C); these two fossa house large muscles that participate in rotating the humerus.
imageShoulder-05
The scapular spine (A) separates the infraspinatus and supraspinatus fossa on the posterior surface of the scapula. It ends laterally as the acromion process (B). The acromion process is a radiologic landmark.

There are six muscles of the shoulder worth mentioning here. These are the relatively short muscles that connect the scapula to the humerus and act on the glenohumeral joint. These are the supraspinatus, infraspinatus, subscapularis, teres major, teres minor, and deltoid. Four of these join the scapula to the humerus at the shoulder joint. These are the subscapularis, supraspinatus, infraspinatus, and teres minor. They are called the rotator cuff muscles because they form a musculotendinous cuff that covers the shoulder joint. This tendinous cuff does not completely envelop the joint. The inferior axilla region is poorly secured making it the weakest joint in the body. This makes the shoulder joint vulnerable to inferior dislocation by impact when the arm is abducted. The rotator cuff muscles provide good stability to the shoulder joint by holding the head of the humerus to the glenoid cavity. The cuff muscles protect the shoulder joint, and all but the supraspinatus muscle helps to rotate the humerus thus the name rotator cuff. Their insertions on the humerus are radiographically significant, for example, the subscapularis muscle inserts on the lesser tubercle of the humerus. Teres minor, supraspinatus and the infraspinatus muscles insert on the greater tubercle. It is important that the greater and lesser tubercles are properly profiled with internal and external rotation views of the shoulder.

As we have stated, the coracoid process is on the anterior portion of the scapula within the superior border, and the acromion process is on the posterior aspect of the scapula being the lateral extension of the scapular spine. Between these two structures is the glenoid cavity or fossa. The glenoid cavity is the site for articulation of the head of the humerus that attaches the upper appendage to the shoulder girdle. There is a three-part relationship here that is radiographically significant. Radiologist and orthopedic physicians often describe relationship as the scapular “Y.” Three structures form the scapula “Y.” The arms of the "Y" are formed by the coracoid and acromion processes, the leg is formed by the body of the scapula. Being able to demonstrate the scapular “Y” and glenoid process is very important. Other ways to demonstrate this relationship include the WestPoint view, and craniocaudal shoulder view.

imageShoulder-06
This 3D CT volume rendered images demonstrates the relationship of the scapular “Y.” The CT image on the left views the scapula from the vertebral border. Notice the medial angle (B), which is anterior, and the acromion process (D), which is posterior (P). The image on the left shows the relationship of the scapula “Y” from the view of the axillary border. Notice the glenoid cavity (G) on the glenoid process. The coracoid process (C) is on the anterior surface (A), and the acromion (D) is on the posterior surface (P). The scapula “Y” is best viewed from the axillary border.

The proximal humerus is part of the radiographic anatomy of the shoulder. The humerus is the largest bone of the upper extremity. Its superior end possesses a smooth ball-like head that articulates with the glenoid fossa of the scapula. Several muscles hold the humerus in the glenoid cavity and move it. The greater and lesser tubercles are separated by an intertubercular groove that is a gutter for the tendon of the long head of the biceps muscle. An ill-defined anatomical neck separates the head from the tubercles. A tapered region just below the anatomical neck where the shaft begins is called the surgical neck because it is the site where fractures of the proximal humerus most often occur.

imageShoulder-07
These 3D volumes rendered series of CT images demonstrate parts of the proximal humerus. The humeral head (A), lesser tubercle (B), greater tubercle (C), surgical neck (D), anatomical neck dotted line (E), and the groove for the long head of the biceps muscle (F).

It is important to our study of shoulder radiography that you have reviewed your anatomy and can identify these parts on a shoulder radiograph: head of the humerus, greater and lesser tubercles, anatomical neck, surgical neck, and the body of the humerus. The clavicle, acromioclavicular joint, coracoid process, acromion process, glenohumeral joint, glenoid cavity, and all three borders and angles of the scapula should also be identified. These parts will be further discussed when we focus on the radiography and film critique of the shoulder later in this module. Consider the radiograph below that identifies some of these structures:

imageShoulder-08
Some important anatomy to be familiar with is shown on this radiograph: (A) greater tubercle, (B) acromion, (C) clavicle, (D) humeral head, (E) glenoid process, (F) medial or vertebral border of scapula, (G) coricoid process, (H) inferior angle of scapula, (I) 5th rib, (J) axillary border of scapula.

Now that we have discussed some basic anatomy of the shoulder we are ready to look specifically at ways in which we image it. Some of the radiographic views commonly performed include: AP views (internal and external rotation), scapular “Y” view, axillary view, and Grashey view. Keep in mind that each of these views is designed to demonstrate specific anatomy and have specific diagnostic criteria. While there are common criteria for imaging the entire shoulder there are specific criteria for each view taken in a series such as a trauma series or a routine survey that does not involve trauma. Often orthopedic surgeons will request special views that are not commonly done and are not included in this film critique. So let’s begin by looking at the specific diagnostic criteria for imaging the shoulder.




Upper Extremity Film Critique- Part I
The purpose of this critique is to raise the technologist’s awareness of what radiologists and orthopedic physicians require when diagnosing and treating injury and disease involving the upper extremity. It is hoped that your examination of this radiograph treatise will result in your production of better radiographs.

The routine views of the shoulder are:

  1. The standard three AP shoulder views are taken with the humerus in neutral, internal, and external rotations;
  2. Axillary lateral;
  3. Scapular "Y";
  4. Transthoracic lateral;
  5. Grashey projection;

This lesson is organized so that images are presented so that you can apply the diagnostic criteria to each view. You should write down your comments concerning the anatomy demonstrated, correct positioning of the anatomy, radiographic exposure technique, and presentation (properly marked, no artifacts, centered, and the like).

Diagnostic Criteria for Imaging the AP Views of the Shoulder

Radiography is both an art and a science. We have all heard this since our first day in x-ray technology school. When we look a radiograph that we create it is our signature to the way in which our individualism is practiced within the guidelines of our professional responsibilities. Our duty is to produce quality radiographs that are optimal for interpretation. Each radiograph that we take should be accurately positioned, have adequate penetration of the part, have the proper density and contrast, be free of unwanted motion, and be free of artifacts caused by dirty equipment or removable items on the patient. Other issues like putting the position marker on the outer lateral edge of each film and proper patient identification on each image are hallmarks of a good radiographer. For example, in shoulder imaging the positioning marker is placed on the upper lateral edge of the shoulder. A position marker should be used to identify each view, for instance, turning a direction arrow towards the torso for internal rotation of the humerus, and away from the torso for the external rotation of the humerus view. While these tips are not an absolute part of what we will discuss for every view’s diagnostic criteria they do speak loudly to the professionalism and style of each radiographer.

  • Accurate positioning for the shoulder involves putting both shoulders at equal distances from the tabletop. This will place the midcoronal plane parallel with the tabletop. A well-positioned, well-collimated AP radiograph in the absence of trauma should demonstrate the lateral two-thirds of the clavicle, glenohumeral joint and upper scapula and proximal humerus. Trauma shoulder views should include the entire clavicle, entire scapula, and proximal humerus.
  • The internal rotation film is taken with the epicondyles of the humerus perpendicular to the tabletop. Internal rotation of the humerus profiles the lesser tubercle medially. The external rotation film is taken with the epicondyles parallel to the tabletop. External rotation of the humerus projects the greater tubercle laterally. These two films also provide some incite into the articulation of the acromioclavicular joint.
  • Proper density and contrast involves a well-chosen kVp for the shoulder and controlling scatter radiation. The recommended kVp range for imaging adolescent and adults is between 70-80 kVp for screen film, and for digital imaging between 75 and 85 kVp. This range of exposure technique will result in a well-penetrated shoulder radiograph with good bone detail. Soft tissues around the shoulder and acromioclavicular joint should be optimally visualized. As a general rule, the cortical outline of bone will be visible on an underexposed film but will not be seen on an underpenetrated film. Also the background density will be light if the film is underexposed, and a dark background density and a light radiograph generally means the part is underpenetrated. You should use these rule to correct images that are underpenetrated or under exposed. Scatter reaching the image receptor must be controlled in order to bring out the maximum detail in the shoulder. Some basic things that should be done are to use a grid for parts over 10 cm, collimate appropriately to the part, and in some instances use a flat lead blocker to attenuate scatter along the edge of the collimated area. Applying these standards will help produce radiographs that have the proper density and contrast. Sometimes either a high contrast film or a low contrast film is acceptable for diagnosis. High contrast is good so long as it does not burn out the acromioclavicular joint and the spine is well penetrated. Low contrast is acceptable so long as image noise or quantum mottling does not compromise the subject detail.
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Notice the radiograph on the left is a high contrast image. Subject detail is enhanced and it is still a good exposure because the AC joint is clearly visible and the spine well penetrated. The radiograph on the right is a low contrast image with good penetration of the spine and ribs. Notice that the low contrast image technique does not overly compromise subject detail. Both of these radiographic extremes are acceptable because of the skilled exposure management by two different technologists. This degree of latitude does not exist with all patients so you should attempt to find a good exposure that demonstrates bone and soft tissues.

  • Any object that obstructs the anatomy under investigation and can be removed is an artifact. An object that may produce a film artifact should be removed prior to imaging. Sometimes with trauma imaging artifacts like ECG monitor leads, oxygen saturation monitor lead or cord, or even a necklace hidden under a cervical collar should be removed or repositioned out of the critical field of view. Some artifacts must be removed and the image repeated for obvious legal reasons. Anatomic artifact caused by superimposed structures like the hand over the shoulder must also be repeated. Equipment artifacts like processor streaks, improper grid alignment causing grid lines on the radiograph, or digital noise must all be repeated and cannot be considered acceptable radiographs.
  • All images with excessive motion or that have streak artifact that should be repeated. Good patient instructions and using high mA will alleviate most motion artifacts. Writing the number of images on the radiology request, and the technical factors used will alert the radiologist when multiple views are included as repeats.
  • Three views of the shoulder in the AP projection are commonly made. 1) AP view of the shoulder with internal rotation of the humerus. This view profiles the lesser tubercle medially. The epicondyles on the distal humerus should be perpendicular to the tabletop and superimposed anatomically for the internal rotation view. 2) The AP view of the shoulder with external rotation of the humerus is made with the arm adducted close to the body. The epicondyles of the humerus are positioned parallel to the image receptor. External rotation of the humerus will project the greater tubercle laterally. 3) For a neutral position the humerus is placed at the patient’s side. This places the epicondyles at near 45-degrees to the tabletop projecting the greater tubercle slightly lateral. Use a directional marker like an arrow to indicate which view is the internal, external, or neutral view. Turn the position marker (L or R) towards the torso for internal rotation of the humerus or use an arrow pointing towards the torso. Turn the position (L or R) marker away from the torso for external rotation of the humerus, or use an arrow pointing away from the torso.
  • A projection that can provide good information about the shoulder joint because it demonstrates the glenoid process in a true lateral is the Grashey view. The purpose of the Grashey view is to demonstrate the glenoid process in profile and the glenohumeral joint space open. The Grashey view places the patient in an oblique position in order to accomplish this. The scapula’s anatomical orientation is 35-40 degrees oblique following the curvature of the posterior ribs. On the standard AP views this causes a distortion in the presentation of the shoulder joint with overlap of the anterior and posterior margins of the glenoid process. This is why the nondisplaced shoulder joint shows some superimposition of the humeral head and glenoid fossa. A good Grashey view will profile the glenoid process a.k.a. lateral angle of the scapula, coracoid process, and the joint space of the glenohumeral joint.
  • When appropriate collimate to reduce patient radiation exposure when the clavicle or acromioclavicular joint is the subject. This will reduce patient dose and promote the principle of ALARA (As Low As is Reasonably Achievable).
  • Radiographic technique must show good bone detail and outline the contour of bone and joint articulations. To penetrate the shoulder of an infant approximately 60 kVp is recommended. For children and adults a range of 70-80 kVp is recommended. A grid should be used of adult imaging but not for infants. As a general rule anytime the part is greater than 10 cm a grid should be used. If screen-film is used, it is recommended that you not use detail screens for imaging the adult shoulder. This will increase patient dose as more mAs is needed to compensate for detail screens. Soft tissue detail should provide low contrast detail visualizing muscles, fat, and air densities.
  • In acute trauma imaging these AP views may be modified to accommodate the patient’s presentation. Trauma and post surgical changes most commonly represent reasons to modify how a projection is taken, but not the anatomy and the way it is demonstrated.
Radiograph #1

image001 Using the diagnostic criteria as your basis for critique of this AP shoulder in neutral position; state what should be included in this view and tell whether or not the patient is properly positioned? Is this an acceptable radiograph for trauma imaging, tell why or why not?

Critique of Radiograph #1

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    This radiograph includes the required anatomy stated in the diagnostic criteria. The entire clavicle, scapula, and proximal humerus are demonstrated. The humerus is in a neutral position, which places the epicondyles at 45-degrees to the coronal plane. The hand is placed with the palm touching the side of the thigh. We can see the anatomical relationship of the shoulder and acromioclavicular (AC) joints on this radiograph. Good radiographic exposure has been accomplished. Contrast balance between bone and soft tissue detail is well appreciated on this radiograph. The soft tissue around the AC joint is important to see, which is nicely demonstrated by the chosen radiographic exposure technique. A good well-penetrated thoracic spine silhouette is demonstrated along with good rib detail. What makes this exposure nice is the penetration of the ribs and scapula while the lung is not overexposed. This is an excellent radiograph of the shoulder for trauma imaging.

Radiograph #2

image002 This patient’s chief complaint is intense shoulder pain following a fall on an abducted arm. Tell how this radiograph should have been taken along with your critique of it considering the patient’s history.

Critique of Radiograph #2

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    Our critique should always be based on the diagnostic criteria. The anatomy for a trauma survey states that the entire clavicle and scapula, and proximal humerus must be demonstrated. This should be seen on at least one of the AP views in a two or three view series. Additionally, when imaging we should always attempt to remove all metal objects such as necklaces, bra straps, ECG leads, wires and so forth from the field of view. Metal being more radiopaque than bone will obstruct visualization of the anatomy.

    As for the radiographic exposure technique seen on this film, the subject contrast is too high. The failure to penetrate the thick latissamus dorsi muscle group is quite evident by the underpenetrated lateral rib margins. Did you notice that the soft tissue around the AC joint on this radiograph is not well demonstrated as in radiograph #1? Marked swelling around the AC joint is an important indicator of injury. Here we cannot see the AC joint without the aid of a “hot light.” The extent of the clavicle fracture is difficult to see because of the high contrast exposure technique. Using a fixed kVp and varying mAs exposure chart will standardize contrast for extremity imaging. To optimize this radiograph use the 50/15 rule to decrease the mAs and maintain overall radiographic density.

Radiograph #3

image003 Can you state the name of this view and identify the structure at the pointer? Critique this radiograph paying attention to the positioning and radiographic exposure technique.

Critique of Radiograph #3

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    This AP view demonstrates external rotation of the humeral head profiling the greater tubercle laterally (yellow arrow). This is a growing adolescent patient evidenced by the epiphyseal plate (white arrow). The required anatomy is properly displayed and this radiograph is properly collimated. Demonstrating the proper anatomy and correct positioning alone does not complete the diagnostic standard. The main reason this radiograph does not meet the diagnostic criteria is that the subject contrast is too high. The scapula is not well penetrated nor is the soft tissue around the acromioclavicular joint adequately seen. Penetration of the sternoclavicular joint, glenoid process, and visualized thoracic spine is unsatisfactory. This radiograph must be repeated because these structures are not adequately penetrated. Adjust the exposure technique using at least a 15% increase in kVp and a 50% reduction in the mAs.

Radiograph #4

image004 Using the diagnostic criteria for the trauma AP shoulder view what are your observations about this radiograph.

Critique of Radiograph #4

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    We see the shoulder is raised as in guarding to reduce pain. Patients who sustain acute trauma are in pain and tend to guard their injury. When a patient presents like this you should take time to relax your patient by coaching them to lower their shoulder. Gently assure the patient that you will not intentionally add to their pain and explaining to them the need to relax the shoulder to improve image quality. Most patients will cooperate if it is possible with good explanation and patient coaching to lower the shoulder. The other problem with this radiograph is that portions of the proximal humerus, scapula and clavicle are clipped. This is not acceptable and requires that the radiograph be repeated. As for the radiographic contrast there is good subject contrast and balance between bone and soft tissues around the visualized parts of the shoulder.

Radiograph #5

image005 Using the diagnostic criteria as a guide, discuss why this exposure is unacceptable, and discuss any positioning error you may see.

Critique of Radiograph #5

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    This patient’s body presentation is to some extent kyphotic. The radiograph shows an apical lordotic view of the chest and shoulder. To represent this patient’s anatomy in anatomical position the CR should be appropriately angled caudal. Unfortunately the patient’s large size has contributed to under penetration of the glenoid process and scapula. This image should be repeated using exposure factors that penetrate the axillary border of the scapula and provide uniform densities throughout the shoulder. This is a common problem with using too low kVp for the shoulder region. It is especially noticeable with obese and muscular patients. Sharp bone detail is desirable for bone imaging may not be a good imaging strategy for imaging the shoulder. Our goal is to demonstrate the soft tissues around the AC joint and well penetrate the scapula. For this reason a slightly long scale or low contrast image is preferred. When the axillary rib margins, soft tissues around the acromioclavicular joints, and the body of the scapula are demonstrated the subject contrast is optimal.

Radiograph #6

image006 This patient presented to the emergency room with a sports injury in which he was slammed onto a mat during a wrestling match. Critique this radiograph using the trauma AP shoulder criteria as your guide.

Critique of Radiograph #6

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    It’s a wise practice in some situations to take trauma images in the “as is” position. This is the case with this radiograph. The technologist opted not to manipulate the patient’s arm. Of course you may have to repeat the radiograph later when anatomical positioning is possible and safe to pursue. There are several reasons this radiograph should be repeated. First, the entire clavicle should be well-penetrated both extremities and their respective joint articulations must be well delineated. Notice how underpenetrated the sternoclavicular joint and thoracic spine is. A correct penetration of the thoracic spine without overexposing the soft tissue around the AC joint is an optimal exposure. This is a high contrast exposure that has diminished the diagnostic quality of the radiograph. The kVp is insufficient and the radiograph is overexposed. An x-ray beam in the range of 70-80 kVp is recommended. This will appropriately penetrate the shoulder to provide the proper subject contrast. An optimal kVp in the stated range will not only produce suitable subject contrast and bone detail, as well; superior soft tissue detail will be depicted.

Radiograph #7

image007 What is your critique of this trauma radiograph, be sure to comment on the technical factors used to make this radiograph?
Critique of Radiograph #7

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    What stands out most about this radiograph is the graininess of the image and lack of subject contrast. Several factors have contributed to this poor image quality: 1) quantum mottle, 2) fog due to scatter, and 3) fog to light or heat. Probably the most significant cause of this poor radiograph is that it is underpenetrated and lacks sufficient mAs to bring out subject detail. Increasing the kVp will result in a better radiograph because it will increase the quantity of photons reaching the film. This will significantly improve the overall subject detail. Too reduce the scatter reaching the film a grid should be used, but this will also require an increase in the mAs. The amount of mAs increase will depend on the type of grid used, a 12:1 grid or higher is recommended. It is not always necessary to use a grid, for example, when imaging small children or when the part is less than 10 cm. A regular high-speed screen-film combination will yield good results without using a grid. Special detail film and cassettes will require significant exposure similar to using a grid and the result is not always better than using a bucky. Digital detail cassettes will result in a better radiograph than using film-screen cassettes when processed with a bone algorithm. Notice the upper and lower edges of this radiograph outside the collimated area show fogging either due to scatter, high temperature, or chemical causes.

Radiograph #8

image008 This seems like a good radiograph of the shoulder, how would you critique it if this represents a routine shoulder view, and if it represents a trauma view; what is the position of the humerus?

Critique of Radiograph #8

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    This radiograph demonstrates the humerus in external rotation. Notice that the greater tubercle is profiled laterally. Had the entire clavicle and been included on this film it would have been a radiograph that meets the diagnostic criteria for trauma imaging. As is stands, this radiograph would meet the diagnostic criteria for a routine shoulder view with external rotation of the humerus. This image need not be repeated if the entire clavicle is included on the internal rotation view of the shoulder. Good exposure factors have been selected: there is good bone penetration, excellent subject detail in the shoulder joint, and the ribs along the axillary border are easy to evaluate. Especially noteworthy is the quality of the soft tissue detail around the AC joint and clear differentiation of the superior, vertebral, and axillary borders of the scapula. This is a good radiograph!

Radiograph #9

image009 Did the technologist meet the diagnostic criteria for this radiograph taken for trauma; state your reasons for your answer?

Critique of Radiograph #9

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    Whenever there is trauma involving the shoulder with obvious deformity the technologist should include the entire clavicle, scapula, proximal humerus, and soft tissues surrounding these structures. The medial clavicle is not entirely included, and the inferior angle of the scapula may be clipped as well. The problem with not including the entire clavicle is that the orthopedic physician will want to see the entire clavicle before reducing the dislocated shoulder joint. An impact sufficient enough to dislocate the shoulder could have caused injury to the sternoclavicular joint. To avoid taking unnecessary repeat views it is recommended that the entire clavicle be included with trauma is given in the patient history for the study. The metallic electrocardiogram (ECG) leads should be moved prior to repeating this radiograph of the shoulder. A pair of ECG leads is seen obstructing the anatomy in this radiograph.

Radiograph #10

image010 What is your critique of this radiograph taken for traumatic injury to the shoulder; tell what should be done to complete the diagnostic criteria?

Critique of Radiograph #10

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    It is easy to think that because this radiograph shows an avulsion of the greater tubercle that the complete diagnosis has been made. We still have to apply the diagnostic criteria for the trauma AP shoulder to this projection. Since radiographers do not interpret radiographs it is important that the criteria are met for each view. When we look at this radiograph and compare it to the diagnostic criteria we see that the entire clavicle should have been included. It is also important that we see the soft tissues of the shoulder and around the AC joint. Optimum radiographic exposure is needed to penetrate of the shoulder and provide good soft tissue visualization. Basically, the high contrast seen here should be adjusted to a much lower scale to bring out more gray tones. A higher kVp selection would better penetrate the scapula and axillary ribs to add to the diagnostic quality of this radiograph.

Radiograph #11

image011 What is your assessment of this trauma shoulder radiograph; tell whether the humerus is internally or externally rotated?

Critique of Radiograph #11

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    The greater tubercle is profiled laterally so the humerus is externally rotated. This is a trauma projection so the technologist appropriately included the entire scapula, clavicle, and upper humerus. Whenever I see a good radiograph like this one it amazes me that a technologist would cast a blemish on their fine work by not removing a necklace or snaps on a gown. Use good judgment and remove necklaces and other metal that may obstruct the view before making an exposure. Most of the public knows that they will have to remove metallic objects for x-ray imaging. Don’t try to get away with leaving metal in the area of interest. These types of exposures are almost always repeated. As for the radiographic technique, this radiograph demonstrates good bone detail without burnout of the AC joints and soft tissues. The exposure technique is at the upper limits of what is an acceptable high contrast image. The thoracic spine is under penetrated, which indicates the contrast is marginally high. Try to demonstrate the vertebral bodies of the thoracic spine and soft tissue detail of the AC joint, which are indicators of optimal radiographic exposure technique.

Radiograph #12

image012 What is your assessment of this shoulder radiograph taken for trauma, and tell what improvement(s) can be made to express adherence to the principle of ALARA?

Critique of Radiograph #12

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    This appears to be a very good radiograph of the shoulder with the humerus in external rotation. The main reason this radiograph should be repeated is that it is inappropriate collimated. The entire clavicle is not included in this trauma survey, and an excessive amount of the humerus and chest is included in the collimated field. In keeping with ALARA better lengthwise collimation should have been applied, while less collimation along the width to include the entire clavicle is recommended. This radiograph may not need to be repeated if the entire clavicle is seen on another AP view. The exposure technique is adequate for the shoulder.

Radiograph #13

image013 What is your critique of this radiograph considering the history given is “postoperative evaluation of prosthesis;” state reasons for why this is or is not a good radiograph?

Critique of Radiograph #13

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    This is a close call on the inclusion of the entire prosthesis. We can say this is a good radiograph for several reasons. The entire clavicle, scapula, and prosthesis are demonstrated. The radiographic technique is correct for what this image is demonstrating. This is a postoperative radiograph so rotating the humerus as in internal or external rotation views is contraindicated. The humerus remains in its immobilized position during imaging unless instructions are received from the orthopedic surgeon. If a lateral view of the prosthesis is requested a scapular “Y” view should be made. This radiograph is acceptable based on modification to compensate for the patient’s clinical history.

Radiograph #14

image014 Is this a radiograph that meets the diagnostic criteria for the AP shoulder view, assume trauma for a history; state reasons for your answer and discuss the exposure technique chosen?

Critique of Radiograph #14

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    This radiograph presents several interesting issues for critique. There are obvious fractures involving the glenoid process, clavicle, and the proximal humerus. These injuries are difficult to see because the contrast is too high. Notice that the scapula’s lateral border is under penetrated and the ribs along this margin are not well seen. The visualized thoracic spine is poorly penetrated. The overall presentation of the radiograph shows sufficient density because it is overexposed. The net result is a high contrast image, which is the main reason this radiograph must be repeated. High contrast has diminished visualization of soft tissues. Soft tissues provide important diagnostic information about an injury, such as ligament damage, bacterial seeding into an open wound, a localized hematoma and other injuries commonly seen with trauma. High contrast exposures can make it difficult to see soft tissue signs of injury. Decreasing the mAs and increasing the kVp can bring out a good balance between bone and soft tissue detail. There is over collimation of the lateral soft tissues of the shoulder, this too should be corrected.

Radiograph #15

image015 Does this radiograph meet the diagnostic criteria for a non-traumatic routine AP view of the shoulder?

Critique of Radiograph #15

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    This is a very nice radiograph because it demonstrates the anatomy discussed in the diagnostic criteria for the AP shoulder view. The technologist failed to have the patient remove their bra (arrows), which is a common oversight. You should consider removing it or pulling it down below the surgical neck of the humerus. The exposure technique is acceptable because the glenoid fossa and humeral head is well penetrated. The lateral border of the scapula is poorly penetrated so I would consider using the 50/15 rule to increase the kVp and lower the mAs. This adjustment will lower the contrast but maintain the same density across the film.

Radiograph #16

image016 What is your critique of this coned internal rotation view of the shoulder?

Critique of Radiograph #16

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    This radiograph has all of the reasons not to use a cone for shoulder radiography. We have to assume that no trauma is involved because the entire scapula and clavicle cannot be included using a cone. Using a cone increases subject contrast so does using a high grid ratio grid like an 8:1 or greater. So what has happened is that too many factors that contributed to high contrast are combined. The result is poor demonstration of soft tissues throughout the shoulder, especially around the AC joint and lateral border of the scapula. There appears to be an AC joint separation (double arrowhead). Therefore, it is important that the radiologist can see the soft tissue around the AC joint. See how high contrast imaging causes “burn out” of the soft tissues? Repeat this projection without the cone so the entire clavicle and scapula is demonstrated. Adjust the exposure technique so that soft tissue detail is recognizable.

Radiograph #17

image017 Obviously this radiograph is not diagnostic, state reasons why you may or may not agree; tell what projection of the shoulder is being demonstrated?

Critique of Radiograph #17

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    This is a coned Grashey projection (a.k.a. posterior oblique projection). It is difficult to see the greater and lesser tubercles and other soft tissues because the contrast is too high.. Beware of factors that cause high contrast like high mAs low kVp, a high grid ratio and use of a reciprocating bucky, and using a cone or extension cylinder. Use of a grid is necessary when the part is greater than 10 cm, but don’t combine factors that affect contrast adversely. Clearly the soft tissues are obliterated and bone detail is lacking. Soft tissue is better seen with low contrast than with high contrast. Remember soft tissues like fat and air decrease photon absorption so high mAs will be represented as overexposure. These additional photons when they reach the image increase radiographic density and diminish visualization of soft tissues. This radiograph should be repeated because of the opaqueness through the shoulder that obstructs most of the anatomy.

Radiograph #18

image018 What is your critique of this shoulder radiograph taken for acute traumatic injury?

Critique of Radiograph #18

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    This radiograph provides good imaging to evaluate the shoulder. It meets the diagnostic criteria for demonstrating the entire scapula and clavicle, and the proximal humerus. As with all suspected fracture or dislocations, radiographs are made with the arm as is. There is good penetration of the humeral head and glenoid process. With the type of injury seen here, the lateral margins of the ribs should be better penetrated to evaluate them for possible fracture. This radiograph narrowly meets the requirements for diagnosis. Be aware that it is at the upper limits of having too high contrast. The soft tissues around the shoulder are nearly obliterated. Correct the exposure on follow up post reduction films when this is the case.

Radiograph #19

image019 What is your critique of this radiograph of the clavicle taken for a follow up chronic nonunion fracture?

Critique of Radiograph #19

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    Our radiology exam request specifies the clavicle so this radiograph is a correct interpretation of those orders. However it is recommended that the entire glenohumeral joint be included so the shoulder relationship to the clavicle can be appreciated. Collimating to the area of interest is acceptable for follow-up imaging. As for the exposure technique, high contrast is demonstrated here; however, a lower contrast with better penetration of the medial extremity of the clavicle would be optimal. This radiograph does not need to be repeated.

Radiograph #20

image020 This radiograph has lots of reasons to be repeated, give your critique it and suggestions to make any repeated radiograph diagnostic?

Critique of Radiograph #20

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    This radiograph is a combination of unsatisfactory technique selection and substandard positioning. It is not uncommon for an injured patient to guard an injury as this patient is doing. The shoulder should be relaxed and lowered so that the anatomy is not distorted. A better set of radiographic exposure factors must be selected to improve this radiograph. The background density is sufficient; however, the subject contrast is extremely poor because the shoulder is not adequately penetrated. To correct these findings increase the kVp and use a grid to improve subject detail. A compensatory increase in the mAs when using a grid is required.

Radiograph #21

image021 What is your critique of this trauma shoulder radiograph; tell whether or not it meets the diagnostic criteria and what should be done if it does not?

Critique of Radiograph #21

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    This radiograph is another example of why some trauma imaging scenarios require the patient’s humerus be left in a neutral or "as is" position. The axillary blood vessels and brachial nerve plexus are of great concern when the shoulder is injured in this manner. This appears to be an obese patient and an increase in kVp is required. The use of a grid is also required because the part is greater than 10 cm. The shoulder joint is dislocated and there is an avulsion fracture of the greater tubercle as well as other findings. The radiographic exposure shows high contrast, which is not recommended for good soft tissue detail. With this magnitude of trauma the technologist should have included the entire clavicle and scapula. Soft tissue detail around the acromioclavicular and glenohumeral joints is grossly overexposed. When the follow-up radiograph is taken adjust the kVp and mAs to show good bone penetration and balanced display of the soft tissues around the AC joint.

Radiograph #22

image022 What projection of the shoulder is this; discuss whether or not it meets the diagnostic criteria?

Critique of Radiograph #22

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    This is an AP scapula projection. Notice that the entire clavicle and scapula are included (arrows). The arm is appropriately abducted to bring the scapula away from the rib cage. Considering the extent of this patient’s injuries the arm could not be further abducted to bring the scapula away from the lateral rib margins. Scapular fractures usually result from violent direct trauma. Evaluation of several structures is warranted because of the extent of injuries seen here. Radiographic evaluation must include the ribs for fractures, the lung for pneumothorax or hemothorax, soft tissues for subcutaneous air, and the scapula. The scapula rests against the posterior ribs and is well protected by muscles. So these surrounding tissues and ribs can be injured when the scapula is fractured. An insightful radiographer will always choose an exposure technique that allows for evaluation of all bony and soft tissue structures when imaging the shoulder for trauma.

Radiograph #23

image023 Name this view and tell how the patient is positioned for it, be sure you critique it using the diagnostic criteria.

Critique of Radiograph #23

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    If you recognized this as the Grashey view (a.k.a. posterior oblique view) you are right. An accurately positioned Grashey view will demonstrate an opened glenohumeral joint space, profiled glenoid process and humerus articulation with the glenoid fossa. The humerus is properly positioned in external rotation. This would be a much better radiograph if the shoulder were more penetrated. The subject contrast is definitely too high. While good bone detail is desired, it cannot be achieved with high mAs alone there must be a balance between bone detail and soft tissues. Good positioning, adequate bone penetration, grid selection, proper kVp and mAs all play a role in overall quality of the image. Remember, there is a lot of thick muscle in the shoulder and proximal humerus. Abducting the arm just slightly so the biceps do not cast a shadow over the ribs as it does in this radiograph will also help improve subject contrast. The main reason this radiograph should be repeated is that the shoulder is underpenetrated and lacks subject detail.

Radiograph #24

image024 What is your critique of this postoperative scapula radiograph?

Critique of Radiograph #24

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    This is a post operative radiograph that requires the entire scapula be demonstrated. An obvious observation is that the inferior border of the scapula has been clipped. You can palpate the inferior scapula border prior to placing the patient against the image receptor. The length of the scapula will vary with body habitus; it usually extends down to the seventh rib. Because this is a post-op film you cannot be negligent in presenting the requested anatomy. It may be necessary to turn a 10 X 12 cassette lengthwise to include the entire shoulder and scapula. Otherwise this radiograph has appropriate diagnostic density and contrast.

Radiograph #25

image025 Critique this radiograph taken for “f/u ORIF left scapula” and tell how it compares to the one above (#24).

Critique of Radiograph #25

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    You may have noticed that this radiograph is the repeat of radiograph #24. This time the technologist included the entire scapula. Notice that the entire internal fixation devices are visible. The surgeon can get a better evaluation of the scapula from this radiograph. It is good that the technologist repeated this radiograph. Remember, whenever the physician’s order specifies a part like the scapula, you are required to entirely include it to avoid malfeasance. This is an excellent radiograph!

Radiograph #26

image026 Given a history of possible clavicle fracture due to trauma, what is your critique of this radiograph?

Critique of Radiograph #26

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    This radiograph was taken with the patient's humerus in the AP neutral position. The entire clavicle, scapula, and proximal humerus are included. This appears to be a good radiograph that demonstrates the clavicle, shoulder joint and scapula very well. However, this is also a high contrast radiograph. This is a bit confusing to determine because the lateral rib margins have good subject contrast. But the give away is the lack of penetration of the visualized thoracic vertebrae and overexposure of the AC joint and its surrounding soft tissues. The radiographic density on this film is owed to high mAs. As a result the lateral end of the clavicle and AC joint is poorly seen. A lower contrast radiograph with a more penetrating beam will resolve these concerns. Optimal kVp range for shoulder radiography is between 70 to 80 kVp for most persons of average size.

Radiograph #27

image027 What is your critique of this bilateral clavicle view taken for trauma? Tell why the physician requested both shoulders on this view.

Critique of Radiograph #27

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    Both right and left sides are sometimes requested on children who are still growing, especially if the AC joints are suspected to be involved. Sometimes a discrepancy between the two sides is the only indicator of an AC joint separation. Children and adolescents still have epiphyseal plates and metaphysis bone formation. Usually one side provides a comparison for the other so that an epiphyseal plate is not mistaken for a fracture, or a fracture is missed because it mimics a growth plate. Like any shoulder radiograph we must demonstrate the soft tissues of around the AC joints and have good penetration of the upper thoracic. This subject contrast is too high and the soft tissues are obliterated. Notice the fracture of the left clavicle. The lateral extremity of the clavicle is overexposed. I would recommend greater penetration of the shoulder, scapula, and ribs. Use the 50/15 rule to maintain overall radiographic density, but lower the contrast by increasing the kVp.

Summary of the Critique of the AP Views

  • The AP view must demonstrate the entire scapula, clavicle, and proximal humerus for the trauma series. In the absence of trauma the anatomy to be demonstrated is the lateral two-thirds of the clavicle, entire glenoid fossa, coracoid, acromion and the lesser and greater tubercles of the humerus.
  • The AP view of the shoulder with internal rotation of the humerus must profile the lesser tubercle medially. Position the patient so that the epicondyles are superimposed in a position that is perpendicular to the image receptor.
  • The AP view of the shoulder with external rotation of the humerus must profile the greater tubercle laterally. The arm should be close to the body (adducted) and the epicondyles parallel to the tabletop.
  • The Grashey view must profile the glenoid process, open space of the glenohumeral joint and coracoid process.
  • When appropriate collimate to a specifically named part, such as: the clavicle, acromioclavicular joints, or scapula. This will reduce patient dose and promote the principle of ALARA.
  • These AP views may need to be modified according to the patient’s presentation. Trauma and post surgical changes most commonly present reasons to modify a projection, but not the anatomy demonstrated. The humerus remains in the “as is” position unless the ordering physician specifies it can be moved.
  • Radiographic technique must show good bone detail. Bone contour including the cortical margins, spacing of all joint articulations, and soft tissues must be demonstrated. High quality soft tissue detail to visualize muscle, fat, and air densities should be achieved. Those soft tissues surrounding the shoulder and AC joint must be easily seen. A harmonized technique that demonstrates the inferior and lateral angles of the scapula should be achieved. The thoracic spine and lateral margin of the ribs should show good contrast and fine bone detail.
You should always ask yourself with each image taken, "Did I achieve the diagnostic criteria for this view?" Diagnostic Criteria for the Axillary view a.k.a. Craniocaudal Projection

The Axial Shoulder view a.k.a. Craniocaudal or Inferosuperior Projections

The purpose of this view is to identify fractures or dislocations not evident on frontal views alone. Posterior dislocations of the humeral head are particularly difficult to diagnose from the AP views. Diagnosis is based on the ability of the technologist to demonstrate the proper anatomy in the correct positioning. A properly taken axial shoulder view will have the proper density, contrast, and penetration to demonstrate the articulation of the glenohumeral joint. The entire coracoid and its base, acromion process, and lateral extremity of the clavicle, AC joint, scapular spine and posterolateral portion of the head of the humerus should be demonstrated. For maximum diagnostic quality it may be necessary to use a grid when the inferosuperior measurement exceeds 16 cm. This projection is very important because it is able to demonstrate a type of depression fracture not easily seen on other shoulder views called the Hill-Sachs defect. This projection also demonstrates anterior and posterior dislocations of the glenohumeral joint. Positioning for this projection can be tricky, so let’s review the particulars of this view in terms of anatomy demonstrated, proper positioning, and radiographic critique.

imageShoulder-11
The following are named parts on an axial radiograph: (A) coracoid process, (B) glenohumeral joint, (C) lesser tubercle; (D) posterolateral humeral head, (E) acromion, (F) spine of the scapula, (G) glenoid process, and (H) base of coracoid. This anatomy should be demonstrated on the craniocaudal radiograph of the shoulder. Notice the proper way to present this view is with the anterior side up. Notice that the superior and inferior margins of the glenoid fossa are superimposed and the lateral margin of the coricoid base is aligned with the glenoid fossa. The humerus is externally rotated to demonstrate the lesser tubercle (C) projected anteriorly.

The patient is positioned lying supine with the affected arm abducted 90 degrees to the body, which places the glenoid fossa at 30-35 degrees to the coronal plane. This requires that the horizontally directed CR enter the shoulder at the transverse level of the coracoid process making a 30-35 degree angle with the lateral body wall. When positioning the patient it is important that abduction of the arm moves the scapula and the glenohumeral joint into the proper position. The head of the humerus is centered in the radiograph, the humerus in slight external rotation. Proper positioning will demonstrate the lesser tubercle anteriorly and the posterolateral humeral head in profile. The arm should be fully extended and in slight external rotation to properly demonstrate the lesser tubercle anteriorly. Foreshortening of the humerus occurs when the arm is less than 90 degrees, and is pronounced when the arm is at 45 degrees to the axillary body surface. Some patients are only able to abduct the arm to about 45 degrees due to pain or fracture. When the ordering physician requests this view under these circumstances certain adjustments to the tube angle will be required. For example, when the arm is abducted 45 degrees to the body the CR is correspondingly angled 20 degrees towards the body. The arm will be foreshortened, but the relationship at the glenohumeral joint will be preserved. A sponge or towel can be placed under the affected arm raising it 2-3 inches above the tabletop. This will prevent clipping of the posterior aspect of the shoulder and humerus. The cassette or imaging receptor is aligned vertical and perpendicular to the x-ray beam. Support the cassette using sandbags so that the patient’s arm can be fully extended. Having the patient hold the cassette requires the arm to be improperly abducted. Flexion at the elbow causes the greater tubercle to be projected posteriorly, which is undesirable positioning.

imageShoulder-12
On this radiograph the patient is positioned correctly with the glenoid fossa aligned to the edge of the base of the coracoid process. The inferior and superior margins of the glenohumeral joint are nearly superimposed. However the patient’s arm is not fully abducted to 90 degrees. Note the amount of foreshortening of the humerus (white arrow points to the elbow). The CR was properly aligned less than 30 degrees to the lateral body surface to enter at the glenoid process to compensate for the poor adduction of the arm. Because of these compensations the relationship of the glenohumeral joint is preserved.

If the patient is allowed to remain upright the arm is stretched over the cassette, a flat or curved cassette can be used. When the patient is unable to abduct the arm to 90 degrees a modified axillary view may be used. Because the classical described axillary view of the shoulder is not always possible when trauma results in pain or fracture, a less painful modified axillary view can be performed. It is described here as if the patient is upright; however it can be performed with the patient lying supine. Bend the patient from the standing or sitting position forward over the cassette. The CR is given a craniocaudal inclination between 30 and 45 degrees. This is a modified axial which if the patient is properly positioned will have the same diagnostic value as would be achieved if the patient is supine. The big question many radiographers have about this the axial shoulder view is how to properly position the patient for it. Other issues are what does a properly made radiograph demonstrate, and when should a radiograph be repeated.

Diagnostic Criteria for the Axillary view a.k.a. Craniocaudal Projection

  • The neck and head of humerus is demonstrated in the lateral position. This puts the lesser tubercle anteriorly and profiled.
  • Spine of scapula is demonstrated below the glenohumeral joint. The glenohumeral joint is demonstrated with the superior and inferior borders nearly superimposed. Superimposition of the glenoid fossa is achieved by proper tube angle and proper abduction of the arm. The tube angle should be 25 to 30 degrees directed medial to the lateral body wall. The arm is abducted to 90 degrees in external rotation (15-20 CR angle if the arm is abducted less than 90 degrees).
  • Acromion end of clavicle and AC joint is seen through the humeral head. A crosswise placed grid is used when the inferosuperior measurement is greater than 16 cm. Cassette is aligned perpendicular to the CR and supported with sandbags so the patient is not holding the cassette.
  • To demonstrate a Hills-Sachs defect exaggerate the external rotation pointing the thumb down as it rotates posteriorly.
  • Radiographic exposure must demonstrate good bone and soft tissue detail.
Radiograph #28

image028 What is the anatomical name for the shoulder joint, and name the three indicated structures in your critique of this radiograph?

Critique of Radiograph #28

image028a

    The shoulder joint is termed the glenohumeral joint. The structures at the pointers are A) coracoid process, B) acromion process, and C) glenoid process. Structures that must be seen on a properly penetrated image that has the correct density and contrast are: head of the humerus, glenohumeral joint articulations, glenoid process, coracoid and acromion processes, and lateral extremity of the clavicle. The coracoid process identifies the anterior scapular margin, and the acromion process identifies its posterior margin. These structures must be projected in a manner that allows for assessment of the glenohumeral and acromioclavicular joints for dislocation. The relative position of the humeral head to the coracoid and acromion processes is used to assess joint dislocation and Hill Sachs defect. The glenohumeral joint space is not well visualized, neither is the base of the coracoid relationship to the glenoid cavity. The superior and inferior margins of the glenoid process are not superimposed. Repeating this radiograph to obtain better penetration the shoulder will make this a better radiograph.

Radiograph #29

image029 What is your assessment of this axial view, comment on structures demonstrated, positioning, and radiographic exposure technique?

Critique of Radiograph #29

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    The radiographic technique for this view is superb having good bone penetration, and bone detail. Some structures that are demonstrated are the coracoid process, humeral head, acromion, and glenohumeral joint. The glenohumeral joint articulation is also well demonstrated. The acromion process is superimposed on the glenoid process and the AC joint is not in the center of the humeral head. These findings take away from the overall diagnostic quality of this radiograph. The cause of this improper positioning is failure to fully externally rotate the humerus. On a well-positioned view the base of the coracoid process is aligned with the superimposed superior and inferior margins of the glenoid fossa. The glenohumeral joint should be profiled open, and the entire coracoid process demonstrated. Proper rotation of the humerus will demonstrate the lesser tubercle anteriorly. To demonstrate the rim of the glenoid fossa superimposed the tube is angled 30-35 degrees towards the lateral body wall. The cassette is aligned perpendicular to the central ray. The humerus is properly abducted and is not foreshortened.

Radiograph #30

image030 What is your critique of this axial shoulder radiograph?

Critique of Radiograph #30

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    Sometimes the Axillary view can be difficult to achieve when the patient cannot abduct and externally rotate the arm. Instead, bring the tube close to the body rather than angle into the body to compensate. Keeping the central ray parallel to the glenoid process will help to penetrate the scapula without excessive exposure. This radiograph displays too much of the humerus and too little of the scapula. An improper tube angle has caused the CR to pass through the humerus rather than through the glenoid fossa. This often causes insufficient subject detail and loss of density like what is seen here. This has also resulted in soft tissues overlying the glenohumeral joint and poor penetration of the superolateral scapula. Just a reminder, as the arm is abducted less than 90 degrees the angle CR makes with the body is also decreased. Abduction of 45 degrees would require a CR angle of approximately 20 degrees. The CR should pass through the glenoid process to properly penetrate it. The technologist angled excessively towards the chest wall. The CR should be aligned 30-35 degrees to the lateral body surface when the arm is properly abducted. A grid may be needed to achieve the proper subject contrast.

Radiograph #31

image031 Would you consider this a radiograph that meets the diagnostic standards for the Axillary view, give reasons for your answer?

Critique of Radiograph #31

image031

    While this may seem to be a diagnostic radiograph, it is not. Two things stand out about this radiograph: 1) most of the diagnostic parts of the scapula including the coracoid and glenoid processes are partially omitted, 2) the humerus is in partial external rotation, and 3) the scapula is not penetrated to demonstrate good subject contrast. The relationship of the coracoid base to the glenoid process must be seen in order to properly evaluate the shoulder using this view. There is some foreshortening of the humerus due to flexion of the elbow. The arm should be abducted to 90 degrees to the lateral body wall, or the CR angled about towards the body. Externally rotate the humerus more to project the lesser tubercle anteriorly.

Radiograph #32

image032 In your critique of this radiograph tell whether it meets the diagnostic criteria, but also state what should be done to correctly positioning seen here?

Critique of Radiograph #32

image032

    This radiograph should be rejected because multiple positioning errors are seen. The main errors are the superior and inferior margins of the glenoid process are not superimposed, and a breast shadow obstructs visualization of the coracoid base. The glenohumeral joint is not projected opened as it should be on the craniocaudal view. However, the lesser tubercle is profiled anteriorly as it should be indicating the humerus is correctly positioned in external rotation. The acromion process, lateral clavicle, and AC joint are demonstrated through the head of the humerus. The streaks seen on this radiograph are from the patient’s clothing. Often it is difficult to predetermine what types of clothing will affect a radiograph. If clothing contains logos, silkscreen designs, or thick nylon threading it may cause film artifact. The main reason this radiograph should be repeated is the poor positioning and tube angle. Have the CR enter the glenoid process at about 30 degrees to the lateral body wall.

Radiograph #33

image033 What is your critique of this film, be sure to comment on the exposure technique and positioning?

Critique of Radiograph #33

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    The positioning of this patient may be limited by recent surgical fixation. The technologist acquired this radiograph by abducting the arm as much as possible without causing unnecessary discomfort to the patient. Notice that the acromion and coracoid process are well demonstrated and the proximal humerus is not overly foreshortened. The superior and inferior margin of the glenoid cavity is not perfectly superimposed but is within acceptable limits. The CR is not parallel with the glenohumeral joint space. Improvement in the exposure technique should include use of a grid and using a bit more mAs. The reason being is that the part is well penetrated, but subject detail is lacking. A grid will reduce scatter and add a slightly higher contrast to the radiograph.

Radiograph #34

image034 What is your critique of this radiograph with a history of “s/p surgical fixation” 3 view shoulder to include axial view?

Critique of Radiograph #34

image034

    Postoperative imaging can be challenging especially when the patient has limited mobility. This is a well-positioned radiograph considering the circumstance. Notice the acromion and coracoid processes that are well demonstrated and the cortical margins of the glenoid fossa demarcated. The radiographic exposure technique seen here is superb. The part is well penetrated and the subject contrast is optimal. There is some foreshortening of the humerus but is within acceptable limits. The glenoid fossa is well demonstrated and the fixation screw that edges the joint space is well demonstrated. The entire surgical internal fixation along the acromion process is demonstrated. This is an excellent radiograph that we should all strive to duplicate. The radiographic technique shows good bone subject detail as well as the soft tones like the air shadow over the axilla.

Radiograph #35

image035 What is your critique of this superoinferior axial view taken using an orthopanorex curved cassette?

Critique of Radiograph #35

image035

    This is a well-positioned radiograph with good exposure parameters. Those of us that have used a curved cassette know that it is a nice tool for axial imaging of the shoulder. Several observations make this a good radiograph. The glenohumeral joint articulation is seen, the acromion and AC joint articulation is properly displayed, and the humerus is in external rotation demonstrating the lesser tubercle anteriorly. Overall this is a good radiograph.

Radiograph #36

image036 What is your critique of this radiograph; is it correctly positioned and properly exposed for diagnostic interpretation?

Critique of Radiograph #36

image036a

    This radiograph appears to be diagnostic; however there are a significant positioning errors present. No doubt this radiograph should be repeated. Let’s start with evaluating the coracoid process. It is profiled and its base aligned with the glenoid process, so the arm is properly abducted. Notice that the acromion process is obscured. This is a very important structure for evaluating this view. We have to see it unobstructed or the projection is not diagnostic. It is seen at the lateral end of the clavicle (white arrow) overshadowed by the lesser tubercle. The glenohumeral joint space is demonstrated with the humerus properly articulating with the glenoid fossa. We can see the AC joint and the base of the coracoid process is in line with the glenoid fossa. The positioning here does not show the humerus in full external rotation. The radiographic technique is satisfactory but not optimal. Good subject contrast and trabecular pattern are not well seen although the film has sufficient density. The contrast may yet be too high, but is within acceptable standards.

Radiograph #37

image037 In your critique tell why you think this radiograph taken during an operative shoulder prosthesis placement does or does not meet the diagnostic criteria?

Critique of Radiograph #37

image037

    Because this is an intra-operative film the radiographer had little control over positioning. But what the technologist brings to the team is their ability to manage the tube angle and control subject detail. Although the prosthesis is foreshortened the relationship at the glenohumeral joint is properly displayed. This is because the technologist skillfully aligned the CR perpendicular to the glenoid process. This has opened the glenohumeral joint space and properly displayed the joint articulation. The coracoid process and spine of the scapula are also demonstrated. This radiograph is an example of fully understanding how the axial shoulder view is to be taken and adjusting poor abduction to get a great radiograph.

Radiograph #38

image038 What is your critique of this radiograph considering the injury seen here; is this presentation reasonable for the axial view?

Critique of Radiograph #38

image038a

    This radiograph shows extensive traumatic injury to the shoulder. It is important that we evaluate this radiograph to see if it provides complete information for which this projection is designed. The acromion process and AC joint is well demonstrated but not through the head of the humerus. This is because of the severe dislocation of the glenohumeral joint. A rather large avulsion of the greater tubercle posteriorly is noted. The coracoid is demonstrated through the humeral head indicating this is an anterior dislocation. The presentation of structures seen here is the result of injury not poor positioning. A poor selection of exposure factors contributes to the lack of subject contrast and bone trabecular pattern. Increase the mAs and use a grid to improve subject contrast. Did you notice that this film is presented upside down? The anterior structures should be presented up and the acromion or posterior structures on this film should be hung down.

Summary of the Axillary View critique

  • The entire glenoid fossa, acromion, coracoid process, and humeral head should be visualized. The neck and head of the humerus is demonstrated in the lateral position with the greater tubercle projected anteriorly.
  • The spine of the scapula is demonstrated below the glenohumeral joint and the acromion end of the clavicle and AC joint is seen through the head of the humerus.
  • The superior and inferior rims of the glenoid fossa should be superimposed and the joint space of the shoulder joint opened and in profile.
  • < Soft tissues of the shoulder should be seen.
You should always ask yourself with each image taken, "Did I achieve the diagnostic criteria for this view?" Diagnostic Criteria for the Scapular "Y" View

Glenohumeral joint dislocation is the most common shoulder injury accounting for nearly 95% of shoulder injuries. AC joint dislocation is second, and sternoclavicular joint dislocation is the least likely to occur. The trans-scapular “Y” view is often made as a part of the routine and trauma shoulder series. The “Y” view is also known as the scapulolateral or Mercedes-Benz view. It is the defining view for determining the true position of the humeral head. Dislocation most often occurs from a fall on an abducted externally rotated humerus. A patient who presents with adduction and internal rotation of the humerus is suspect for posterior dislocation. Shoulder injuries often present with obvious deformity of the shoulder. Clinically the patient presents with the arm adducted in external rotation. It is important that the patient is properly positioned and the humerus is placed in correct alignment with the scapula to determine the direction of a dislocation.

The standard AP views may appear relatively normal and difficult to evaluate. The AP view can offer some indications of dislocation. An example is the light bulb sign, which is caused by extreme internal rotation obscuring the greater tuberosity. Another example is the absence of the normal half moon overlap of the humeral head on the glenoid cavity. Whenever there is a question of a possible posterior dislocation the trans-scapular “Y” view is indispensable for determining the position of the humeral head. The arms of the “Y” are formed by the confluence of the coracoid process (anterior arm) and the acromion (posterior arm). The glenoid fossa bridges these two structures and the body of the scapula forms the single long leg of the scapular “Y”. Superimposing the vertebral and axillary borders by rotating the body so that the thoracic cage does not obstruct the scapula achieves the proper display of the scapular “Y.” The arm is dangled freely so that the head and shaft is superimposed on the body of the scapula. Ideally the scapula is in a true lateral position with the medial and lateral borders superimposed. The lateral border is thick and the medial border thin, which are distinguishable on the “Y” view. A normal shoulder presents the head of the humerus directly over the conjoining of the three segments of the “Y.” An anterior dislocation will cause the head to obscure the view of the coracoid process. A posterior dislocation presents with the head of the humerus obscuring the view of the scapular spine and acromion.

The diagnostic criteria for the scapular “Y” view should demonstrate:

  • The entire scapula and proximal humerus in the lateral projection must be demonstrated. The acromion process and coracoid process profiled and the glenoid cavity seen from its face.
  • When properly positioned the relationship of the glenoid cavity and humeral head is viewed from its face. The body of the scapula should be superimposed on the proximal humerus.
  • The exposure technique should penetrate the scapula and humerus so that the rim of the glenoid cavity is seen with good bone detail.
Radiograph #39

image039 Does this radiograph meet the diagnostic criteria for the scapular "Y" View?

Critique of Radiograph #39

image039

    Yes it does meet the diagnostic criteria for the scapula “Y” view. The body of the scapula and humerus are superimposed, as they should be. The acromion and coracoid processes are in profile. The scapula is rotated away from the ribs so there is no overlap of the thoracic cage. Radiographic technique is adequate even though the acromion process is slightly overpenetrated. The angles of the ribs are well penetrated. There is good bone detail around the glenoid cavity. It is well penetrated and its edges are easy to see. Repeating this radiograph is not necessary.

Radiograph #40

image040 What is your critique of this radiograph, tell what direction the patient should be rotated to align the scapula in the true scapular “Y” view?

Critique of Radiograph #40

image040

    The key to understanding how to align the scapula is to look at the vertebral and lateral borders of the scapula. The axillary border has the thick cortex and the vertebral border has the thin cortex. In this picture we can see that the vertebral border is closer to the thoracic cage. This indicates the patient is rotated less than is needed to superimpose the vertebral and axillary borders. To correct this the patient should be rotated more. If the view is taken as an anterior oblique the patient should be rotated more towards the affected shoulder, if PA then towards the unaffected shoulder.

Radiograph #41

image041 What is your critique of this radiograph, tell what direction the patient should be rotated to superimpose the vertebral and axillary borders?

Critique of Radiograph #41

image041

    This radiograph is overexposed and is improperly positioned. It is not easy to find the right radiographic technique that will demonstrate good subject contrast over the entire scapula. For this projection good subject contrast with adequate penetration of the body of the scapula, acromion and coracoid processes is needed. Good bone detail is possible with higher kVp and lower mAs technique. Notice that the acromion process is completely obliterated by the high mAs, high contrast technique. To correct this exposure factures should be adjusted using the 50/15 rule towards lower contrast. As for positioning, the patient should be rotated more towards the unaffected side to align the vertebral and axillary borders. The humerus is correctly place and will be superimposed over the scapula with correct body rotation.

Radiograph #42

image042 What is your critique of this scapula “Y” radiograph, comparing it to the diagnostic criteria state why or why it does not meet the requirements for diagnosis of fracture or dislocation?

Critique of Radiograph #42

image042

This radiograph meets all the requirements for the scapular "Y" view. Even though the coracoid and humerus are projected onto the thoracic cage the scapular body is not. The glenoid process is well demarcated as is the humeral head articulation. The parts of the scapular “Y” are properly demonstrated: the glenoid cavity, coracoid and acromion processes, and body of the scapula. The radiographic exposure technique correctly demonstrates all structures and soft tissues. This is a well penetrated subject using low contrast exposure technique allowing the soft tissue to be visible.

Radiograph #43

image043 Evaluate this radiograph taken for trauma to the scapula somewhere along the body of the scapula; discuss why the “Y” view is not indicated based on this patient’s history?

Critique of Radiograph #43

image043

    This is a true lateral scapula projection not the scapular "Y." For this projection the arm is raised to demonstrate the scapula free of the humerus. The positioning for this projection is very good. The scapula is correctly projected away from the rib cage. I would suggest including the entire superior portion of the scapula. Good collimation is always welcomed; however, excessive collimation like what is seen here may cause you to have to repeat the radiograph. This of course would mean more exposure to the patient. The radiographic technique is adequate for this radiograph.

Radiograph #44

image044 What are your comments on this radiograph, assume it is should be the scapular “Y” projection?

Critique of Radiograph #44

image044

    This radiograph is similar to others we have seen in which the lateral border is rotated away from the thoracic cage. The solution is to oblique the patient more towards the unaffected side to align the scapular borders. The arm should be brought down by the side to superimposing it over the scapula. An optimal exposure technique would demonstrate a well penetrated glenohumeral joint without overexposing the arms of the scapular “Y.” This is a high contrast image indicated by the lack of penetration of the axillary ribs and overexposure of the acromion process. This low kVp high mAs exposure technique. The main purpose for the scapular “Y” projection is to evaluate the shoulder for dislocation. This can be evaluated from this radiograph in spite of the poor positioning and exposure technique. In order to reduce patient exposure this radiograph should not be repeated. But future positioning should attempt to align the scapular borders and shaft of the humerus with the scapula and use a better exposure technique.

Radiograph #45

image045 Use the diagnostic criteria to evaluate this radiograph, what should be done to improve the subject contrast seen here?

Critique of Radiograph #45

image045

    The patient is correctly positioned. The scapular borders are aligned and away from the rib cage; the humerus is superimposed on the scapula. The scapular "Y" is well demonstrated, as is the glenohumeral joint, coracoid and acromion processes. However, the subject lacks penetration throughout the scapula resulting in insufficient subject detail. The contrast scale is again too high representing poorly penetrated bone. Soft tissue structures are obliterated. Good penetration of bone is essential to diagnosing fractures and dislocations. This view should be repeated using more kVp to penetrate the subject. A compensatory decrease in the mAs should be made so that subject contrast is enhanced.

Radiograph #46

image046 Does this radiograph meet the diagnostic criteria; discuss why or why it does not?

Critique of Radiograph #46

image046

    This is a radiograph that meets the diagnostic criteria for the scapular “Y” view. The scapula is slightly rotated with the coracoid process partially superimposed on the thoracic cage; however this does not diminish diagnostic value. The glenohumeral joint is in profile and the acromion and coracoid processes are well seen. A good radiographic exposure technique was used to demonstrate all bony structures of the scapula and humerus. The lateral thoracic wall is well penetrated using low contrast exposure allowing the ribs and lung parenchyma to be evaluated. The avulsion fracture of the humeral head and surrounding soft tissues is optimally demonstrated along with other bone and soft tissue details.

Radiograph #47

image047 What is your assessment of the positioning and radiographic exposure for this scapular “Y” view?

Critique of Radiograph #47

image047

    This is a good place to discuss collimation and patient exposure. Too much of the patient’s body was unnecessarily exposed. This can sometimes occur when using positive beam limiting collimators that open automatically to the size of the cassette. Always practice ALARA using good collimation and exposure technique. The medial, superior, and inferior borders could be more collimated on this patient without compromising area of interest. The positioning is good with minimal foreshortening of the scapula. There is a slight amount of foreshortening of the scapula possible because the patient is kyphotic or due to the midcoronal plane not being vertical and parallel with the image receptor. The CR can be angled 5-10 degrees caudal entering perpendicular to the scapular body. Again we see an example of using low kVp exposure that does not sufficiently penetrate the scapula. Always consider good bone detail and good penetration when choosing an exposure technique.

Radiograph #48

image048 What is your critique of this radiograph with a history of “post-op ORIF left scapula” evaluate alignment of scapula?

Critique of Radiograph #48

image048

    The positioning seen here is good. Notice that the humerus is moved medially to demonstrate the scapula without superimposition of the humeral shaft. Now considering the history of surgical repair of the scapula and the internal fixation demonstrated, the radiograph is flawed in that the inferior angle of the scapula is clipped. This is a post-operative survey film and all of the scapula must be included. The exposure technique is optimal for the scapula. Repeat film to include the entire scapula is recommended.

Radiograph #49

image049 What is your critique of this shoulder radiograph taken for post-operative scapula and humerus repair?

Critique of Radiograph #49

image049

    Here is an example of the radiographer really understanding the rational for the requested study. Notice that the scapula is not projected in a true lateral. This was intentional so that the internal fixation of the scapula does not superimpose that of the humerus. This makes them both easier to evaluate. The ability to evaluate the scapular "Y" is also preserved. Good radiographic exposure is used (low contrast) to penetrate the humerus and the scapula providing good bone and soft tissue detail. An excellent amount of collimation has been applied. This brings out the subject detail and reduced patient dose in keeping with ALARA.

Radiograph #50

image050 What is your critique of this radiograph taken for acute trauma?

Critique of Radiograph #50

image050

    Normally the arm is brought close to 90 degrees to the scapula to demonstrate the scapula without humeral superimposition. In this case the patient has a fracture of the scapula, which makes it difficult to move the arm away from the scapula at all. This is a good radiograph showing the scapula even though the scapula is not in a true lateral. Acute trauma may cause the patient too much pain when the arm is brought across the chest the way it is described in textbooks. A well-made lateral scapula radiograph demonstrates superimposition of the medial and lateral borders without superimposition on the thoracic cavity. But this description does not take into consideration comminuted fractures like the one seen in this radiograph. Most scapular fractures occur at the body or neck. Both of these structures and the fracture are adequately visualized. FYI: The higher the humerus is elevated the less rotating of the patient is needed to place the scapula parallel to the image receptor. This is because the scapula moves laterally with abduction of the humerus. CT is recommended when this type of fracture is seen.

Summary of the scapula "Y" and lateral scapula views

  • Demonstrate the entire scapula in the lateral projection profiling the acromion and coracoid processes.
  • Demonstrate the relationship of the glenoid fossa to the humeral head.
  • The body of the scapula should be superimposed on the proximal humerus when the scapular “Y” is properly demonstrated. Medial and lateral borders of the scapula should be superimposed.
  • Body and neck of the scapula should be well demonstrated with the humerus abducted 90 degrees to the body for the lateral scapula view. This shows the scapula without the humerus being superimposed on it.
  • When the thick border (lateral border) is next to the ribs and the thin border (vertebral border) of the scapula laterally the patient is rotated more than is needed.
  • When the thin border is next to the ribs and the thick border is laterally the patient is not rotated sufficiently to superimpose the borders.
  • Radiographic technique should penetrate the scapula and humerus providing good bone and soft tissue detail.
You should always ask yourself with each image taken, "Did I achieve the diagnostic criteria for this view?" Diagnostic Criteria for the AP and Lateral Proximal Humerus Views

Purpose: To identify fractures involving the extremities or shaft of the humerus and to identify dislocations of the glenohumeral or elbow joints. When a fracture of the proximal humerus is suspected shoulder projections are more appropriate. Likewise, when fracture or dislocation of the elbow is suspected specific projections for the elbow are recommended. The reason being is that the humerus is the longest bone in the upper extremity and the central ray diverges too much to appropriately demonstrate the joints at each end in a single view.

  • The entire humerus and both joints are entirely demonstrated in each view. Sometimes it is necessary to demonstrate the joints formed by the humerus on either the shoulder or elbow views when patient size is a factor.
  • Soft tissues surrounding the humerus should be demonstrated along with good bone detail sufficient to evaluate fractures or dislocations.
  • Positioning for the AP projection places the epicondyles parallel to the image receptor and the greater tubercle profiled laterally.
  • Positioning for the lateral humerus places the epicondyles perpendicular to the image receptor the elbow is in a true lateral and the lesser tubercle is projected medially.
Radiograph #51

image051 What is your critique of this film if the history for exam states trauma to shoulder and proximal humerus, r/o fracture? Is this a good radiograph to evaluate the proximal humerus?

Critique of Radiograph #51

image051

    One of the most common reasons for requesting the entire humerus is the discovery of a fracture either distally or proximally. This shoulder radiograph is an example of why the entire humerus might be requested, especially if there is pain distally. If you discover a fracture like this one it is important that you do not abduct the arm to take an axial view. This could cause damage to arteries and the brachial plexus that lies in the axilla. Do a transthoracic lateral or a "Y" view to complete the series. This view is best described “as is” which is acceptable for trauma when there is obvious deformity of the extremity. Radiographic exposure is proper for this view of the proximal humerus. The entire humerus does not need to be imaged when the physician request the shoulder for possible humerus fracture. This is an excellent radiograph!

Radiograph #52

image052 Discuss the positioning and diagnostic criteria for this radiograph of the humerus?

Critique of Radiograph #52

image052

    The required anatomy is included in this single view. We can see the anatomy from the glenohumeral joint through the elbow joint. The arm is properly rotated with the epicondyles parallel to the image receptor. This was achieved by externally rotating the humerus until an imaginary line connects the humeral epicondyles and is parallel with the image receptor. Proximally the greater tubercle is profiled laterally. The visualized bone is well penetrated. The shoulder could be penetrated more; however, it is within acceptable limits for an underpenetrated radiograph. Try to penetrate both ends using an exposure technique that gives good bone density and soft tissue detail. Using a grid is not necessary when the shaft of the humerus measures less than 14 cm and was not used for this radiograph. The optimum kVp range when not using a grid is 70-80. When the part measures at or greater than 14 cm a grid should be used and a concomitant increase in the kVp is recommended.

Radiograph #53

image053 Discuss the mediolateral projection of the humerus; does it satisfy the diagnostic criteria as demonstrated on this radiograph?

Critique of Radiograph #53

image053

    The mediolateral projection is made with the humerus adducted 90 degrees to the body and the elbow joint flexed to 90 degrees. The forearm is rotated so that the humeral epicondyles are perpendicular to the image receptor. Like the standard lateromedial humerus view the lesser tubercle is profiled. The mediolateral projection allows the humerus to be placed closer to the cassette than is achievable with the lateromedial projection. Either view will profile the humerus in the lateral projection with the lesser tubercle profiled medially. There is adequate bone penetration; however the radiograph does not optimally display bone and soft detail at both extremities. This is a high contrast exposure that shows underpenetration of the shoulder and overexposure of the elbow. You have to be careful when taking this view that the patient does not have a fracture that could damage nerves and blood vessels with this movement. This is not the recommended way to take a lateral projection of the humerus, especially when trauma is involved. This radiograph does meet the diagnostic criteria.

Radiograph #54

image054 What is your critique of this radiograph considering the patient was splinted for possible mid-shaft fracture? What precautions should be taken as you try to meet the diagnostic criteria?

Critique of Radiograph #54

image054

    There is obvious deformity of mid-shaft, therefore, you should always take this type of radiograph in the “as is” position. Forced positioning of mid-shaft fractures may result in radial nerve damage. Not including the entire humerus breaches a diagnostic criterion, which is not acceptable. The best way to include both joints when the arm length is greater than 44 cm is to carefully abduct the arm and position it on the cassette diagonally. At least one inch above shoulder and one inch below the elbow joints must be included on the humerus radiograph. Some orthopedic surgeons may want to see the entire length of the humerus on a single projection. Depending on what type of fixation will be used. In some pre-op scenarios you may only need to include an AP view of the elbow. The radiographic exposure technique seen here is adequate for diagnosis.

Radiograph #55

image055 The patient history for this radiograph was acute trauma. Does this radiograph meet the diagnostic criteria for evaluating the humerus?

Critique of Radiograph #55

image055

    Here is an example of doing everything right to make a good radiograph and one thing prevents it from meeting the diagnostic criteria. In this case the elbow is clipped making the view unacceptable. Our concern here is to reduce radiation exposure to the entire humerus. The repeated view should be collimated to the elbow. Positioning of the elbow appears to have correct alignment with the epicondyles perpendicular to the film. Greater penetration of the proximal humerus would have been optimal; however, it is adequate so long as the AP view is well penetrated.

Radiograph #56

image056 Give your critique of this radiograph of the humerus taken for trauma to the shoulder and elbow. Is this an acceptable radiograph, why or why not?

Critique of Radiograph #56

image056

    Several things stand out about this radiograph, first is that the positioning for this lateral view seems to be well positioned. It may be a good idea to abduct the arm away from the lateral body wall, or move the breast shadow away from the proximal humerus. Secondly, good collimation is always a good idea because it adheres to the principle of ALARA. But in this case the proximal humerus is over collimated. Considering this is a trauma series the entire glenoid process of the scapula should be included. This will allow for evaluation of the glenohumeral joint articulation. Lastly, the exposure technique is incorrect for the humerus. Notice the proximal portion of the humerus is underpenetrated and the inferior distal humerus is over exposed. The cause of this is too high mAs. Adjust the exposure technique using less mAs and greater kVp according to the 50/15 rule. This will give greater penetration of the proximal humerus and lower the contrast in the distal humerus. Combining proper exposure with good positioning will result in a more diagnostic radiograph that has good bone and soft tissue detail.

Radiograph #57

image057 Give your critique of this lateral view of the humerus. History for the exam is postoperative evaluation of internal fixation.

Critique of Radiograph #57

image057

    This is a well-positioned lateral view of the humerus. What makes this a great lateral is that time was taken to get a true lateral view of the elbow. The proximal humerus is properly demonstrated. The radiographic technique is adequate to visualize bone and soft tissue. The subject of the radiograph, the internal fixation device is well penetrated and good contrast between it and bone is displayed. This is a good radiograph meets the diagnostic criteria.

Radiograph #58

image058 This radiograph was taken for possible pathological fracture of the humerus. Special instructions were to not force internal or external rotation. Critique this radiograph based on the history given, special instructions, and diagnostic criteria.

Critique of Radiograph #58

image058

    Considering the pathological fracture of the proximal humerus, the positioning of the elbow for this lateral view is acceptable. This radiograph demonstrates very poor collimation. Always practice ALARA, which in this case does not include the chest and abdomen in the humerus radiograph. This amount of over exposure is unacceptable and should not occur routinely. This amount of open collimation has reduced the subject contrast. Better collimation would give higher subject contrast and less scatter to degrade the image. When using high kVp to achieve uniform density in the subject it is important to use good collimation. This will reduce scatter and give slightly higher contrast to a well penetrated radiograph. Repeating the view is not necessary; however, using less mAs and tighter collimation would have improved this radiograph.

Radiograph #59

image059 This is a serious fracture of the distal humerus. What is your critique of the positioning and exposure technique for this AP view?

Critique of Radiograph #59

image059

    Overall this is a fine radiograph; however, abducting the arm blindly when a patient has obvious deformity is risky and should not be done. Options include taking the radiograph “as is” of the portion of the arm with the deformity, or turn a 14 X 17 cassette aligning the humerus with the corners of the film. In either case only an experienced skilled radiographer should abduct the arm as seen in this radiograph. Do not manipulate either the humerus or the forearm in the process taking radiographs on trauma victims with obvious deformity. Use the x-ray tube to compensate for the AP and lateral views to accomplish the diagnostic criteria. More of the proximal forearm should be included when this type of fracture is demonstrated. You can include it on the crosstable lateral view, or take a separate AP view of the distal humerus and proximal forearm.

Radiograph #60

image061 What is the name of this view of the proximal humerus? State whether the positioning is correct and discuss why it is taken.

Critique of Radiograph #60

image061

    This is a transthoracic lateral view of the humerus. This view is rarely done nowadays because so few technologist and radiologist have seen it often enough. Usually a breathing technique is used to blur the lung shadow. This is a very nice radiograph with just enough of a breathing technique to demonstrate the humerus. The humerus is correctly projected between the sternum and spine. The humerus is in a true lateral with the forearm supinated and the elbow in a true lateral. Radiographic exposure shows good penetration of the chest and humerus. The fracture of the surgical neck is identified and its anterior/posterior displacement can be evaluated. This projection is not recommended routinely because of the additional exposure to the chest. Also, the glenohumeral joint is difficult to see with this view making evaluation of dislocations very difficult.

Summary of the AP and Lateral Views of the Humerus

  • The entire humerus should be demonstrated when it is ordered by a physician. The proximal or distal humerus is demonstrated on either the shoulder or elbow views.
  • Soft tissues surrounding the humerus should be demonstrated along with good bone detail sufficient to evaluate fractures or dislocations.
  • Position for the AP view should have the epicondyles of the humerus parallel to the image receptor, proximal humerus demonstrates the greater tubercle; position for the lateral humerus the epicondyles are perpendicular to the image receptor and the proximal humerus profiles the lesser tubercle.
You should always ask yourself with each image taken, "Did I achieve the diagnostic criteria for this view?"


Summary Points

  • The shoulder girdle is a term referring specifically to the clavicle and scapula. The importance of the shoulder girdle is that it connects the respective upper limb to the trunk.
  • The extremities of the clavicle are named: the lateral end is called the acromial end, the middle portion is called the body, and the sternal end is the medial extremity. It has two articulations, the lateral end forms the acromioclavicular joint (AC joint) and the medial end forms a sternoclavicular joint (SC joint).
  • There are three structures within the scapula’s superior border: the superior angle (a.k.a. medial angle), scapular notch, and coracoid process. The vertebral (medial) border is towards the spine; the lateral (axillary) border is towards the armpit. Neither the vertebral nor the axillary borders have named anatomical structures within them.
  • The anterior surface of the scapula has a rather large broad shallow fossa called the subscapular fossa that houses the subscapularis muscle. This muscle is one of the four rotator cuff muscles.
  • On the posterior surface of the scapula is found a sharp ridge of bone called the spine of the scapula. It divides this surface into a superior fossa called the supraspinatus fossa that houses the supraspinatus fossa, and an inferior fossa called the infraspinatus fossa that houses the infraspinatus muscle. These two muscles are part of the rotator cuff group that rotates the humerus.
  • The long scapular spine ends laterally in an irregular process called the acromion process. The acromion process articulates with the lateral extremity of the clavicle forming the acromioclavicular joint.
  • AC joint dislocations occur from a direct fall on the shoulder or high impact injury with an outstretched arm. Acromioclavicular joint injuries (12% of shoulder injuries) are more frequent than sternoclavicular joint injuries (2-5% of shoulder injuries), and less common than glenohumeral joint injuries (85% of shoulder injuries). A normal width of the AC joint is 7mm in men and 6 mm in women. This distance decreases with age.
  • The glenohumeral joint is the most unstable joint in the body and is therefore frequently radiographed. Most traumatic dislocations are caused by indirect force. Anterior dislocations are the most common occurring about 95% of the time.
  • The most common complication of anterior dislocation is its reoccurrence. Other complications are related to rotator cuff tear and transient nerve injury. This occurs because the neurovascular bundle is stretched during anterior dislocation and the Axillary artery or its branches is injured.
  • An important relationship in the shoulder is that the acromion process is posterior to the glenoid fossa, and the coracoid process is anterior to the glenoid process.
  • Four muscles of the six muscles that join the scapula to the humerus at the shoulder joint are called the rotator cuff muscles. They are the subscapularis, supraspinatus, infraspinatus, and teres minor.
  • The glenoid cavity articulates with the head of the humerus. This articulation attaches the upper appendage to the shoulder girdle. Movement of the entire upper extremity occurs through the many motions of the glenoid fossa and head of the humerus called the glenohumeral joint (a.k.a. shoulder joint).
  • Three structures form the scapula “Y.” The arms are formed by the coracoid and acromion processes, the leg is formed by the body of the scapula.
  • A well-positioned, well-collimated AP radiograph demonstrates the lateral two-thirds of the clavicle, glenohumeral joint and upper scapula and proximal humerus. Trauma shoulder views should include the entire clavicle, entire scapula, and proximal humerus.
  • For the craniocaudal view the spine of scapula is demonstrated below the glenohumeral joint. Acromion end of clavicle and AC joint is seen through the humeral head.
  • The internal rotation film is taken with the epicondyles of the humerus perpendicular to the tabletop. Internal rotation of the humerus profiles the lesser tubercle medially. The external rotation film is taken with the epicondyles parallel to the tabletop. External rotation of the humerus projects the greater tubercle laterally.
  • The purpose of the Grashey view is to demonstrate the glenoid process in profile and the glenohumeral joint space open. The Grashey view places the patient in an oblique position in order to accomplish this. A well-positioned Grashey view will profile the glenoid process, coracoid process, and the glenohumeral joint space.
  • The craniocaudal projection is especially important because it can help demonstrate a type of depression fracture not commonly seen on other shoulder views called the Hill-Sachs defect. This projection demonstrates anterior and posterior dislocations of the glenohumeral joint. Posterior dislocations of the humeral head are particularly difficult to diagnose from the AP views. Proper positioning of the arm in abduction will demonstrate the lesser tubercle anteriorly and the posterolateral humeral head in profile. Proper positioning of the arm for the craniocaudal projection is in external rotation.
  • When taking the craniocaudal shoulder projection foreshortening of the humerus occurs when the arm is less than 90 degrees to the body, and is pronounced at 45 degrees. For example, when the arm is abducted 45 degrees to the body the CR is correspondingly angled 20 degrees.


Copyright image Copyright 2007 Nicholas Joseph Jr.




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