Shoulder
Standard radiographs
Shoulder injury:
▪ The AP view is standard in all departments.
▪ The precise second view will vary.
□ We prefer the apical oblique projection (aka Modified Trauma Axial, MTA; see p. 76), because it allows gentle positioning of the patient, provides excellent demonstration of dislocations and shows fractures extremely well1,2.
□ Second best: the scapula Y lateral (see p. 77). The patient is comfortable as the arm is not moved, and a true scapula Y lateral will show posterior dislocations3. But this view must be technically very precise, and fractures can be difficult to identify.
Suspected fracture of the clavicle:
Note our descriptive emphasis in this chapter
We are strong advocates that the second view for an injured shoulder should be the apical oblique radiograph rather than any alternative second view. Consequently, our descriptions concentrate mainly on the AP view and the apical oblique view of the injured shoulder.
Normal anatomy
AP view
The normal humeral head does not appear round and symmetrical. Its shape mimics the head of an old fashioned walking stick. This is due to the radiographer positioning the humerus in external rotation.
The articular surfaces of the glenoid and the humerus parallel one another.
The inferior cortex of the lateral part of the clavicle aligns with the inferior cortex of the acromion process. There is no step between these cortices.
Lateral scapula view—ie the Y view3
The humeral head overlies the centre of the glenoid. The Y is formed by the junction of the scapular blade, the coracoid and the spine of the scapula. On this view anterior is towards the ribs and posterior is away from the ribs.
Analysis: the checklists
The AP radiograph
Ask yourself five questions.
1. Is the humeral head lying directly below the coracoid process?
2. Does the humeral head have a walking stick shape, and does its articular surface parallel the glenoid margin?
No = use the second view to rule out a posterior dislocation.
3. Is the acromioclavicular joint normal—ie do the inferior cortices of the clavicle and acromion process align?
No = subluxation or dislocation at the acromioclavicular joint.
4. Is the coracoclavicular distance more than 1.3 cm?
Yes = stretching or rupture of the coracoclavicular ligaments (see p. 86).
Apical oblique view1,2
Ask yourself three questions.
1. Do the articular surfaces of humerus and glenoid lie immediately adjacent to each other—ie does the centre of the triangle base line up with the centre of the glenoid articular surface?
No = a glenohumeral joint dislocation or subluxation.
2. Is there a fracture of the head or the neck of the humerus?
The apical oblique view is excellent in demonstrating a posterior dislocation at the glenohumeral joint.
This radiograph shows a posterior dislocation. The two drawings illustrate how an inexperienced observer can readily detect the abnormal alignment on the radiograph.
See p. 76 for the expected normal alignment on an apical oblique view.
The common fractures4–9
Greater tuberosity of the humerus
Often undisplaced and is then very subtle (arrow). Examine the AP view very carefully.
Occasionally these fractures are invisible on the plain radiographs.
Humeral head and/or rim of the glenoid
A recognised complication of an anterior dislocation.
This apical oblique view shows the abnormal articular surface of the humeral head with a fragment (arrowhead) adjacent to it; a defect in the rim of the glenoid is also present (arrow). The glenohumeral articulation is normal.
