Glenohumeral joint alignment
- Look for well-approximated articular surfaces on all views without abnormal narrowing or asymmetry.
- *Can be affected by technique
- Glenohumeral distance usually <6 mm.
- Acromiohumeral interval usually 7-12 mm
- Look specifically for signs of anterior or posterior glenohumeral dislocation, most easily identified on axillary or scapular y-view
Anterior glenohumeral dislocation
- Humeral head displaced medially on frontal view overlying the glenoid and/or coracoid
- Look closely for signs of Hill-Sachs impaction fracture at posterior/superior humeral head and osseous Bankart injury at anterior/inferior glenoid, often better characterized on post-reduction radiographs
FINDINGS: Interval reduction of anterior shoulder dislocation with apposition of humeral head within the glenoid cavity. Hill-Sachs impaction fracture at the posterolateral aspect of humeral head. Irregular cortical defect extending along the anterior inferior glenoid rim with adjacent mildly displaced osseous Bankart fracture measuring approximately 2 x 4 mm.
Posterior glenohumeral dislocation
- Humeral head with fixed internal rotation and resultant “light bulb” morphology on frontal view
- Look for reverse Hill-Sachs impaction fracture at anterior/medial humeral head (i.e. trough sign) and reverse Bankart fractures at posterior glenoid, often better characterized on post-reduction radiographs
FINDINGS: Posterior dislocation of humerus which remains engaged with the posterior glenoid reverse Hill-Sachs impaction fracture at the anteromedial aspect of the humeral head.
Proximal Humerus Fracture
- A common system for classifying proximal humerus fractures is the Neer classification. While we don't expect you to classify each fracture, it is good form to describe fractures as they relate to this system.
- Neer subdivides the humerus into 4 parts:
- Greater tuberosity
- Lesser tuberosity
- Articular segment
- Humeral shaft
Superior displacement of the clavicle with widening of the coracoclavicular distance, consistent with type III AC joint injury.
Acromioclavicular joint alignment
- Assess the acromioclavicular (AC) distance (normal 5-8 mm)
- Assess the coracocalvicular (CC) distance (normal 10-13 mm)
- Classification of AC joint injury
- Type I- no radiographic findings
- Type II- AC ligament disruption with mild elevation of clavicle (<1 clavicle width) and intact CC ligament (CC distance <13mm)
- Type III- AC and CC ligament disruption with elevation of clavicle relative to acromion (>1 clavicle width)
- Type IV- AC and CC ligament disruption with posterior displacement of clavicle relative to acromion into trapezius muscle
- Type V- AC and CC ligament disruption with severe elevation of clavicle relative to acromion (>2 clavicle width)
- Type VI- AC and CC ligament disruption with inferior subcoricoid dislocation
Example report negative for traumatic injury
FINDINGS:
No acute fracture or dislocation. The acromioclavicular joint is congruent. The visualized lungs are clear.
IMPRESSION:
No acute fracture or dislocation.