Role of Axillary View and Scapula Y View in Diagnosing Shoulder Dislocation
The axillary view and scapula Y view are essential radiographic projections for accurately diagnosing shoulder dislocations, with the axillary view being superior for detecting anterior-posterior dislocations and the scapula Y view being better tolerated by patients while providing similar diagnostic accuracy. 1, 2
Diagnostic Value of Each View
Axillary View
- Provides a true tangential projection of the glenoid articular surface 3
- Superior for visualizing:
- The relationship between the humeral head and glenoid fossa
- Hill-Sachs lesions (posterolateral humeral head compression fractures)
- Bankart lesions (anterior-inferior glenoid rim fractures) 4
- Critical for detecting posterior dislocations, which are frequently missed on standard anteroposterior views 5
- Shows the position of the humeral head relative to the glenoid in the axial plane
Scapula Y View
- Named for its Y-shaped appearance (formed by the scapular body, acromion, and coracoid process)
- Provides an orthogonal view to the anteroposterior projection
- Demonstrates anterior or posterior displacement of the humeral head
- Generally better tolerated by patients with acute shoulder injuries (81% of patients preferred this view due to less pain) 6
- Easier to obtain technically in trauma settings 6
Clinical Application
The American College of Radiology recommends that a good shoulder trauma radiography protocol includes:
- Anteroposterior (AP) view
- Grashey view (true AP of glenohumeral joint)
- Axillary and/or scapular Y projections 1, 2
Diagnostic Accuracy Comparison
- In 92% of cases, both views provide the same diagnosis 6
- In 8% of cases, the axillary view may miss the correct diagnosis compared to the scapula Y view 6
- For posterior dislocations specifically, the axillary view is considered essential and should be included in the standard protocol 5
Special Considerations
When to Use Both Views
- When clinical suspicion for dislocation exists but initial views are inconclusive
- In cases of seizure, electrocution, or similar trauma where posterior dislocation is suspected 5
- When evaluating for associated injuries (fractures, Hill-Sachs lesions, Bankart lesions)
Common Pitfalls
- Soft tissue shadows can interfere with appreciation of the glenohumeral joint line on axillary views 3
- Mistaking the superior margin of the glenoid as the entire articular surface 3
- Failing to obtain an axillary view in cases of suspected posterior dislocation (commonly missed diagnosis) 5
Practical Approach to Shoulder Dislocation Imaging
- Start with standard AP view (detects 88% of injuries) 7
- Add both axillary and scapula Y views when:
- Dislocation is suspected clinically
- AP view is normal but symptoms persist
- Patient history suggests posterior dislocation (seizure, electrical injury)
- Consider additional specialized views for specific pathologies:
The combination of these views provides complementary information, maximizing diagnostic accuracy while minimizing patient discomfort.