What type of X-ray series should I order for a possible right shoulder injury?

Standard Shoulder Trauma X-ray Series

For a possible right shoulder injury, order a minimum 3-view trauma series: anteroposterior (AP) views in both internal and external rotation PLUS an axillary or scapular Y view. 1

Essential Radiographic Views

Mandatory Three-View Series

• AP views in internal and external rotation are the foundation of shoulder trauma imaging, detecting approximately 88% of injuries 1, 2
• Axillary or scapular Y view is absolutely vital as the third orthogonal view, because glenohumeral dislocations are routinely misclassified on AP views alone 1, 3
• Posterior dislocations are missed in over 60% of cases when only AP views are obtained, making the orthogonal view non-negotiable 1, 3

Why the Axillary/Y View Cannot Be Skipped

• The axillary or Y view definitively shows the relationship between the humeral head and glenoid, which AP views cannot reliably demonstrate 3
• This view is critical for identifying both anterior and posterior dislocations, as well as associated fractures like Hill-Sachs deformities and glenoid rim fractures 1, 4
• Attempting any intervention without confirming proper glenohumeral alignment could worsen a fracture-dislocation 3

Practical Imaging Protocol

Standard Trauma Series Components

• Grashey projection (true AP of glenohumeral joint) 3
• Axillary lateral view or scapular Y view 1, 3
• AP in internal rotation 1
• AP in external rotation 1

Patient Positioning Considerations

• Obtain radiographs upright rather than supine whenever the patient's condition permits, as shoulder malalignment can be underrepresented on supine imaging 3
• If the patient cannot tolerate an axillary view due to pain, the scapular Y view is an excellent alternative that is better tolerated by 81% of patients 5

When to Add Advanced Imaging

CT Without Contrast Indications

• Order CT if radiographs are equivocal or don't clarify the injury pattern 3
• CT is superior for characterizing complex fracture patterns, especially scapular or proximal humerus fractures when surgical planning is needed 1
• CT definitively identifies posterior dislocations and reverse Hill-Sachs defects (anteromedial humeral head compression fractures) that may be subtle on plain films 1

CT Angiography (CTA) Indications

• Immediately order CTA if any signs of vascular compromise exist: diminished pulses, expanding hematoma, bruit, or associated proximal humeral fractures 1, 3
• Axillary artery injury can occur with shoulder trauma, and delays in recognition significantly worsen outcomes 3

MRI Without Contrast Indications

• Order MRI if radiographs show dislocation and you need to assess soft tissue injuries (rotator cuff tears, labral injuries, capsular tears) in the acute setting 1
• In older patients (>40 years), maintain high suspicion for associated rotator cuff tears even if the bony injury appears minor 1, 3
• If pain persists beyond 2-3 weeks with noncontributory radiographs, MRI is rated "usually appropriate" (9/9) by the American College of Radiology for evaluating occult soft tissue injuries 3

Critical Pitfalls to Avoid

Imaging Errors

• Never rely on AP views alone—this is the most common cause of missed posterior dislocations 1, 3
• Failure to obtain proper orthogonal views (axillary or Y) may lead to missed diagnosis of dislocation in up to 60% of posterior cases 1
• Do not attempt reduction without radiographic confirmation, as this could worsen fracture-dislocations 1, 3

Clinical Assessment Errors

• Always assess for neurovascular compromise at initial presentation and after any intervention 1, 3
• In older patients, don't overlook associated rotator cuff tears, which are commonly missed and impact long-term function 1, 3
• Delaying reduction increases the risk of complications including neurovascular compromise 1