Shoulder AP is a radiography positioning projection of the Upper Extremity. Erect, arm at side with slight external rotation. SID 40". The centering point is located shoulder joint, approximately 1 inch below the coracoid process.. The central ray is perpendicular to the shoulder joint.. Image-quality criteria include shoulder joint space visible and open without superimposition., proximal humerus, scapula, and clavicle all included.. Standard exposure ranges from 70 to 80 kVp, 6 to 12 mAs, at an SID of 40 inches (102 cm).
Anatomy demonstrated
- Proximal third of the humerus.
- Glenoid cavity and fossa.
- Humeral head and neck.
- Coracoid process projecting anteriorly.
- Acromioclavicular joint.
- Scapula in profile.
Patient preparation
- Verify patient identity using two identifiers.
- Remove watches, bracelets, and radiopaque items from the shoulder.
- Position patient erect facing the IR.
- Place arm at side with palm turned slightly outward for external rotation.
- Keep shoulders level and relaxed.
Position & centering point
Shoulder joint, approximately 1 inch below the coracoid process.
Central ray
Perpendicular to the shoulder joint.
Exposure / technique
- kVp
- 70–80
- mAs
- 6–12
- SID
- 40" (102 cm)
- Notes
- Erect technique. Slight external rotation opens the shoulder joint.
Image-quality criteria
- Shoulder joint space visible and open without superimposition.
- Proximal humerus, scapula, and clavicle all included.
- Coracoid process visible projecting anteriorly.
- Glenoid cavity fossa visualized in profile.
- No rotation; scapula and humerus symmetric.
- Collimation: 3 inches on all sides of the shoulder joint.
Common errors / ARRT traps
- 1 Internal rotation medially rotates the humerus off true AP.
- 2 Excess external rotation shifts the proximal humerus anterior.
- 3 Patient slouching or rotating forward closes the shoulder joint.
- 4 Off-centered CR clips the coracoid or proximal humerus.
- 5 Inadequate collimation includes excessive scapula or arm.
Clinical indications
- Suspected shoulder dislocation or subluxation.
- Proximal humeral fracture evaluation.
- Rotator cuff or soft-tissue injury assessment.
- Shoulder joint degenerative changes or arthritis.
Aligned to the 2025 ARRT Content Specifications.