Scapula AP is a radiography positioning projection of the Upper Extremity. Erect, arm abducted 90 degrees. CR perpendicular to midscapula. SID 40". The centering point is located midscapular region, with the arm abducted 90 degrees to draw the scapula laterally.. The central ray is perpendicular to the midscapular area.. Image-quality criteria include entire scapula visualized without rib superimposition., scapular body, spine, and acromion process clearly seen.. Standard exposure ranges from 70 to 80 kVp, 8 to 15 mAs, at an SID of 40 inches (102 cm).
Anatomy demonstrated
- Entire scapular body.
- Scapular spine.
- Acromion process.
- Coracoid process.
- Subscapular fossa.
- Glenoid cavity.
Patient preparation
- Verify patient identity using two identifiers.
- Remove watches, bracelets, and radiopaque items from shoulder.
- Position patient erect facing the IR.
- Abduct the arm of the affected side to 90 degrees from the body.
- Relax shoulders and straighten spine.
Position & centering point
Midscapular region, with the arm abducted 90 degrees to draw the scapula laterally.
Central ray
Perpendicular to the midscapular area.
Exposure / technique
- kVp
- 70–80
- mAs
- 8–15
- SID
- 40" (102 cm)
- Notes
- Erect technique. Abducting the arm 90 degrees draws the scapula laterally, clearing it from the rib cage.
Image-quality criteria
- Entire scapula visualized without rib superimposition.
- Scapular body, spine, and acromion process clearly seen.
- Scapula rotated laterally clear of the lateral thorax.
- Coracoid process visible projecting anteriorly.
- No foreshortening of the scapular body.
- Collimation: 12 inches above shoulder, 15 inches below scapula.
Common errors / ARRT traps
- 1 Failure to abduct the arm 90 degrees leaves the scapula over the ribs.
- 2 Superimposition of ribs obscures scapular detail.
- 3 Patient rotation closes the scapula into the thorax.
- 4 Off-centered CR misses the scapular body or acromion.
- 5 Incomplete arm positioning leaves scapula foreshortened.
Clinical indications
- Scapular fracture evaluation across entire bone.
- Scapular body or spine fracture assessment.
- Rotator cuff or soft-tissue injury evaluation.
- Post-operative scapular fixation follow-up.
Aligned to the 2025 ARRT Content Specifications.