Humerus AP is a radiography positioning projection of the Upper Extremity. Upright, arm at side with elbow flexed 90 degrees, palm inward. SID 40". The centering point is located at the midpoint of the humerus between shoulder and elbow.. The central ray is perpendicular to ir at the midpoint of the humerus.. Image-quality criteria include entire humerus visible from shoulder to elbow., humeral head, shaft, and condyles all included.. Standard exposure ranges from 70 to 80 kVp, 3 to 6 mAs, at an SID of 40 inches (102 cm).
Anatomy demonstrated
- Humeral head, neck, and shaft.
- Greater and lesser tuberosities.
- Medial and lateral epicondyles.
- Distal humerus and trochlea.
- Shoulder articulation and glenoid fossa.
- Proximal radius and ulna.
Patient preparation
- Verify patient identity using two identifiers.
- Remove watches, bracelets, and radiopaque items from the arm.
- Position patient upright facing forward.
- Keep arm at the side with elbow flexed 90 degrees.
- Place hand with palm facing inward on the abdomen or lateral thigh.
Position & centering point
At the midpoint of the humerus between shoulder and elbow.
Central ray
Perpendicular to IR at the midpoint of the humerus.
Exposure / technique
- kVp
- 70–80
- mAs
- 3–6
- SID
- 40" (102 cm)
- Notes
- Grid recommended for adult patients.
Image-quality criteria
- Entire humerus visible from shoulder to elbow.
- Humeral head, shaft, and condyles all included.
- Minimal rotation with epicondyles symmetric.
- Shoulder articulation and upper arm well visualized.
- Bone trabeculae sharp, no motion blur.
- Collimation: 1 inch above shoulder, 1 inch below elbow.
Common errors / ARRT traps
- 1 Internal rotation superimposes the greater tuberosity.
- 2 External rotation superimposes the lesser tuberosity.
- 3 Off-center CR clips the proximal humerus or distal elbow.
- 4 Lifting the shoulder rotates the arm.
Clinical indications
- Trauma evaluation for humeral fracture.
- Suspected proximal humerus fracture.
- Shoulder dislocation assessment.
- Post-operative follow-up of humeral fixation hardware.
Aligned to the 2025 ARRT Content Specifications.