AC Joints AP with Weights

• Bilateral acromioclavicular joints under gravitational stress.
• Distal third of both clavicles.
• Coracoclavicular space, widened with complete ligament tear.
• Lateral aspects of both scapulae.
• Coracoid processes bilaterally.
• Proximal humeral heads.

• Verify patient identity using two identifiers.
• Remove watches, bracelets, and radiopaque items from both arms.
• Position patient erect facing the IR with shoulders level.
• Attach 5 to 10 lb weights to each wrist via wrist straps.
• Have the patient relax shoulders and let the weights hang freely.

Midline at the AC joint level, with weights suspended from both wrists by straps.

Perpendicular to the midline at the level of the AC joints.

kVp

65–75

mAs

5–8

SID

72" (183 cm)

Notes

Pair with the non-weighted AP for direct comparison. Weights must hang freely from wrist straps, never held in the hands.

• Both AC joints visualized side-by-side for direct comparison.
• AC joint space clearly demonstrated, widened if ligaments are torn.
• Distal clavicles and lateral scapulae fully included.
• Clavicles in a horizontal plane, symmetric across midline.
• No rotation; both shoulders equidistant from the spine.
• Collimation: 1 inch above and below the AC joints.

1. 1 Patient holding the weights in the hands instead of letting them hang.
2. 2 Uneven weight load tilts one shoulder higher than the other.
3. 3 Patient leaning forward or backward reduces the gravitational stress.
4. 4 Wrist straps too loose let the patient bear part of the weight.
5. 5 Off-centered CR clips one AC joint at the film edge.

• Suspected AC joint separation (grade II or III).
• Confirmation of complete coracoclavicular ligament tear.
• Comparison study after acute shoulder trauma.
• Pre-operative grading of AC joint dislocation.