Execution
- 1Position the patient standing or sitting with the arm relaxed by the side.
- 2Grasp the forearm below the elbow.
- 3Apply a distal traction force to the arm.
- 4Observe for a sulcus or depression inferior to the acromion.
- 5Repeat in different rotation or abduction positions if the history suggests position-specific instability.
Positive outcome
A visible or palpable sulcus inferior to the acromion is positive for inferior laxity. Magee notes it should be considered positive for instability only when it is symptomatic, unilateral / asymmetric, or associated with a feeling of subluxation.
Studies
| Study | Reliability | Sn | Sp | LR+ | LR− |
|---|---|---|---|---|---|
| Magee eAppendix summary | inter-examiner κ 0.03-0.06; intra-examiner κ 0.01-0.20 | 17-90 | 85-93 | 0.56-2.5 | 0.9-1.1 |
CommentA sulcus sign alone can reflect laxity rather than symptomatic instability, especially if bilateral. Symptom reproduction and clinical history are essential. Reliability and likelihood ratios are not strong enough for the test to stand alone diagnostically.
Low Clinical Value