The scarf test, also known as the cross-body adduction test, is used to assess the integrity of the acromioclavicular (AC) joint.
The test is performed by passively bringing the patient's arm into 90 degrees of forward flexion, with their elbow also flexed to 90 degrees. The examiner then horizontally adducts the flexed arm across the patient's body, bringing their elbow towards the contralateral shoulder .
This position results in compression of the medial acromial facet against the distal clavicle to provoke symptoms at the acromioclavicular joint .
This test is considered positive if the maneuver successfully reproduces the patient's symptoms of pain localized over the AC joint .
A positive test is usually suggestive of AC joint osteoarthritis or a ligamentous injury to the AC joint (i.e., ligament sprain or joint separation).
The diagnostic accuracy of this test for AC joint pathology is the following:
Currently, research supports special interpretation of a number of different tests performed in a physical examination to render a diagnosis of painful AC joint dysfunction . The following is a summary:
- Ruling out painful AC joint dysfunction: Negative findings on the cross-body adduction test, tenderness on palpation of the ACJ, and Paxinos sign 
- Ruling in painful AC joint dysfunction: Positive findings on the cross-body adduction test, active compression test, and the AC resisted extension test .
Reproduction of pain with the cross-body adduction maneuver may also occur in conditions such as posterior capsule tightness and subacromial impingement.
- Park HB, Yokota A, Gill HS, El Rassi G, McFarland EG. Diagnostic accuracy of clinical tests for the different degrees of subacromial impingement syndrome. JBJS. 2005 Jul 1;87(7):1446-55.
- Huijbregts PA. Concurrent Criterion-Related Validity of Acromioclavicular Joint Physical Examination Tests: A Systematic Review.
- Owens BD. Acromioclavicular joint injury [Internet]. Medscape; 2018 [cited 2020 Dec07]. Available from: https://emedicine.medscape.com/article/92337-clinical#b3