The anatomical basis of the resisted supination external rotation test for superior labral anterior to posterior lesions.

The majority of clinical tests used to diagnose superior labral anterior to posterior (SLAP) lesions of the shoulder have poor diagnostic accuracy, possibly related to a lack of anatomical validity for test procedures. The resisted supination external rotation (RSER) test is suggested to reproduce symptoms associated with a SLAP lesion by placing stress on the labrum through increasing tension in biceps brachii long head. The test requires supination of the forearm against resistance, while the shoulder is externally rotated passively.