The subscapularis tendon inserts broadly on the lesser tubercle, covering the anterior humeral neck and blending with the anterior capsule. It is the largest rotator cuff tendon and the primary anterior humeral head stabiliser. Subscapularis tears are significantly underdiagnosed relative to supraspinatus tears because they require dedicated axial shoulder MRI views and specific examination tests. Upper subscapularis tears from anterior shoulder dislocation in young patients require repair to restore anterior stability.
Internal rotation force transmission; anterior glenohumeral stabilisation against dislocation
The lift-off test (hand behind the back lifted away from the lumbar spine against resistance) and the belly-press test (pressing the palm against the abdomen and maintaining the wrist extended) are the specific clinical tests for subscapularis integrity. Medial biceps tendon subluxation out of the bicipital groove is highly associated with upper subscapularis tears because the subscapularis forms the medial wall of the bicipital groove. Arthroscopic subscapularis repair is technically demanding but produces equivalent outcomes to open repair in experienced hands.
Anterior cuff disruption producing positive lift-off and belly-press tests with associated medial biceps instability, requiring arthroscopic repair especially in young patients with anterior dislocation mechanism.
