Subscapularis

Musculus subscapularis

MuscularDeep musclesThoraxLeft and right

View left in 3D View right in 3D

What it is
The largest rotator-cuff muscle: a triangular sheet filling the subscapular fossa on the rib-facing surface of the scapula, converging onto the lesser tubercle of the humerus in front of the shoulder joint.
Function
Medially rotates the arm and prevents forward dislocation of the humeral head.
Size
About 15 cm long; fan ~10 cm wide.
Clinical note
Tested with the "lift-off" and "belly-press" tests; it glides on serratus anterior across the scapulothoracic space.

Nearby muscular structures Caval opening of the diaphragm, Infraspinatus, Pectoralis major, Pectoralis minor, Rhomboid major, Rhomboid minor, Serratus anterior, Supraspinatus, Teres major, Teres minor