If the shoulder is neutrally rotated ( elbows pointing outward then towards the scapulae as they lift ) the posterior deltoid will be assisted in this transverse extension by the lateral rotators of the rotator cuff : the infraspinatus and teres minor.
22.
The muscles of the rotator cuff include the subscapularis ( which protects the front of the joint ), and the infraspinatus and teres minor ( which work to externally rotate the humerus against the pull of the pectoralis and coracobrachialis ).
23.
It is strengthened, above, by the Supraspinatus; below, by the long head of the Triceps brachii; behind, by the tendons of the Infraspinatus and Teres minor; and in front, by the tendon of the Subscapularis.
24.
Muscles which attach to the scapulae that adduct and extend the arm include the posterior deltoid muscles, the teres major, and minor stabilizing contribution from some rotator cuff muscles ( infraspinatus and teres minor as lateral rotators, subscapularis as medial rotators ).
25.
The distal attachments of the three rotator cuff muscles that insert into the greater tubercle of the humerus can be abbreviated as SIT when viewed from superior to inferior ( for supraspinatus, infraspinatus, and teres minor ), or SITS when the subscapularis muscle, which attaches to the lesser tubercle of the humerus, is included.
