A "partial thickness" tear, or incomplete tear, may only require debridement or removal of damaged tissue. The type of surgical repair depends on the type of tear. Therefore, surgery is indicated if nonsurgical treatment fails and the patient experiences persistent pain or weakness or if optimal function of the arm is required for overhead work or sports. Ī rotator cuff tear, including a tear to the teres minor, will not heal without surgery however, good function of the affected shoulder can often be gained non-surgically. The subscapularis, along with the teres major, which is another intrinsic muscle that is not part of the rotator cuff, and extrinsic muscles like the pectoralis major and latissimus dorsi, are responsible for medial, or internal, rotation of the arm. The infraspinatus and teres minor both aid in lateral or external rotation of the arm at the shoulder.
The supraspinatus is responsible for the first 15 degrees of abduction the deltoid, an intrinsic muscle of the shoulder that is not a rotator cuff muscle, is responsible for abduction from 15 to 90 degrees. Each muscle also helps with certain movements of the arm. Ĭollectively, the rotator cuff stabilizes the glenohumeral joint, which is a far more shallow and unstable ball-and-socket joint than the hip. The subscapularis arises from the subscapular fossa of the anterior scapula and inserts on the lesser tubercle of the humerus. The supraspinatus, infraspinatus, and teres minor all arise from the posterior scapula and insert onto the greater tubercle of the humerus. The rotator cuff is comprised of four muscles: supraspinatus, infraspinatus, teres minor, and subscapularis. Along its route, the posterior humeral circumflex artery supplies the teres minor. Then the artery moves anteriorly around the surgical neck of the humerus to supply the shoulder joint. It travels posteriorly with the axillary nerve through the quadrangular space, bounded by the teres minor superiorly, teres major inferiorly, the surgical neck of the humerus laterally, and the long head of the triceps brachii medially. The posterior humeral circumflex artery is a more distal branch off of the third portion of the axillary artery. Along its route, the circumflex scapular artery supplies the teres minor. It moves cranially through the triangular space, created by the teres minor superiorly, teres major inferiorly, and long head of the triceps brachii laterally, into the infraspinatus fossa where it joins the scapular anastomosis. The circumflex scapular artery travels around the lateral border of the scapula between the subscapularis and teres minor. It travels caudally before dividing into two arteries: the circumflex scapular and the thoracodorsal. The subscapular artery is the largest branch off of the axillary artery. The subscapular artery and the posterior circumflex humeral artery arise from the third, most distal portion of the axillary artery. The teres minor is supplied by the subscapular artery and one of its branches, the circumflex scapular artery, as well as the posterior circumflex humeral artery. As a lateral rotator, the teres minor is an antagonist muscle to medial rotation therefore, the teres minor is especially critical in stabilizing the shoulder during medial rotation to prevent anterior dislocation of the humerus. The teres minor also laterally or externally rotates the arm at the shoulder joint. The teres minor is deep to the deltoid muscle.Īs a rotator cuff muscle, the teres minor stabilizes the ball-and-socket glenohumeral joint by helping hold the humeral head (ball) into the shallow glenoid cavity of the scapula (socket). In anatomical position, the long head of the triceps brachii muscle is oriented perpendicular to the teres minor and inferior to it. The teres minor lies inferior to the infraspinatus and superior to the teres major all three muscles have a similar oblique orientation. The lower fibers of the muscle insert directly into the humerus, just below the greater tubercle. The upper fibers of the muscle culminate in a tendon that inserts onto the greater tubercle of the humerus-the tendon blends into the capsule of the shoulder joint. The teres minor arises from the posterior surface of the scapula, directly adjacent to the upper part of its lateral border.