ROTATOR CUFF MUSCLES:

ROTATOR CUFF MUSCLES: (acronym SITS) Subscapularis, Infraspinatus, Teres minor, Supraspinatus SUBSCAPULARIS MUSCLE

ACTION: internally rotates the humerus REFERRAL: posterior shoulder and wrist COMMENTS: this "rotator cuff" muscle attaches to the anterior part of the scapula. It lies between the scapula and the rib cage. Distally it attaches to the anterior part of the humerus, just next to the pectoralis major attachment. This attachment is normally a little tender. You can evaluate if this muscle is strained by internally rotating the arm against resistance. Note that this muscle refers pain to the back of the shoulder. When evaluating the rotator cuff, include this muscle.

INFRASPINATUS MUSCLE

ACTION: external rotation of humerus REFERRAL: upper back, anterior shoulder COMMENTS: This muscle can also refer pain into the vertebral border of the scapula. This muscle has a large attachment and is fairly thin. Because of this, it is normal for it to be a little tender when compressed against the scapula. The lateral trigger point shown refers pain to the anterior shoulder. In sports this muscle becomes strained because its action of decelerating a throwing motion, or racquet swing. It is one of the 4 rotator cuff muscles.

TERES MAJOR AND TERES MINOR MUSCLES

ACTION: Minor- externally rotates humerus. Major- adduction and internally rotates humerus REFERRAL: Minor- posterior shoulder. Major- lateral shoulder. COMMENTS:  The teres minor is the little helper of the infraspinatus. It attaches just next to it on the posterior humerus, and helps external rotation. When strained, people feel a deep ache the size of a silver dollar on humeral attachment. The teres major attaches to the posterior scapula, then straight across to the anterior (front) of the shoulder, attaching to the front of the humerus. This muscle along with the latissimus dorsi, forms the back part of your armpit. This muscle refers pain into the lateral shoulder and sometimes into the lateral forearm. These two muscles are rarely inflamed, and are ignored by most therapists.

SUPRASPINATUS MUSCLE

ACTION: abducts the humerus (lifts the arm) REFERRAL: lateral shoulder and arm COMMENTS: This muscle runs under the clavicle, attaching to the top of the humerus. It pulls the arm out to the side. The supraspinatus and deltoid are the only two muscles that lift the arm to the side (the trapezius helps to stabilize and helps after 90 degrees). If strained, it can mimic subacromial bursitis. To work the muscle belly, you must work through the trapezius. This is one of the 4 rotator cuff muscles.