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.

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