Shoulder: Supraspinatus, Infraspinatus, Teres Minor, Subscapularis

Rotator Cuff Muscle Pain, Injury, and Function

(1)

(2)

(3)

(4)

Rotator Cuff: Supraspinatus, Infraspinatus, Teres Minor & Subscapularis

In order as pictured above, the (1) Supraspinatus, (2) Infraspinatus, (3) Teres Minor, and (4) Subscapularis--known as the rotator cuff muscles--are a group of muscles which work together to provide the shoulder joint with dynamic stability, helping to control the joint during rotation. Please note the "job" of each muscle below:

• Supraspinatus-the Supraspinatus muscle is one of the four muscles which make up the rotator cuff. Its main function is to stabilize the upper arm by holding the head of the humerus in position. Its actions are abduction (movement away from the body) and, again, humerus stabilization.
• Infraspinatus-the Infraspinatus muscle is the main external rotator (rotation away from the body) of the shoulder joint. Its actions are external rotation and shoulder abduction.
• Teres Minor-its main action, along with Infraspinatus is to externally rotate the shoulder joint. Its actions are external rotation and shoulder abduction.There are two Teres muscles, the other being Teres Major which is not included in the rotator cuff.
• Subscapularis-this muscle also acts to hold the head of the humerus in position and prevents it moving forwards. Its actions are internal rotation (rotation towards the body) and adduction (movement towards the body).

Shoulder Injury: Understanding Rotator Cuff Muscle Actions

Now that you have a basic understanding of the actions and locations of each rotator cuff muscle, you may now be in a better position to describe and relay any syptoms you are experiencing, related to injury, to your physician.