Rotator cuff

The rotator cuff is an anatomical term given to the group of muscles and their tendons that act to stabilise the shoulder.

These muscles all connect to the head of the humerus forming a cuff at shoulder joint. They are important because they hold the head of the humerus in the small and shallow glenoid fossa of the scapula. The rotator cuff is continuous with the joint capsule of the shoulder.

The four muscles that compose this group are:

• Supraspinatus which comes from the supraspinous fossa of the scapula. This abducts the arm.
• Infraspinatus which comes from the infraspinous fossa of the scapula. This laterally rotates the arm.
• Teres minor comes from the lateral border of the scapula, and also laterally rotates the arm.
• Subscapularis originating from the subscapula fossa of the scapula. This muscle medially rotates the humerus.

This group of tendons can become torn, leading to pain and restricted movement of the arm.