rotator cuff n.
A set of muscles and tendons that secures the arm to the shoulder joint and permits rotation of the arm. Also called musculotendinous cuff.
A group of muscles and tendons attaching the shoulder to the scapula (shoulder blade) that provide stability to the shoulder joint and act to rotate the arm. Injuries to the rotator cuff often happen when the arm is repeatedly moved over the head with great force, as when pitching a baseball.