A large fleshy muscle in the posterior compartment of the upper arm. It has three heads: the long head originates from the infraglenoid tubercle on the scapula (shoulder blade), the lateral head originates from the upper half of the posterior humerus, and the medial head originates from the lower two-thirds of the posterior humerus. The triceps has a common tendon of insertion on the olecranon process of the ulna. The long head stabilizes the scapula, and assists with extension and adduction of the upper arm about the shoulder. The primary action of the medial and lateral heads is extension of the forearm around the elbow.
Subjects: Sports and Exercise Medicine.