What Is the Triceps Brachii?
The triceps brachii is a three-headed muscle that runs the length of the posterior upper arm. Chiefly employed in extension of the elbow joint, the long head of the muscle attaches to the scapula, and participates in moving the arm backward and toward the body, as in the pulling motion of raking leaves. As a relatively large muscle of the arm, the triceps is capable of moving a significant amount of weight, and has potential for injury when overworked. All three heads of the triceps brachii share a common tendon, which inserts at the olecranon of the ulna, but each have a distinct origin near the shoulder joint. The lateral head, furthest from the torso, originates at the infraglenoid tubercle of the shoulder blade. This section of the muscle assists in shoulder motions in addition to elbow joint movements. The medial head and lateral heads originate at separate areas of the posterior surface of the humerus, making these heads primarily responsible for elbow extension. The triceps is e
