The olecranon is an anatomical feature of the posterior-proximal ulna. It forms the most pointed portion of the elbow. The three distal heads of the triceps brachii muscle, which help to increase the lever arm, converge to form a single tendon inserted in the olecranon. The three proximal heads are attached to the scapula and the outside and inside posterior surfaces of the humerus. The triceps brachii makes up the bulk of the back of the upper arm and is responsible for extension of the shoulder and elbow joint.
