The long head of the triceps brachii muscle is a muscle of the back of the arm, originating from the scapula and shoulder to insert at the elbow. The triceps brachii has three heads (connective immovable muscle) and is the only muscle on the back of the upper arm. It connects the humerus (upper arm bone) and the scapula (shoulder blade) to the ulna (longest of the forearm bones) and is the primarymycontentbreak extensor of the elbow. The three heads are the lateral, the medial, and the long head. The long head of the triceps brachii muscle, apart from the other triceps muscles, has a role in stabilizing the shoulder joint.