The coracobrachialis is a long, thin muscle that acts exclusively on the shoulder joint. Its main functions are to draw the arm forward and to pull the arm toward the midline of the body. The muscle originates from the coracoid process, a small part of the scapula. It inserts midway along the inside of the humerus, a long bone in the upper arm. The muscle's insertion at the humerus lies between the attachments of two other arm muscles, the triceps and brachialis. Another key role of this muscle is to help stabilize the head of the humerus inside the shoulder joint. The muscle is innervated by the musculocutaneous nerve. It receives its blood supply from the muscular branches of the brachial artery. Overuse of this muscle during certain exercises, such as bench pressing, can lead to injury.