Coracobrachialis muscle

The coracobrachialis is the smallest of the three muscles found in the anterior compartment of the arm.

Origin

It typically arises from the apex of the coracoid process of the scapula, a point often shared with the short head of the biceps brachii. Some muscle fibers may also originate from the intermuscular septum separating these two muscles.

Insertion

The muscle inserts onto the medial surface of the shaft (body) of the humerus, just above the bone's midpoint.

Innervation

The musculocutaneous nerve perforates the coracobrachialis, providing its innervation. This nerve then continues distally to supply the biceps brachii and brachialis muscles.

Action

The coracobrachialis acts to flex and adduct the arm at the glenohumeral (shoulder) joint. It also plays a role in stabilizing the humeral head within the joint during these movements.