Coracobrachialis Muscle

What is the Coracobrachialis

The coracobrachialis is a muscle near the shoulder, in the upper arm’s anterior compartment. The long, slender muscle plays a vital role in flexing and adducting the upper arm.

Location

Origin	The scapula’s coracoid process
Insertion	Medial surface of the upper arm bone humerus, along the middle of the body of the humerus (the brachial region)

The name ‘coracobrachialis’ refers to its origin and insertion points, with ‘coraco’ referring to the coracoid process and ‘brachialis’ to the brachial region.

It is located near the short head of the biceps brachii, behind the pectoralis major – two other muscles attached to the coracoid process. Located behind the coracobrachialis are the medial head of triceps and the tendons of the latissimus dorsi, subscapularis, and teres major.

The coracobrachialis contributes to the formation of the lateral border of the axilla — the region between the top of the upper limb and the thorax. The muscle can be easily felt in this region from the outside.

Functions

Action

Flexing and adducting the shoulder (glenohumeral) joint

Its primary function is helping in bending the upper arm (flexion) at the shoulder joint and pulling the arm toward the torso (adduction) from an outstretched position.

In these positions, the coracobrachialis acts as the main antagonist to the deltoid muscle’s action and keeps the head of the humerus stable in its socket. 

It also helps with the internal rotation of the shoulder.

Innervation

Nerve

The musculocutaneous nerve, which has its roots in the spinal nerves C5, C6, and C7

Blood Supply

Artery

The muscular branches of the brachial artery