Coracobrachialis (Shoulder Region)

m. coracobrachialis (pars humeralis)

The coracobrachialis at the shoulder region represents its proximal portion at the coracoid attachment and in the anterior axilla, where the musculocutaneous nerve pierces the muscle. It is the smallest of the three muscles arising from the coracoid and the only one the musculocutaneous nerve penetrates.

Nerve: Musculocutaneous nerve (C5, C6, C7) Blood Supply: Brachial artery branches Region: Shoulder

Anatomical Data

Origin, Insertion & Supply

Origin	Coracoid process apex — conjoined with short head biceps
Insertion	Middle third of the medial humeral shaft
Nerve Supply	Musculocutaneous nerve (C5, C6, C7)
Blood Supply	Brachial artery branches

Biomechanics

Function & Actions

Actions	Flexes the shoulder; Adducts the shoulder; Assists in medial rotation of the humerus

Clinical Relevance

Clinical Notes

The musculocutaneous nerve pierces the coracobrachialis 5-8 cm distal to the coracoid, making the muscle a landmark for nerve preservation in shoulder surgery. Coracobrachialis contracture (rare) contributes to shoulder adduction deformity. In the Latarjet procedure, the conjoined coracoid graft includes both the coracobrachialis and short head biceps attachments, providing the dynamic sling effect.

Palpation

Palpable in the medial upper arm during resisted shoulder flexion-adduction.

Pathology

Common Injuries & Conditions

Musculocutaneous Nerve Injury in Coracobrachialis

Musculocutaneous nerve damage at its coracobrachialis penetration point during shoulder surgery producing weakness of elbow flexion (biceps and brachialis) and lateral forearm numbness.