Coracobrachialis Insertion Tendon

insertio tendinis musculi coracobrachialis

The coracobrachialis inserts via a flat tendon on the anteromedial humerus at the mid-shaft level, approximately at the level of the deltoid insertion on the opposite lateral side. The musculocutaneous nerve (lateral cord of brachial plexus) pierces the coracobrachialis muscle belly 5-8 cm below the coracoid, making the muscle the key landmark for musculocutaneous nerve identification. The insertion is close to the medial intermuscular septum and the brachial artery.

Region: Upper Arm

Clinical Relevance

Clinical Notes

The coracobrachialis insertion is relevant as the landmark for the musculocutaneous nerve entry point, used during brachial plexus exploration and nerve transfer procedures targeting this nerve. Coracobrachialis traction spur — a bony excrescence at the mid-humeral medial cortex at the insertion — produces medial arm pain with arm abduction from traction stress at the tendon-bone junction, particularly in wheelchair users with chronic upper extremity loading. MRI and radiograph identify the spur at the coracobrachialis insertion level.

Pathology

Common Injuries & Conditions

Coracobrachialis Traction Spur in Wheelchair Users

Chronic traction loading of the coracobrachialis insertion from repetitive wheelchair propulsion produces a periosteal reaction and traction spur at the mid-humeral medial cortex, causing medial arm pain worsened by shoulder flexion and abduction; the spur is visible on AP humerus radiograph and resection through a medial arm approach provides pain relief.