Coracobrachialis
Musculus coracobrachialis
A slender muscle from the coracoid process to the middle of the medial humerus. It flexes and adducts the arm and is pierced by the musculocutaneous nerve.
Overview
Coracobrachialis arises from the tip of the coracoid process together with the short head of biceps. It inserts on the middle third of the medial surface of the humerus. It is the smallest muscle of the anterior compartment of the arm and acts only at the shoulder. It flexes and adducts the arm and helps resist downward dislocation of the humeral head when a weight is carried. It is a useful landmark, because the musculocutaneous nerve pierces it about 5–8 cm below the coracoid. The median and ulnar nerves and the brachial artery run along its medial border in the upper arm.
Anatomy
- Origin
Tip of the coracoid process of the scapula.
- Insertion
Middle third of the medial surface of the humerus.
- Action
Flexion and adduction of the arm.
- Innervation
Musculocutaneous nerve (lateral cord), which pierces it.
- Nerve roots
C5–C7
- Arterial supply
Muscular branches of the brachial artery (and the anterior circumflex humeral artery).
- Relations
Pierced by the musculocutaneous nerve. The brachial artery and the median nerve lie along its medial border.
Function
- Flexes and adducts the arm at the shoulder
- Stabilises the humeral head
Compiled from standard anatomy and physiology references — see the Muscular System sources. For education only; not medical advice.