ArmsSource-checked

Coracobrachialis

Pronunciation: kor-uh-koh-bray-kee-AL-iss

For beginners

Despite living in the 'arm' region by location, this small muscle actually only works the shoulder, not the elbow — it helps lift and bring the arm across the body.

Show the advanced explanation

Its name reflects both its origin (coracoid process) and its neighbor tissue (brachii/arm), but functionally it belongs with the shoulder flexors rather than the elbow flexors/extensors.

Structure & function

Location: A small muscle on the inner, upper part of the arm, near the armpit.
Origin: Coracoid process of the scapula.
Insertion: Middle of the humerus shaft.
Main action(s): Flexes and adducts the arm at the shoulder; it does not act on the elbow at all.
Joint(s) crossed: Shoulder joint only
Movement plane: sagittal (flexion); frontal (adduction)
Innervation: Musculocutaneous nerve (C5–C7)
In daily movement: Assists in bringing the arm forward and across the body, such as reaching across your body.
In exercise: A synergist rather than a prime mover in most exercises; assists shoulder flexion in movements like front raises and light pressing.
Commonly confused with: Its location often leads people to assume it helps bend the elbow, but it has no elbow-joint action at all.
Common misconceptions: There is no dedicated 'coracobrachialis exercise' — it is trained incidentally through shoulder-flexion movements.

⚠ Safety note

Rarely a source of isolated injury; general shoulder and arm-strain precautions apply.

Sources

“The coracobrachialis flexes and adducts the arm at the shoulder joint and does not cross the elbow.”

Anatomy and Physiology 2e — OpenStax, Rice University · Ch. 11.5 Muscles of the Pectoral Girdle and Upper Limbs

Peer-reviewed textbook · License: CC BY-NC-SA 4.0 · Last checked 2026-07-19

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