Overview

The coracobrachialis is a slender muscle on the inner upper arm. It begins beside the short head of the biceps at the coracoid process and helps move the arm forward and inward.

Location

Starts at the front of the scapula
Runs along the inner upper arm
Lies deep to the short head of biceps

Origin, Insertion, Nerve Supply, and Action

Origin: Tip of the coracoid process, through a shared tendon with the short head of biceps
Insertion: Middle third of the medial humerus
Nerve supply: Musculocutaneous nerve, C5–C7
Action: Flexes and adducts the arm at the shoulder

Function

Assists forward elevation
Pulls the arm toward the body
Helps steady the humerus during carrying

Structures It Connects To

Movements It Assists

Shoulder flexion
Shoulder adduction
Bringing the arm toward the front of the body

Common Injuries

Muscle strain after forceful lifting or throwing
Local tenderness after repetitive upper-arm loading
Rare musculocutaneous nerve irritation near its passage through the muscle

Pain Referral Patterns

Pain may be felt at the front or inner side of the upper arm. Biceps, pectoral, shoulder-joint and nerve problems can create similar symptoms.

Clinical Relevance

The musculocutaneous nerve commonly pierces this muscle, making the relationship useful during neurological assessment and surgery around the front of the shoulder.

Interesting Facts

Its name describes both attachments: coracoid process to brachium, the upper arm.
It shares its upper tendon with the short head of biceps.

References

StatPearls. "Anatomy, Shoulder and Upper Limb, Coracobrachialis Muscle." https://www.ncbi.nlm.nih.gov/books/NBK545199/
OpenStax. "Muscles of the Pectoral Girdle and Upper Limbs." https://openstax.org/books/anatomy-and-physiology-2e/pages/11-5-muscles-of-the-pectoral-girdle-and-upper-limbs
Moore KL et al. Clinically Oriented Anatomy. Wolters Kluwer.

Coracobrachialis