Overview

The pectoralis minor is a small triangular muscle beneath pectoralis major. It connects the ribs to the coracoid process of the shoulder blade and helps position the scapula during reaching and breathing.

Location

Lies deep to pectoralis major
Runs from ribs 3–5 toward the front of the shoulder
Attaches to the coracoid process of the scapula

Origin, Insertion, Nerve Supply, and Action

Origin: Anterior surfaces of ribs 3–5
Insertion: Medial and upper surface of the coracoid process
Nerve supply: Mainly medial pectoral nerve, C8–T1
Action: Draws the scapula forward and downward; assists downward rotation and forced inspiration

Function

Helps stabilise the scapula against the chest wall
Assists reaching and pushing
Contributes to scapular tilt
Can help elevate the ribs during laboured breathing

Structures It Connects To

Movements It Assists

Scapular protraction
Downward rotation
Shoulder-blade depression

Common Injuries

Strain or local irritation
Load-related sensitivity with repeated pressing
Contribution to altered scapular position when shortened or guarded

Pain Referral Patterns

Discomfort may be felt in the upper chest or front of the shoulder. Symptoms in this area can also come from the biceps tendon, rotator cuff, ribs, neck or other chest structures.

Clinical Relevance

Pectoralis-minor length is sometimes assessed when scapular posture or overhead motion is limited. A single “tight” muscle rarely explains a complete shoulder problem, and aggressive stretching is not appropriate for everyone.

Interesting Facts

The muscle attaches to the coracoid beside the short head of biceps and coracobrachialis.
Nerves and blood vessels to the arm pass nearby, making this region clinically important.

References

StatPearls. "Anatomy, Thorax, Pectoralis Minor." https://www.ncbi.nlm.nih.gov/books/NBK556114/
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.

Pectoralis Minor