Pectoralis Minor – Anatomy Breakdown, Muscle by Muscle

Here We Go!

Treadwell, DPT back with another Anatomy Breakdown – Muscle by Muscle.
Today we’re taking a look at the Pectoralis Minor, the smaller and deeper counterpart to the pec major. While it’s not the show muscle everyone trains in the gym, the pec minor plays a big role in scapular movement and shoulder mechanics. It’s one of those muscles that doesn’t get much credit, but dysfunction here can cause a whole lot of problems.

Origin & Insertion

The Pectoralis Minor originates from the anterior surfaces of the 3rd to 5th ribs near their costal cartilages.
It inserts onto the medial border and superior surface of the coracoid process of the scapula.

Function

The pec minor’s main job is scapular stabilization. It draws the scapula forward and downward, playing a role in protraction and depression. It also assists in raising the ribs during forced inspiration when the scapula is fixed.

Innervation

Innervation comes from the medial pectoral nerve (C8–T1).

Clinical & Research Insights

• Posture problems: A tight pec minor can contribute to rounded shoulders and forward head posture.

• Thoracic outlet syndrome: Due to its anatomical location, this muscle can be involved in compression syndromes affecting nerves and vessels passing into the upper limb.

• Rehab relevance: Stretching, release, and retraining are common strategies for addressing pec minor–related dysfunction in both clinical and athletic populations.