Pectoralis Minor
0% read · 1 min left
A thin triangular muscle deep to the pec major that pulls the scapula forward and down — the muscle most implicated in a rounded-shoulder posture when it's chronically tight.
Detail
Pectoralis minor sits underneath pectoralis major, running from ribs 3–5 up to the coracoid process of the scapula. Unlike pec major, it doesn't act on the shoulder joint at all — its job is entirely at the scapula, pulling it into protraction (forward) and downward rotation, and it assists forced inspiration by lifting the ribs when the scapula is fixed. It's chronically shortened by prolonged forward-shoulder posture (desk work, phone use), which is why it's a frequent target of stretching/mobility work rather than direct strength training — very few exercises isolate it, and most programs address it indirectly through pulling-volume balance and pec-stretch protocols.
Key facts
- Origin: ribs 3–5. Insertion: coracoid process of the scapula.
- Function: scapular protraction and downward rotation; assists forced inspiration.
- Acts only at the scapula, not the shoulder joint (unlike pectoralis major).
- Chronic tightness here is a common contributor to rounded-shoulder posture.
Connections
- pectoralis-major — the larger muscle it sits beneath; distinct origin, insertion, and joint action.
- scapular-movement — the category of motion (protraction/downward rotation) it produces.
Educational content only — not medical advice. Always consult a qualified professional for individualized guidance, especially around injury, pregnancy, or medical conditions.