Pectoralis minor
Pectoralis minor
Pronunciation: pek-tor-AL-iss MY-nor
For beginners
A small muscle hidden under the big chest muscle. Instead of moving the arm, it tilts and pulls the shoulder blade forward and down.
Show the advanced explanation
A tight pectoralis minor can anteriorly tilt the scapula and contribute to rounded-shoulder posture and impingement-type symptoms, which is why chest-opening mobility is often programmed.
Structure & function
- Location
- A small muscle beneath the pectoralis major, running from the upper ribs to the shoulder blade.
- Origin
- Ribs 3–5.
- Insertion
- Coracoid process of the scapula.
- Main action(s)
- Draws the scapula forward and down (protraction and depression); helps with forced inhalation by raising the ribs when the scapula is fixed.
- Joint(s) crossed
- Scapulothoracic articulation
- Movement plane
- multiple
- Innervation
- Medial pectoral nerve (C8–T1)
- In daily movement
- Helps position the shoulder blade for reaching forward and down.
- In exercise
- Stabilizer of the scapula during pressing and dips.
- Commonly confused with
- Confused with the pectoralis major — the major moves the arm, the minor moves the scapula.
- Common misconceptions
- It is not a big 'mass' muscle; its importance is postural and stabilizing.
⚠ Safety note
Chronic tightness may relate to rounded-shoulder posture; persistent shoulder symptoms should be professionally assessed.
Sources
“The pectoralis minor moves the scapula (protraction/depression) and assists respiration.”
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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