Pectoralis minor is the key muscle producing anterior scapular tilt (inferior angle lifted away from the thorax), which reduces the subacromial space and contributes to impingement. Its tightness is extremely common in office workers with rounded shoulder posture. It also passes anterior to the brachial plexus and axillary vessels, forming the medial wall of the axilla — its hypertrophy can compress these structures (pectoralis minor syndrome).
| Origin | Outer surfaces of ribs 3-5 near their costal cartilages |
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| Insertion | Medial border and upper surface of the coracoid process |
| Nerve Supply | Medial pectoral nerve (C8, T1) with C6-C7 contributions from the lateral pectoral nerve |
| Blood Supply | Pectoral branch of the thoracoacromial artery |
| Actions | Depresses and protracts the shoulder girdle; Tilts the scapula anteriorly (internal rotation of the inferior angle toward the thorax); Accessory inspiratory muscle — elevates ribs 3-5 when the scapula is fixed |
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Pectoralis minor tightness is assessed by the pectoralis minor index (distance from the coracoid to the fourth rib sternal attachment normalised to height) on clinical assessment. Stretching in the corner stretch position (arms abducted, forearms on the doorframe) is the primary treatment. Pectoralis minor syndrome — neurovascular compression in the costocoraco-id space — may require surgical release in refractory cases.
Pectoralis minor is palpable deep to the pectoralis major between the chest wall and the coracoid, becoming firm during resisted shoulder depression or accessory breathing.
Anterior scapular tilt and subacromial space reduction from tight pectoralis minor managed with stretching and scapular control rehabilitation.
