Pectoralis Minor Beneath the Skin

Description

Beneath the superficial pectoralis major, the left pectoralis minor appears as a thin, triangular sheet arising from the anterior surfaces of ribs 3 to 5 near their costal cartilages and running superolaterally to the coracoid process of the scapula. Its tendon inserts on the medial border and superior surface of the coracoid, lying anterior to the serratus anterior and deep to the clavipectoral fascia. Superiorly, the muscle sits inferior to the clavicle and medial to the deltoid, framing the anterior axillary region. Clinically, this is the muscle you want when teaching the anatomy of the axillary artery and brachial plexus as they pass deep to pectoralis minor, since its medial and lateral borders define classic infraclavicular exposure and help orient the pectoral (anterior) approach. Hypertrophy, spasm, or postural shortening can contribute to pectoralis minor syndrome, with neurovascular symptoms from compression in the retropectoralis minor space and scapular dyskinesis from persistent anterior tilt. A small muscle. A common source of confusion. Use this artwork for gross anatomy labs covering the anterior thoracic wall and axilla, for surgical anatomy figures in texts describing axillary dissection or infraclavicular blocks, and for rehabilitation materials addressing rounded-shoulder posture and anterior shoulder pain linked to coracoid tenderness. Anatomical accuracy verified by SciePro's Medical Advisory Board.