Anatomy study note · Upper limb

Pectoralis major

The large fan-shaped muscle of the front of the chest, forming the anterior wall of the axilla.

Key points

• Clavicle + sternum + upper 6 costal cartilages → lateral lip of the bicipital groove.
• Medial + lateral pectoral nerves (C5–T1).
• Adducts + medially rotates; clavicular part flexes.
• Forms the anterior axillary fold.
• Limb muscles: in situ from limb-bud mesenchyme.
• Upper limb bud C4–T2; lower limb bud L2–S2.
• Skeletal muscle: multinucleated, peripheral nuclei, striated.
• Epimysium → perimysium → endomysium.

The full note in the atlas also covers

Origin · Insertion · Action · Nerve supply · Histology · Development · Clinical notes

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Written from

• Snell’s Clinical Anatomy by Regions, 10th ed., ch. 3, PDF pp. 260–264, 301
• Inderbir Singh’s Human Embryology, ch. 7, PDF p. 109; ch. 10, PDF pp. 142–145
• BRS Cell Biology & Histology, 7th ed., ch. 8, PDF pp. 135–144

More from the upper limb

• Pectoralis minor
• Phalanges of the hand
• Pronator quadratus
• Pronator teres
• Radial artery
• Radial nerve
• Radioulnar joints and interosseous membrane
• Radius
• Rhomboid major
• Rhomboid minor
• Scapula
• Serratus anterior

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