Pectoralis major
Musculus pectoralis major
MuscularSuperficial musclesThoraxLeft and right
View left in 3D View right in 3D
- What it is
- Large fan-shaped chest muscle arising from the medial half of the clavicle, the front of the sternum and the upper six costal cartilages; its fibres converge on a folded flat tendon inserting on the lateral lip of the intertubercular groove (crest of the greater tubercle) of the humerus.
- Function
- Adducts and medially rotates the arm; the clavicular head flexes it, the sternocostal head pulls the raised arm down and forwards.
- Size
- About 20 cm across, 1–1.5 cm thick; insertion tendon ~5 cm wide.
- Clinical note
- Congenital absence of its sternocostal head is Poland syndrome; the muscle is often used as a pedicled flap in head-and-neck reconstruction.