Name

# Pectoralis Major

Pronunciation

(pek-to-RA-lis)

Origin/Proximal Attachment

Medial 1/3 of clavicle, anterior aspect of sternum, upper 6 costal cartilages, aponeurosis of external oblique

Insertion/Distal Attachment

Lateral lip of bicipital groove to the crest of the greater tubercle (clavicular fibres insert more distally, sternal fibres more proximally)

Action/Relevance

Adducts the armInternally rotates the armFlexes the arm (from an extended position) 4. Depresses the arm & shoulder

Innervation

Pectoral nerve - lateral (C5-7) to clavicular portion & medial (C8-T1) to sternal portion

Notes

On each side of the thorax, pectoralis major is an important muscular link to the upper arm. It is thick, triangular in shape and forms the anterior wall of the axilla. In the female, it is covered by the breast which is attached to the pectoral fascia.