Name
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.