innervated by has muscle origin has muscle insertion sternum humerus pectoralis minor clavicle bone muscle of shoulder pectoral muscle pectoralis major The pectoralis major is a thick, fan-shaped muscle, situated at the upper front of the chest wall. It makes up the bulk of the chest muscles in the male and lies under the breast in the female. Underneath the pectoralis major is the pectoralis minor, a thin, triangular muscle. [WP,unvetted]. EMAPA:18179 VHOG:0000895 FMA:9627 EHDAA:8311 EHDAA2:0001424 UBERON:0002381 SCTID:181624003 Wikipedia:Pectoralis_major_muscle pectoralis major muscle MA:0002354 pectoralis major muscle structure NCIT:C33284 musculus pectoralis major thoracic nerve