58 LABORATORY MANUAL OF HUMAN ANATOMY 



Greater Pectoral Muscle (M. pectoralis major). 



Make the muscle tense by abducting the upper extremity. 

 Remove the fascia pectoralis from its surface and the deltoid 

 portion of the fascia brachii from the anterior margin of the 

 M. deltoideus. Stop at the plica axillaris anterior before reach- 

 ing the fascia axillaris. Avoid injury to the vena cephalica and 

 the acromial ramus of the arteria thoraco-acromialis (0. T. 

 humeral thoracic artery). 



FIG. 11. 





Insertion of 

 pectoralis 



Intermediate 

 entopectoral 



slip 



Pectoralis 

 minor 



M. pectoralis major with deficiency of sternocostal portion, and resulting production of an atypical 

 displaced intermediate pectoral muscle (M. tensor semivaginae articulationis humero-scapularis, Gruber, 

 M. pectoralis minimus). Adult human subject. From a fresh dissection. (After G. S. Huntington, 

 Amer. Jour, of Anat., Baltimore, 1903, vol. ii., No. 2, Plate I., Fig. 1. ) 



Note in connection with the M. pectoralis major 



(a) Its form. 

 (&) Its position. 



