56 ANTHROPOLOGY. 



tinct muscles. It serves important purposes in moving the arm and in 

 inspiration. 



Pectoralis minor, flat and triangular, arises from the external surface and 

 upper edge of the third, fourth, and fifth ribs, external to their cartilages, 

 and is inserted into the inner and upper surface of the coracoid process of 

 the scapula, near its anterior extremity, being here connected with the 

 coraco-brachialis and short head of the biceps. Use : to draw the shoulder 

 forwards, downwards, and upwards, also to assist the pectoralis major in 

 elevating the ribs in inspiration. 



Subclavius, small and round, arises by a flat tendon from the cartilage of 

 the first rib, external to the rhomboid or costo-clavicular ligament ; it is 

 inserted into the external half of the inferior surface of the clavicle. Its 

 use is to draw the clavicle and shoulder forwards and downwards ; also to 

 elevate the first rib in inspiration, if the shoulder and clavicle be raised and 

 fixed. 



/Se) ratus magnus, thin and broad, placed between the scapula and the ribs, 

 arises by eight or nine fleshy strips from the eight or nine superior ribs ; 

 the fibres ascending are inserted between the subscapular, rhomboid, and 

 levator anguli muscles into the base of the scapula, but particularly into the 

 superior and inferior angles. It depresses the scapula and draws it forwards, 

 raising the acromion process and the shoulder joint by rotating the scapula 

 on its axis ; it also plays an important part in inspiration. 



Intcrcostales are twenty-two in number on each side, eleven external and 

 eleven internal. The external commence at the transverse processes of the 

 dorsal vertebrae, arise from the inferior edge of each rib, and are inserted 

 into the external lip of the superior edge of the rib beneath. The internal 

 intercostals take an opposite direction and decussate the former ; they com- 

 mence at the sternum and are discontinued at the angles of the ribs. They 

 arise from the inner lip of the lower edge of each cartilage and rib, and 

 are inserted into the inner lip of the superior edge of the cartilage and rib 

 beneath. Both laminte co-operate to raise the ribs, the first rib being fixed 

 by the scaleni. 



Levatores costarum arise from the extremity of each dorsal transverse 

 process, and are inserted into the upper edge of the rib beneath, between 

 its tubercle and angle. They serve to elevate the ribs. 



Triangularis sterni, or sterno-costalis, arises from the posterior surface 

 and edge of the lower part of the sternum, and from the xiphoid cartilage, 

 and is inserted into the cartilages of the fourth, fifth, and sixth ribs. Use : 

 to depress and draw back the cartilages of the ribs, so as to assist in 

 expiration. 



PI. 121, fig. 9", pectoralis major; ", pectorahs minor; ', subclavius; \ ser- 

 ratus maguus; ^, intercostals. 



PI. 124:, fi^. 15", pectoralis major. Fig. 17', serratus magnus. 

 PI. 125, fig. 19^, subclavius; *, pectoralis minor; ", dentations of the 

 serratus magnus. 



PI. 126, fig. 20''''°, intercostals. 



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