16 JOURNAL OF THE 



tinct muscles. These may be arranged in two groups* 

 One group includes the first, second, and third ^^6^/0- 

 rals, all of which muscles arise from the anterior por- 

 tion of the sternum and run outwards. This group 

 corresponds in a general way with the more superficial 

 {P. major) of the two pectorals of man. The other 

 group includes the fourth and fifth pectorals, which 

 muscles in general pursue a course from the sternum 

 outwards and anteriorly to the proximal end of the hu- 

 merus. This group corresponds with the inner human 

 pectoral {P. minor). In a general way it may be said 

 that the muscles of one group cross those of the other. 

 (On this crossing of the pectoral muscles, see Wilder 

 and Gage, p. 235). 



The first pectoral \^ the most superficial of the group. 

 It is rather narrow and band-shaped, and arises from 

 the presternum and the raphe in front of the latter. 

 The raphe in question is the median connective tissue 

 septum between the posterior portions of the sterno- 

 mastoids, and between the anterior portions of the sec- 

 ond pectorals. The greater part of the muscle arises 

 from the mid-ventral line of the presternum, along the 

 anterior three fourths of that bone. Only the extreme 

 anterior part arises from the raphe. 



Part of the muscle is inserted along with a shoulder 

 muscle, the cephalo-humeral. Part is inserted into 

 the fascia of the fore-arm, along with a slip from the 

 third pectoral. 



Synonymy. Pecto-antehrachial, S.-D., vol. II, p. 

 352 (the slip from the third pectoral is regarded as the 

 "second chef" of the pectoa7itel)rachial) 'pecto-a?ite- 

 brachial, W. & G., p. 236 (above-mentioned slip is 

 counted as the "caudal division of the pecto-antebra- 



