18 JOURNAIv OF THK 



raphe is thus overlooked. Gorham & Tower agree 

 with Mivart. 



The third pectoral is a wide muscle. Anteriorly it 

 is covered by the /^r^/ and second pectorals, but the pos- 

 terior half or more is superficial. It arises from the 

 above-mentioned raphe, from the presternum, and from 

 the next two sternebrae, its orig-in thus extending- as 

 far back as the attachment of the fourth costal cartilage 

 to the sternum. Onh^ the extreme anterior portion of 

 the muscle arises from the raphe. Behind these fibres, 

 the muscle arises from the ventro-lateral surface of the 

 presternum, along the whole length of the latter. The 

 portion of the muscle arising from the next two divis- 

 ions (sternebrae) of the sternum is superficial. 



The chief insertion is on the humerus, and is a very 

 long one. The proximal part of this insertion is by a 

 thin aponeurosis to the extreme outer surface of the 

 humerus. The middle part is directly by muscle fibres 

 to the ventral surface of the humerus. The distal 

 part is again by aponeurosis to the ventral surface of 

 the humerus. 



The most anterior fibres of the muscle are inserted 

 into a small tendon which quickly divides. One divis- 

 ion passes externally to the shoulder joint, and is at- 

 tached to the outer end of the clavicle. The other di- 

 vision passes internally to the shoulder-joint, and ter- 

 minates in the fascia on the mesal surface of the scap- 

 ula in the interval between the supra-spinatus and the 

 sub-scapularis. 



The muscle is also inserted into the bicipital arch. 

 As has already been mentioned, a slip lying along the 

 posterior border of this muscle separates from it, and 

 is inserted along with t\i^ first pectoral. 



Synonomy. Second chef du larg-e pectoral, S.-D., 



