M. SEIZRATUS MAGNUS. 247 



Dermo-humeralis ( 629) A part of this is seen to pass to the ectal aspect of the M, 

 latissimus. 



Entopectcralis, dc. caudalis ( 656). As hi Fig. 72, which was taken from the same 

 preparation, this division presents a well-marked subdivision. 



Entopectoralis, dv. cephalica ( 658). Thicker than the caudal division, this is inserted 

 chiefly upon the trockiter, but here, as in some other cases, a slender tendon (Tn. x.) passes 

 to the coraeoid process. 



Lntissimus (^ 635). The ectal aspect was presented in Fig. 66 and 67; hero are seen 

 the ental surface and its connections with the arcus bicipitalis and the M. teres. 



Levrttor anguli scapulce ( 666). The general appearance of the muscle is fairly indi- 

 cated, but the removal of the other soft parts from the line of origin has given the proxi- 

 mal end the look of having been cut off. The proximo-cephalic angle also extends some- 

 what too far cephalad. The interval between it and the serratus magnits was artificially 

 produced. The two muscles are evidently parts of the same general muscular lamina, but 

 there are sufficient practical reasons for treating of them separately. 



Sterno-mastoidens ( 622). This is better shown in Fig. 72. 



Subscn pillar is ( 670). Especially noteworthy are the appearances of its continuity 

 with the adjacent muscles, serratus magnns, lecator anguli scapulae, teres and supraspina- 

 tus. Its tendon of insertion is crossed by the coracoideus. 



Supraspinatus ( 675). Between this and tlis humeral part of the subscapularis is the 

 triangular interval mentioned in the dissection of the coracoideus ( 668). 



Teres ( 680). As in the other figures, the word major has been inadvertently added. 



Xiphi-humeralis ( 660). The humeral end is reflected like the two divisions of the 

 entopeetoralis. 



Occipito-scapularis ( 617). Its ventral margin is seen to thicken caudad. 



M. SERRATUS MAGNUS. 



664. Synonymy. The human serratus magnus, G., A, 402, Q., A, 1, 196 ; "grand 

 dentele" [thoracic portion], S.-D., A, II, 835 ; grand dentele, Ch., A, 250 ; great serratus, 

 Ch. (Fl.), A, 236 ; serratus magnus, Miv., B, 145. 



Figures. Ectal aspect (73) ; scapular end (75) ; insertion area (43). 



Posture. Latericumfoent ; the venter toward the dissector ; a 

 block transversely under the thorax just caudad of the elbows. 



Exposure. For the complete exposure of this muscle it is neces- 

 sary to reflect all the muscles thus far enumerated, excepting the 

 sterno-mastoideus ; also to remove the larger part of the thoracic 

 portion of the M. ectobliquus " external oblique muscle of the 

 abdomen" (Fig. 73), and to remove or partly displace the thoracic 

 portion of the M. rectus and some other muscles upon the cephalic 

 region of the thorax. 



Lift the elbow so that the brachium rests at a right angle with 

 the side of the neck. Dissect out the fat and connective tissue thus 

 exposed between the shoulder and scapula and the thorax, then 

 divide and reflect the axillary vessels and nerves. This will permit 

 the whole arm, with the scapula, to be turned dorsad so as to expose 



