N. CIRCUMFLEXUS. 385 



584 ; Gray, A, 673). There are two of these nerves, or, if the nerve 

 of the latissimus be counted, three (Fig. 105, 106). They all arise 

 from the dorsal side of the "brachial plexus, as shown in Fig. 104 and 

 106. The most cephalic one goes to the M. subscapularis, and the 

 intermediate one mostly to the teres. The long subscapular or 

 nerve of the latissimus passes caudo-laterad to the M. latissimus 

 in connection with a branch of the subscapular artery ( 942). 



Dissection. The position of the nerves is indicated on the fig- 

 ures referred to. They may be isolated with the tracer ; this should 

 be done very carefully on account of their position with reference 

 to the other nerves. 



1024. N. circumflexus (Fig. 104, 105, 106 ; Quain, A, I, 584 ; 

 Gray, A, 673). The circumflex nerve arises from a sort of interme- 

 diate branch joining the 6th, 7th and 8th cervical nerves. For a 

 short distance it is in the closest relation with the cephalic of the 

 subscapular nerves. It passes nearly laterad and follows the cir- 

 cumflex artery as it winds around the dorsal side of the proximal 

 end of the humerus to terminate finally in the M. clavo-deltoideus ; 

 see 941. 



Dissection. Commence at the point where the nerve is crossed 

 by the musculo-cutaneous, and trace it first to its origin, and then 

 to the point where it disappears in company with the circumflex 

 artery. The termination may then be seen by lifting the cephalic 

 edge of the clavo-deltoideus just distad of the trochiter. Its entire 

 course may be traced from the periphery by cutting away the 

 muscles. 



1025. N. medius s. medianus (Fig. 104, 105, 106 ; Quain, A, I, 

 590 ; Gray, A, 675). The median nerve in the cat is formed by three 

 branches, shown in Fig. 106, the 'brachial artery passing between 

 the cephalic and intermediate. It follows the direction of the artery, 

 lying ectad of it in most of its course and traversing with it the Fm. 

 epitrochleare, where it receives an anastomosing branch from the N. 

 mmculo-cutaneus ( 1022). In the concavity of the elbow the nerve 

 passes entad of the M. pronator teres and follows the general course 

 of the bones of the antebrachium to the wrist. It furnishes branches 

 to the muscles on the ventral aspect of the antebrachium, and espe- 

 cially the N. interosseus anterior, which accompanies the artery of 

 the same name ( 944, D). Finally, it is distributed to the struc- 

 tures on the palmar aspect of the manus. 



Dissection. Commence at about the middle of the brachium 

 25 



