222 MAMMALIA. 



after its egress from between the ribs ; it pierces the broadest muscle of the 

 back, and divides into branches to be distributed on the skin at the inner and 

 posterior part of the arm. 



8. Musculo-cutaneous nerve ; it arises from the sixth cervical along with the 



outer portion of the median ; it gives a branch to the pectoral muscle and the 

 coraco-brachial, and then passes off to terminate on the biceps. 



9. Median nerve ; the sixth cervical having given off the nerve analogous to the 



usual musculo-cutaneous, the remaining part gives off a branch, which sends 

 one back to the internal brachial muscle behind the tendon of the biceps, and 

 then gives branches to the skin of the fore-arm, in the place of the cutaneous 

 portion of the musculo-cutaneous in man ; it then joins the branch from the 

 seventh cervical and first dorsal nerves, about an inch above the elbow, to 

 form the median nerve, which is small as compared with that in man ; the 

 nerve thus formed passes under the origin of the round pronator muscle, and 

 gives branches to this, the radial flexor muscle of the wrist, and the sublime 

 and deep flexors of the fingers ; it then passes by the side of the radial flexor 

 and between the sublime and deep flexors underneath the annular ligament ; 

 it is continued in the hand between the tendons of these muscles, at the 

 division of which it sends off branches ; it gives filaments to the skin of the 

 palm, and a branch to the short prominence corresponding with the thumb, 

 and the inner side of the first finger, and a branch to be joined by one from 

 the deep palmar for the outer side of the first finger and the inner side of the 

 second ; another branch also to be joined by a branch from the deep palmar 

 for the outer side of the second and the inner side of the third. 



10. Ulnar nerve ; it is formed from the seventh cervical and first dorsal, as well as 

 the inner portion of the median ; it descends behind the inner condyle of the 

 humerus, covered by thick fascia and by part of the sublime flexor muscle ; 

 it then passes down the fore-arm between the flexors of the fingers and the 

 ulnar flexor of the wrist ; in the fore-arm it is much larger than the 

 continuation of the median ; it sends a branch to the ulnar side of the 

 sublime and deep flexors, and the ulnar flexor ; near the hand it sends a 

 branch to the back of this part, to communicate with the radial branch of the 



