138 



DISSECTION OF THE DOG 



?i. medianus 



n, ulnaris 



Ramus superftcialis 

 Ramus frofundus 



nn. metacarpei 

 volares I, II, et III 



n. digitalis volaris 

 lateralis digiti V 



n. metacarpeus 

 volaris I V 



nn. digitales 



^volares communes 



II, III, etir 



Fia. 52. — Diagram of nerves on the volar aspect of the manus. 



the flexor tendjDns and 

 divides into two parts, of 

 which one supphes the fifth 

 digit, and the other follows 

 the groove between the 

 fourth and fifth metacarpal 

 bones to join a part of the 

 ramus profundus. 



A. MEDiANA. — The bra- 

 chial artery proceeds from 

 the arm into the forearm by 

 following the median nerve 

 under the pronator teres, 

 and so becomes the median 

 artery. About the junction 

 of the proximal and middle 

 thirds of the forearm the 

 median terminates by divid- 

 ing into two vessels of 

 unequal size — the radial and 

 ulnar arteries. 



The collateral branches of 

 the median artery are (1) 

 articular to the elbow- joint ; 

 (2) muscular to the flexors ; 

 and (3) the common inter- 

 osseous artery (a. interossea 

 communis). 



The common interosseous 

 artery leaves the median a 

 short distance distal to the 

 elbow-joint and soon divides 

 into a dorsal and a volar 

 branch. The dorsal inter- 

 osseous artery (a. interossea 

 dorsalis) at once pierces the 

 interosseous membrane be- 

 tween the radius and the 

 ulna, and thus gains the 

 dorsal aspect of the forearm. 

 Here it is continued distal- 

 wards between the extensor 

 carpi ulnaris and the exten- 



