roo 



NERVOUS SYSTEM OF THE HORSE 



down the arm in front of the arter5^ Near its origin it is joined by a large branch 

 with the musculo-cutaneous nerve, thus forming a loop in which the artery appears 

 to be suspended. Near the elbow it crosses obliquely over the artery (posterior 

 radial) and lies behind it on the internal lateral ligament. Below the joint it 

 again crosses the artery and lies behind the radius and the lower part of the long 

 internal hitcral ligament. 



At the elbow the nerve is eovered by the posterior superfieial pectoral muscle and is crossed 

 by the larfje ol)lique connection between the cephalic and l)raclnal veins. The variable and often 

 piexiforni venous arrangement renders approach to the nerve here undesirable. It can be reached 



Internal mvtncnrpal vein 



Mehicarpnl or vnUir nerve 



DUjiUil artery 



Dorsal or anterior digital branch — 

 Volar or posterior digital branch 



Distal end of external snudl nieta- 

 earpal bone 



Large metacarp(d bone 

 Suspensory ligament 



Superficial flexor tendon 



Posterior annular ligament of 

 fetlock 



Extensor branch of suspensory 



ligament 



Oblique or middle inferior 



sesamoidean lig. 



Volar lig. of pastern joint 



Proximal annular lig. of digit 



Deep flexor tendon 



Distal annular lig. of digit 



■imj^ 



Fk;. .522. — DissicrTiox of Oist.m, P.\kt of Richt ]"ori: I.imh of Horse, Viewf.d from Behind. 

 /, I-aleral cartilage; 2, S, 4, ligainent.s from first phalanx to third sesamoid, hiilb of heel, and lateral cartilage. 



(.\fter Schmaltz, .\flas d. .\nat. d. Pferdeis.) 



best by an incision jiisl Ix'iiind llic lower i)art of the long internal lateral ligament; here the nerve 

 lies under tlie decj) fascia in tlie fiUTOw between the radius and the anterior border of th(> flexor 

 carpi intertills, overlaiiped by the latter. In .some ctises tiie nerve retains its position in front of 

 the artery at the e!l)ow, and in others it crosses tlie deep face of the artery. 



Passing beneath the inlcrjial fh^xor of the carpus, tlie nerve continues downward 

 in the forearm with the jxjsterior radial vessels, and (Uvides at a variable distance 

 above the cariMis into two i)ranches; these are the internal volar or metacarpal 

 nerve and the brancli whicii unites with the ulnar to form the corresponding 

 external nerve. 



At the proximal part of the forearm the nerve runs almost straight downward along the 

 posterior border of the long intermd lateral ligament, while the artery here inclines somewhat 

 backward. Thus the nerve is superficial to the artery for a short distance, then lies in front of 

 the latter to about the middle of the region, where it inchnes a little backward and arrives at the 



