700 



NERVOUS SYSTEM OF THE HORSE 



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

 with the nuisculo-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 lateral ligament. 



At the ell)o\v the nerve is covered by the posterior superficial pectoral muscle and is crossed 

 by the large olilique connection between the cephalic and brachial veins. The variable and often 

 plexiforni venous arrangement renders approach to the ner\'e here undesirable. It can be reached 



Internnl metncarpnl vein 



Metacarpal or volar nerve 



Digital artertj 



Dorsal or anterior digital branch 

 Volar or posterior digital branch 



Distal end of external small meta- 

 carpal bone 



Large metacarpal bone 

 Suspensory ligament 



Superficial flexor tendon 



Posterior annular liganierd 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 



Fig. 522. — Dissection of Di.stal F.\rt of Right Fore Limb oi. Horse, Viewed from Behind. 

 /, Lateral caitiLage; i2, S, 4, ligaments from first phalanx to third sesamoid, \ni\h of heel, and lateral cartilage. 



(After Schmaltz, Atlas d. Anat. d. Pferdes.) 



l)est by an incision just behind the lower part of the long internal lateral ligament; here the nerve 

 lies under the deep fascia in the furrow between the radius and the anterior border of the flexor 

 carpi internus, overlapped by the latter. In some cases the nerve retains its position in front of 

 the artery at the elbow, and in others it crosses the deep face of the artery. 



Passing beneath the internal flexor of the carpus, the nerve continues downward 

 in the forearm with the posterior radial vessels, and divides at a variable distance 

 above the carpus into two branches; these are the internal volar or metacarpal 

 nerve and the liranch which unites with tlu^ ulnar to form the corresponding 

 external nerve. 



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

 posterior border of the long internal lateral ligament, wliile the artery here inclines somewhat 

 backward. Thus the nerve is superficial to the artery for a shoi-t distanc(>, then lies in front of 

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



