846 



THE NERVOUS SYSTEM OF THE PIG 



The brachial plexus is deriyed from the same nerves as in the ox, but the root 

 furnished by the sixth cervical is relatively smaller. The plexus consists of two 

 parts, the upper of which emerges above the scalenus, the lower between the two 

 parts of that muscle. The more important differences in the nerves emanating 

 from the plexus from the arrangement in the ox occur in the distal part of the limb. 

 The cutaneous branch of the radial nerve divides at the carpus into branches which 

 concur with the dorsal branch of the ulnar nerve in supplying the dorsal digital 

 nerves, two for each digit. The volar digital nerves, also two for each digit, are 

 formed by the terminal branches of the median nerve and the volar or deep branch 

 of the ulnar nerve. The formation and arrangement of the digital nerves are 

 indicated in the annexed schematic figures. 



The lumbo-sacral plexus is derived from the ventral branches of the last three 



Deep peroneal 



nerre 



Superficial 

 peroneal nerre 



Saphenous 

 nerve 



Tibial nerve 



Medial plantar 

 nerve 



Lateral 



plantar 



nerve 



■ Dorsal 



branch 



Anasto- 

 '' molic 

 branch 



Fig. 675. — Nerves of Dist.^l P.4rt of Right Hind 



Li.MB OF Pig; Dorsal View (Sche.m.^tic) . 



p. Dorsal proper digital nerves. 



Fig. 676. — Nerves of Distal Part of Right Hind 



Limb of Pig; Plantar View (Schematic). 



p, Plantar proper digital nerves. 



lumbar and first sacral nerves. The distribution of the branches of the plexus 

 differs chiefly in the distal part of the limb. The superficial peroneal nerve is 

 large and terminates by forming the greater part of the dorsal digital nerves. 

 The latter, two for each digit, are also in part formed by the terminal branches of 

 the deep peroneal nerve. 



The tibial nerve divides at the tarsus into medial and lateral plantar nerves. 

 The latter divide to form the plantar digital nerves, two for each digit. In addi- 

 tion, the lateral plantar nerve supplies a branch to the dorsal aspect of the lateral 

 (fifth) digit. The arrangement of the digital nerves is indicated by the annexed 

 schematic figures. 



The sympathetic system of the pig has received very little attention from 

 anatomists. The anterior cervical ganglion is long and fusiform. It gives off 



