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THE NERVOUS SYSTEM OF THE PIG 



The cranial nerves ]ir('sont the following; sjiccial features: 



The third, fourth, sixth, and the ophthahnic and maxillary divisions of the 

 fifth nerve, emerge together as in the ox. 



Tlie lacrimal nerve resembles that of the horse, the frontal that of the ox. 

 The naso-ciliary nerve is relatively large and sends numerous filaments to the ocular 

 muscles. Th(^ maxillary nerve has a very short course in the pterygo-palatinc 

 fossa. The infraorbital nerve is large in correlation with the development of the 

 snout which receives numerous branches. The mandibular nerve emerges through 

 the foramen lacerum anterius. The superficial temporal nerve is small; according 

 to Moussu it furnishes the excito-secretory fil)ers to the upper part of the parotid 

 gland, while those going to the lower part are derived from the mylo-hyoid nerve. 



The inferior buccal nerve passes downward and forward under cover of the 



Ulnar nerve 

 {dorsal branch) 



Anastomotic 

 branch 



MediiiH 



Ulnar nerve 

 'Dorsal branch 



branch 



Fig. 535. — Nerves of Dist.\l P.\rt of Right Fore 



Limb of Pig, Anterior View (Schem.^tic). 



c, Dorsal common digital nerves; p, dorsal proper 



tligital nerves. 



Fig. 536. — Nerves of Dist.\l P.\rt of Right Fore 



Limb of Pig, Posterior View (Schem.\tic). 



p, Volar proper digital nerves. 



parotid gland and accompanies the parotid duct, with which it tiu'ns around the 

 lower border of the jaw in front of the masseter. 



The vagus bears a jugular ganglion and a ganglion nodosum ; the latter occurs 

 at the point of origin of the sui^erior laryngeal nerve, and may be as large as a small 

 pea. Proximal to this the vagus is easily divided into two strands, one of which is 

 the accessory component. The oesophageal trunks form a posterior oesophageal 

 plexus, as in man, from which two nerves issue. The inferior nerve is small and 

 ramifies on the parietal surface of the stomach. The superior trunk is much larger; 

 it gives branches to the stomach, crosses the lesser curvature of that organ, and 

 joins the solar i)lexus. 



The hypoglossal nerve may present a small dorsal root, on which there is a 

 minute hypoglossal ganglion (of Froriep). 



