THE NERVOUS SYSTEM OF THE OX 



715 



of the preceding. They accompany the utero-ovarian arteries to the ovary and the 

 cornua of the uterus. 



The hypogastric or pelvic plexus (P. hypogastricus) is the pelvic continuation 

 of the aortic and posterior mesenteric plexuses. The chief nerves which form it 

 enter the pelvic cavity ventral to the large vessels, anastomose with each other and 

 with branches from the third and fourth sacral nerves, and ramify on the pelvic 

 viscera. The peripheral plexuses derived therefrom are named according to the 

 organs which they supi:)ly; the chief of these are the haemorrhoidal, vesical, utero- 

 vaginal, prostatic, cavernous (of the penis or clitoris). 



THE NERVOUS SYSTEM OF THE OX^ 



The spinal cord resembles that of the horse in conformation and structure. 

 In cattle of medium size its length is about 165 to 170 cm. (ca. 65 to 67 inches) and 

 its weight about 240 to 250 grams 

 (ca. 8 ounces). 



In a cow 140 cm. in heiglit Dcxler 

 found tlio weight of the cord (inchiding 

 the intr;ukiral nerv(»-roots) to be 2()0 g. 

 and the length lt)2 cm. The lengths of 

 the regions were: cervical 41 cm., tho- 

 racic 72 cm., lumbar 32 cm., sacral 7 cm. 



The brain has an average 

 weight of about 500 grams (ca. 

 16 to 17 ounces). Its differences 

 in general form are correlated with 

 those noted in the consideration of 

 the cranial cavity. 



The medulla is short, wide, 

 and thick. Its ventral face is 

 strongl}^ convex. The pj'ramids 

 are narrow, short, and close to- 

 gether in front. Near the decus- 

 sation there is a well-defined oval 

 prominence on either side which 

 indicates the position of the pos- 

 terior olive. The corpus trape- 

 zoideum is large; it has no cen- 

 tral part between the pyramids. 

 The external arcuate fibers are 

 distinct. The restiform bodies are 

 short and thick and diverge more 

 strongly tha.n in the horse. The 

 floor of the fourth ventricle is only 

 about two-thirds as long as in the 

 horse. The area acustica is a well- 

 marked oval prominence lateral to 

 the middle part of the limiting sul- 

 cus. The tuberculum acusticum 



at the origin of the auditory nerve is very large. The anterior fovea is distinct. 

 The posterior recess of the fourth ventricle communicates through the foramen of 

 Magendie (Apertura mediana) with the subarachnoid space. 



1 Only the most salient differences as compared with the horse will be mentioned. 



Fig. 528. — Brain of Cow, Dorsal View. 

 ^, Sulcus transversus; .3, longitudinal fissure; 3, antero- 

 internal frontal gyrus; 4, olfactory bulb; 5, marginal or sagittal 

 pole of hemisphere; 6, lateral fissure (of Sylvius); 7, hemisphere 

 of cerebellum; S, vermis of same; 9, accessory nerve; W, dorsal 

 root of first cervical nerv% (Ellenberger-Baum, Anat. d. Haus- 

 tiere.) 



