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DIGESTIVE SYSTEM OF THE HORSE 



flexure of the great colon; ventrally to the bladder (when full) or to the uterus,. 

 The second part of the rectum is related dorsally and laterally to the pelvic wall. 

 Ventrally the relations differ in the two sexes. In the male they are the bladder, 

 the terminal parts of the ductus deferentes, the vesicute seminales, the prostate, 

 the bulbo-urethral glands and the urethra. In the female they are the uterus, 

 vagina, and vulva. ^ 



Structure of the Large Intestine 

 The serous coat covers the different parts in varying degree. It does not 

 cover (a) the opposed surfaces of the cfficum and colon which are between the layers 



.J 



Fig. 369. — Topography op Viscera of Mare; Left Deep View. 

 IR., First thoracic vertebra: IL., first lumbar vertebra; 2K., second sacral spine; S., scapula; A., humeruB; 

 B., ilium; F., femur; Sch., pubis; Si., ischium; L., liver (left lobe); Ma., stomach, the posterior contour of which is 

 indicated by dotted line x; Mi., spleen; Z.A^., left kidney , concealed part indicated by dotted line ; ikT., small colon; D., 

 small intestine, parts of which have been removed; l.d.C, left dorsal colon; l.v.C, left ventral colon; v.Q., sternal 

 flexure; d.Q., diaphragmatic flexure; O., left ovary; (/., horn of uterus; L.i., broad Hgament of uterus; iV/'., rectum; T'., 

 vagina; H., bladder; a, left ventricle; a', right ventricle; b, left coronary artery with descending (b') and circumflex 

 (&") branches; c, left auricle ; d, pulmonary artery (cut) ; e. aorta; /, ligamentum arteriosum; 3, brachiocephalic trunlc 

 (anterior aorta); A, trachea; i, cesophagus; ft, left phrenic nerve; ^, diaphragm in median section; m, uterine tube; 

 n, bursa ovarica; 0, urethra; p, cut edge of broad ligament ; (i, line of reflection of pelvic peritoneum; r, recto-coccygeus; 

 5, suspensory ligament of rectum: t, sphincter ani internus; u, sacro-coccygeus ventralis; v, abdominal wall in section; 

 w, xiphoid cartilage. (After Ellenberger, in Leisering's Atlas.) 



of the cseco-colic fold and mesocolon; (b) the areas of parietal attacament of the 

 caecum and colon ; (c) the retroperitoneal part of the rectum. 



The muscular coat consists of longitudinal and circular fibers. The bulk of 

 the former is in the bands of the caecum and colon. It is to be noted, however, 

 that the bands of the caecum and the ventral parts of the great colon are largely 

 composed of elastic tissue. The bands of the dorsal parts of the colon are largely 

 muscular, and those of the small colon are almost entirely muscular. Some of the 

 circular fibers pass from one part of the colon to another, where they are attached 

 to each other, forming the fibrse transversae coli. The muscular coat of the ampulla 

 of the rectum presents special features. The longitudinal layer of fibers is very 



1 The anterior part of the rectum is variable in position and relations. The amount covered 

 by peritoneum dorsally and laterally is very variable, and appears to be in inverse proportion to 

 the fulness of the bowel. 



