428 Volvulus and Torsion of the Intestine. 



Predisposing causes always play an important part in con- 

 nection with the immediate exciting causes. As sucli may be 

 mentioned heavy filling of the left divisions, especially of the 

 pelvic flexure, with fecal masses, dry masses of feces, sand or 

 calculi, while the transverse divisions are filled less completely; 

 also the stronger filling of the right upper division and, accord- 

 ing to Forssell, a stronger filling of the left lower division, the 

 presence of a tumor in the wall of the intestines; a minor de- 

 gree of filling of the other portions of the bowel ; also probably, 

 the variable condition of the stomach as to a greater or a lesser 

 degree of filling and a relaxation of the abdominal wall. Forssell 

 also called attention to it that a predisposing cause is furnished 

 in some horses by the comparatively large mesentery between 

 the divisions at the pelvic flexure. 



If the divisions of the colon are tilled nniformly with firm feces or if they are 

 bloated uniformly, torsion cannot occur. In such cases the internal abdominal 

 pressure is much increased and the free movements of the intestines are inhibited 

 proportionately ; uniformly distributed voluminous contents of the bowel or a great 

 tension of the wall do not permit a decrease of the intestinal lumen or a compres- 

 sion of the vessels, and these factors are necessary for the production of torsion. 

 In cases where ol>servers have believed torsion to have occurred in consequence of 

 bloating, they were evidently mistaken; torsion occurred first and bloating later on 

 as a consequence. 



Torsion of the cecum around its long axis is very rare, and 

 it is probably also caused by the mechanical influences pointed 

 out above. The shortness of the cecum when compared with the 

 colon and the position of the former, fully explain why displace- 

 ments of the cecum should be so rare. 



Volvulus or torsion of the small intestine or of the small 



colon have a much more complicated mechanism. Torsion may 

 be brought about by a loop of intestine with its mesentery be- 

 coming twisted around another loop, the latter with its mesen- 

 tery forming the axis (volvulus, formation of a nod, volvulus 

 nodosus), or by a longer loop turning around its own mesentery 

 (axial torsion, volvulus mesenterialis). In some cases the whole 

 small intestine of the horse, or the whole colon in the hog may 

 be twisted around the larger omentum with its mesentery, par- 

 ticularly if the body performs very abrupt motions, if the ani- 

 mal throws itself around or is rolled, as occurs frequently in 

 the unloading of hogs and calves. The production of torsion 

 is favored if the intestines contain an abundance of liquid or 

 dry feces or sand (Glage), or if they are the seat of a tumor. 

 However, total or even partial torsion of the mesentery is quite 

 rare. 



Especially in horses one observes more frequently entan- 

 gling or volvulus of the small intestines alone; loops of small 

 intestines are very rarely twisted around the colon or cecum or 

 around the small colon, while loops of the small colon rarely be- 

 come twisted themselves. In many of these cases, reckless, ex- 



