596 INJURIES TO THE RECTUM AND ANAL REGION. 



prominent the anus from pressure of bowel contents, the more un- 

 favourable the condition. In such cases the adhesions must be 

 broken down, taking care in males to protect the urethra and bladder, 

 and in females the vagina. In males a catheter should be introduced 

 into the urethra, in females the index finger of the left hand inserted 

 in the vagina during operation. The first incision is then made, 

 as above described, by either removing a piece of skin with scissors, 

 or making a cross-shaped cut through the skin over the anus, and 

 gradually thrusting a finger or probe into the depths until the lumen 

 of the rectum is attained. The position of the probe or finger in- 

 dicates the proper direction. 



In animals the trocar has been recommended for opening the 

 occluded rectum, but the above method deserves preference. After 

 discharge of faeces, an attempt should be made to suture the mucous 

 membrane to the skin, and recurrence may be prevented by 

 frequently smearing the parts with oil. Clysters assist the bowels 

 in acting for the first few days. 



Howard produced a colic fistula in a sucking pig with atresia 

 recti. The same operation has been practised in man, but being 

 as a rule of no practical value, is now seldom adopted. Treatment 

 of recto-vaginal fistula is described later. 



II.— INJURIES TO THE RECTUM AND ANAL REGION. 



Injuries to the rectum in mares and cows may be caused by the 

 penis during the act of coition, while perforations result from in- 

 cautious exploration of the rectum with the hand, and by the attempts 

 sometimes made by laymen to remove blood from the mucous 

 membrane of the rectum in order to cure colic. The incautious use 

 of clyster syringes may produce wounds ; and injuries are occasionally 

 inflicted on the rectum by persons desiring to revenge themselves 

 on the owner of the animal. 



Less frequently the rectum is ruptured by abnormally large and 

 hard masses of faeces, but in mares and cows during parturition, 

 injuries caused by the foetus, or by violent and awkward attempts 

 at assistance are common, the colt's feet sometimes penetrate the 

 upper wall of the vagina or uterus, and the lower wall of the rectum. 



Finally, any hard substance accidentally swallowed with the 

 food may penetrate the mucous membrane of the rectum or anus 

 and produce proctitis. In dogs, animal or fish bones are a frequent 

 cause. In a horse which had swallowed a large number of fir-needles, 

 Kirchner found inflammation of the rectum caused by the needles 



