Rectum and Anus 387 



In making a digital examination of the rectum the firm os uteri 

 (felt through the anterior wall) must not be mistaken for ' tumour.' 

 If there be any doubt as to the nature of the mass one finger should 

 be passed into the vagina whilst the other remains in the bowel. Nor 

 must the sacro-vertebral angle be taken for a cartilaginous or malig- 

 nant tumour, or for some kind of rectal obstruction. A malignant 

 mass in the rectum, which is just beyond the reach of the finger as 

 the patient lies in bed, may sometimes be detected when the patient is 

 examinee, in the erect position and ' bears down.' 



The dilatability of the anus, and the capacity of the rectum, have 

 occasionally tempted the surgeon to introduce his whole hand into the 

 lower bowel for exploration. The practice is dangerous, even when 

 the hand is small, as the bowel or its peritoneal covering may be torn, 

 whilst the practical result obtained is extremely problematical. More- 

 over, permanent paralysis may follow such rough dilatation of the 

 sphincter. 



By the introduction of the hand after death when permission 

 cannot be obtained for a sectio cadaveris abdominal and even thoracic 

 viscera may be extracted for inspection. 



When hcemorrhage takes place into the rectum no blood may escape 

 by the anus until the pressure within becomes so urgent that evacua- 

 tion can no longer be prevented by the external sphincter. Then an 

 enormous quantity of fluid and clot may come away. Faintness, with 

 a feeling of heat and fulness in the lower bowel after operation, suggest 

 haemorrhage, and demand the introduction of the finger. 



The mucous membrane is but loosely attached by the sub-mucous 

 coat. It is thick and vascular, and when the bowel is empty is thrown 

 into folds. On account of the looseness of its connections it is apt to 

 prolapse, especially in the child who strains at stool on account of 

 vesical calculus, chronic constipation, or diarrhoea. Permanent trans- 

 verse folds have been described as existing where the bowel changes 

 its directions. They might possibly obstruct the introduction of a 

 tube ; their office is to allow free distension. 



The mucous membrane of the large intestine is liable to dysenteric 

 inflammation and ulceration, and cicatrisation of these ulcers produces 

 stricture. The nearer the anus, the greater the liability to ulceration. 

 The disease probably begins in the solitary glands. 



The epithelium is simple columnar ; a rectal epithelioma is, there- 

 fore, of the nature of columnar epithelioma ; sometimes the disease 

 appears as a cord-like constriction. The epithelium at the anus being 

 stratified, the malignant development from it is the squamous epithe- 

 lioma. In an epithelioma occupying both the rectal and anal mucous 

 membrane the elements might be of both varieties. 



There is not always pain with cancer of the rectum, especially when 

 the disease is high up ; but even in this case distress comes on later 

 when the primary disease, or the lymphatic invasion, has involved the 



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