386 



The Rectum 



nearly an inch deep, the internal sphincter ; its upper border forms a 

 definite ridge beneath the mucous membrane, and just above it an 

 ulcer or the opening of a fistula is often found. 



The external sphincter (striated) is attached to the coccyx, and, 

 passing around the sides of the anus, its fibres join again to reach the 

 central tendon. It is under control of the will. It is supplied by 

 branches of the inferior hnemorrhoidal vessels and nerves, and by 

 twigs from the fourth sacral. It is advisable to forcibly dilate the 

 sphincter after operating for internal piles, as the temporary paralysis 

 which follows ensures perfect rest and freedom from spasm. 



Fissure of the anus is a linear ulcer or crack which extends from 

 just within the anus to the exterior. On account of its passing across 

 the fibres of the external sphincter the sensory filaments in its depths 

 are disturbed after every act of defecation by the spasmodic contrac- 

 tion of the sphincter, whilst the anus itself is kept tightly occluded. 

 Hence the pain is intense, and it often lasts for hours after stool. 

 Before the ulcer can heal, temporary paralysis of the sphincter must be 

 obtained, either by forcible dilatation, or by section of the superficial 

 fibres. Spasmodic contraction of the sphincter may be due to the 

 presence of a fissure which is so small as to escape detection. By 

 obtaining the temporary paralysis of the muscle in an obscure case 

 relief may generally be secured. 



Spasmodic contraction of the sphincter is very characteristic of 

 ulceration at or near the anus. Irritation of sensory filaments of the 

 internal pudic nerve involves a message of unrest to the grey matter of 

 the lumbar enlargement of the cord, which is there converted into a 

 motor stimulus leaving by those fibres of the nerve which supply the 

 muscle guarding the mucous orifice. Sometimes the pain is so severe, 

 and the sensory impulse is so energetic, that the adjacent cells in the 

 posterior part of the grey crescent are thrown into sympathetic vibra- 

 tion, and the patient complains of pains in the regions near those from 

 which the afferent nerves are coming ; thus he may have neuralgia 

 in the back (lumbago ?), down the thigh (sciatica ?), or along the scro- 

 tum. And^sometimes the efferent (motor) impulse is so severe that the 

 testicles may be drawn up, or the bladder spasmodically evacuated ; 

 vaginismus also may be set up, or contraction of the sphincter vesicae, 

 retention of urine being the result. 



By inspection of the anus information may sometimes be obtained 

 as to the nature of rectal disease ; thus in the case of fissure it is tightly 

 closed, and only with difficulty can a search be made amongst the 

 muco-cutaneous folds and furrows. But when obstruction exists, as 

 in the case of simple or malignant stricture, or of a greatly enlarged 

 prostate, the sphincter becomes atrophied and weak from want of use, 

 and the anus flaccid and patulous. This is very characteristic. Even 

 in the case of annular constriction of the sigmoid flexure I have found 

 the anus flabby and patulous. (See also p. 384.) 





