Overview Of Anal Problems and Rectal Problems
The rectum is the last section of the large intestine where stool get stored till the time of its expulsion from the body. The anus is the opening of the rectum, through which the stored stool is expelled from the body.
The anus is partially derived from the ectoderm from which the outer skin and lining of the sense organs are formed, and partially from the intestinal tissue. Rectum, being a part of the intestine, is lined with the same mucosal layer as the rest of the digestive system. Rectum is sensitive to stretching but not pain but the anus and the skin around it have nerves which make them extremely sensitive.
The blood supply to the rectum and anus is through superior and inferior rectal arteries; rectal veins drain the blood from the rectum and anus into the larger portal vein, which goes into the liver before joining the rest of the general circulation. The lymph vessel drainage takes two routes; those from rectum draining into the internal iliac lymph nodes in the lower abdomen while those from the anus drain into the superficial inguinal lymph nodes in the groin.
The anal sphincter is ring-shaped muscle which keeps the anus in a tightly closed condition except at the time of a motion. The autonomic nervous system controls the opening and closing of the anal sphincter and it is not under the control of will, except for the lower part, which can be actively controlled by conscious will.
There are a number of anal problems and rectal problems that can be seen in patients. Some of them are anorectal fistula, anorectal abscess, anal fissure and hemorrhoids. Proctitis, pilonidal disease, levator syndrome and rectal prolapse are some others. Anal and colorectal cancers also may occur. A physical examination of the anus is necessary to diagnose any abnormality. Doctor may insert a gloved finger into the rectum and probe its wall to look for any abnormality. Manual rectal examination of women can be done along with vaginal examination.
An anoscope or proctoscope can be used to get a clear picture of the anus and rectum. Since the proctoscope is rigid, it can be used only for viewing the rectum which is a straight structure. Sigmoidoscope is a flexible viewing tube which can be guided further into the large intestine. Sigmoidoscopy and anoscopy may be done without anesthesia as they are not painful procedures. However, if the discomfort cannot be tolerated, either regional or local anesthesia may be used. It can be performed under general anesthesia too. Enema may be given prior to sigmoidoscopy to flush out the contents of the large intestine. Tissue for biopsy of the lining of both the large intestine and the rectum can be collected with the help of sigmoidoscope. An x-ray examination after giving barium enema will show abnormalities in the rectum and anus.
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Yasser Elnahas
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