Operations for Rectal Cancer
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Measurements of the location of malignancies in the rectum are generally made by placing the patient in the knee- chest position, inserting a proctosigmoido- scope, and reading off the number of centimeters indicated by the markers on the outside of the scope at the point where the perianal skin meets the scope. This measures the distance between the anal verge and the lower border of the tumor where the tip of the proctoscope has been inserted. Remember that when a measurement is cited taking the anal verge as the point of reference, it does not refer to the rectum alone but includes the length of the anal canal in the calculation. The rectal mucosa meet the squamous epithelium of the anal skin at the “dentate line.” This line is 2–3 cm above the anal verge and about 1 cm below the upper border of the sphincter muscles of the anal canal. The length of the anal canal is about 4 cm. All the measurements cited below are made from the reference point of the anal verge.
KeywordsAnal Canal Anal Verge Sphincter Muscle Colorectal Anastomosis Villous Adenoma
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- Parks AG, Thomson JPS (1977) Per-anal endorectal operative techniques. In: Rob C, Smith R (eds) Operative surgery, colon, rectum and anus, 3rd edn. Butterworth, London, p. 157Google Scholar