Measurement of Anal Canal in Japanese

Abstract

In the literatures, the term "anal canal" has often been used without clear definition causing much confusion among the leaders.There are two "anal canal", one is surgical anal canal ranging from anal verge to the upper edge of levator muscle and the other is anatomical anal canal ranging from anal verge to dentate line. The former may be called sphincteric anal canal and the latter anodermal anal canal.The progress of colopctology is now requiring. clear definition of the anal canal and the committee of rules for the management of colonic cancer specimen defined "anal canal" as surgical anal canal.For thr the practice of anorectal lesions however, both of them are eqivalently important; surgical anal canal is concerned with the anatomy, function and measurent of sphincteric muscles, the extent of fisulas and sphincter-preserving operation of rectal cancer etc. On the other hand, anatomical anal canal is concerned with the development, diagnosis and treatment of various anal lesions etc.It is therefore desirable to observe and describe every anal or rectal lesions in connection with 3 the landmarks of anal verge, dentate line and upper edge of levator. However, observation and description of the lesions are liable to be done only with one of the landmarks, because each of them is perceived by the different sensation of tactile, anoscopic and visual sensation respectively. In a case of rectal cancer for example, the location is described with the distance from anal verge at tke time of preoperative endoscopic examination. At operation, the location is scrutinized as the distance from the upper edge of levator for the persuit of preserving sphincters. In the resected specimen, the location is measured as the distance from dentate line.The above description shows the importance of understanding, mesasurement and standard figures of both surgical and anatomical anal canal.Measurement of both values were performed by us with 140 male and 32 female Japanese adults who received health check. Both values were measued as follows; the posterior aspect of the anus was opend and visualized with Strange's anoscope. The top of a metallic sound was rectangularly twisted and fooked on the upper edge of levator mid-posteriorly. Two tiny rubber rings were threaded to the sound and each of them was shifted according to the level of dentate line and anal verge.The results are shown in the following table.Surg. Anal CanalAnat. Anal CanalMale3.2cm1.8cmFemale2.9cm1.7cmAt the time of presentation, those vlaues will be discussed also in connection with corpulence ane histology.