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==General== | ==General== | ||
*Present in the transformation zone between the columnar epithelium of the [[rectum]] and squamous epithelium of the [[anus]] - similar to the transformation zone of the [[uterine cervix]].<ref name=pmid20436833>{{Cite journal | last1 = Pineda | first1 = CE. | last2 = Welton | first2 = ML. | title = Management of anal squamous intraepithelial lesions. | journal = Clin Colon Rectal Surg | volume = 22 | issue = 2 | pages = 94-101 | month = May | year = 2009 | doi = 10.1055/s-0029-1223840 | PMID = 20436833 }}</ref> | *Present in the transformation zone between the columnar epithelium of the [[rectum]] and squamous epithelium of the [[anus]] - similar to the transformation zone of the [[uterine cervix]].<ref name=pmid20436833>{{Cite journal | last1 = Pineda | first1 = CE. | last2 = Welton | first2 = ML. | title = Management of anal squamous intraepithelial lesions. | journal = Clin Colon Rectal Surg | volume = 22 | issue = 2 | pages = 94-101 | month = May | year = 2009 | doi = 10.1055/s-0029-1223840 | PMID = 20436833 }}</ref> | ||
Anatomy & histology: | |||
*Typically, the squamocolumnar junction is just above the dentate line (also ''pectinate line''). | |||
*Squamous epithelium 1 cm proximal to the dentate line is considered abnormal.<ref name=pmid11174313>{{Cite journal | last1 = Bujanda | first1 = L. | last2 = Iriondo | first2 = C. | last3 = Muñoz | first3 = C. | last4 = Etxezarraga | first4 = C. | last5 = Ramírez | first5 = MM. | last6 = Ramos | first6 = F. | last7 = Sánchez | first7 = A. | title = Squamous metaplasia of the rectum and sigmoid colon. | journal = Gastrointest Endosc | volume = 53 | issue = 2 | pages = 255-6 | month = Feb | year = 2001 | doi = | PMID = 11174313 }}</ref> | |||
*The dentate line divides the anal canal into upper two thirds and lower third. | |||
==Microscopic== | ==Microscopic== |
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