| Pectinate line | |
| Latin: | linea pectinata, linea anocutanea |
The pectinate line (dentate line) is a line which divides the upper two-thirds and lower third of the anal canal. Developmentally, this line represents the hindgut-proctodeum junction.
It is an important anatomical landmark in humans, and several distinctions can be made based upon the location of a structure relative to this line:
| Distinction | Above pectinate line | Below pectinate line | - | Lymph drainage | internal iliac[1] | superficial inguinal lymph nodes (below Hilton's white line) | - | columnar epithelium (as is most of the digestive tract - the line represents the end of the part of the body derived from the hindgut) | stratified squamous epithelium, non-keratinized (until Hilton's white line, where the anal verge becomes continuous with the perianal skin containing keratinized epithelium.) | - | Embryological origin[2] | - | middle and inferior rectal arteries | - | superior rectal vein draining into the inferior mesenteric vein and subsequently the hepatic portal system | middle and inferior rectal veins | - | Hemorrhoids classification | internal hemorrhoids (not painful) | external hemorrhoids (painful) | - | Nerves | inferior hypogastric plexus | pudendal nerves |
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