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 forms the boundary between the anal canal and the rectum according to the anatomic definition.

[1] Colorectal surgeons instead define the anal canal as the zone from the anal verge to the anorectal ring (palpable structure formed by the external anal sphincter and the puborectalis muscle).

[1] Several distinctions can be made based upon the location of a structure relative to the pectinate line: