Anal canal
Canalis analis
DigestiveOrgansPelvis
- What it is
- Last 3-4 cm of the gut. At the anorectal junction the puborectalis sling pulls the gut forward, and the canal then runs down and back through the pelvic floor to the anus.
- Function
- Keeps faeces and gas in with the internal (involuntary) and external (voluntary) anal sphincters, relaxing during defecation.
- Size
- About 3-4 cm long.
- Clinical note
- The pectinate (dentate) line marks an embryological boundary: haemorrhoids above it are painless, those below it painful, because of different nerve supply.