Pectinate line

Pectinate line

Pectinate line
Pectinate line labeled at bottom center.
The interior of the anal cami and lower part of the rectum, showing the columns of Morgagni and the anal valves between their lower ends. (Pectinate line visible but not labeled.)
Latin Linea pectinata, linea anocutanea

The pectinate line (dentate line) is a line which divides the upper 2/3s and lower 1/3 of the anal canal. Developmentally, this line represents the hindgut-proctodeum junction.

It is an important anatomical landmark, and several distinctions can be made based upon the location of a structure relative to this line:

Distinction Above pectinate line Below pectinate line
destination of lymph drainage internal iliac lymph nodes,[1] inferior mesenteric lymph nodes[2] (pararectal lymph nodes), superficial inguinal lymph nodes (below Hilton's white line)[3]
epithelium 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 endoderm ectoderm
artery superior rectal artery middle and inferior rectal arteries
vein superior rectal vein middle and inferior rectal veins
hemorrhoids classification internal hemorrhoids (not painful) external hemorrhoids (painful)
nerves inferior hypogastric plexus inferior rectal nerves

Additional images


External links

  • eMedicine Dictionary
  • rectum)