Pectinate line

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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

Microscopic cross section of the anorectal junction.
Anatomy of the anus and rectum
Coronal section of rectum and anal canal.

References

↑ Anne M. R. Agur; Moore, Keith L. (2006). Essential Clinical Anatomy (Point (Lippincott Williams & Wilkins)). Hagerstown, MD: Lippincott Williams & Wilkins. p. 258. ISBN 0-7817-6274-X.
↑ "Dissector Answers - Pelvis & Pelvic Viscera". Retrieved 2007-12-09.
↑ "Pelvis". Retrieved 2007-12-09.

External links

Pectinate+line at eMedicine Dictionary
pelvis at The Anatomy Lesson by Wesley Norman (Georgetown University) (rectum)

Anatomy of torso, digestive system: Gastrointestinal tract, excluding mouth (TA A05.3–7, TH H3.04.02-04, GA 11.1141)

Upper GI

Hypo- pharynx	Piriform sinus spaces: Peripharyngeal space Retropharyngeal space Parapharyngeal space Retrovisceral space Retropharyngeal space Danger space Prevertebral space Pterygomandibular raphe Pharyngeal raphe Buccopharyngeal fascia Pharyngobasilar fascia Pharyngeal muscles

Esophagus	UES LES Esophageal glands Serosa / Adventitia Muscular layer Submucosa Mucosa Muscularis mucosa

Stomach	by region: Greater curvature Lesser curvature Angular incisure Cardia Body Fundus Pylorus antrum canal sphincter by layer: Serosa Muscular layer Submucosa Gastric mucosa Muscularis mucosa Gastric rugae Gastric pits Gastric gland Cardiac glands Fundic glands Pyloric glands Goblet cell

Lower GI

Intestine: small

Layers	Serosa Subserosa Muscular layer Circular folds Submucosa Mucosa Muscularis mucosa Peyer's patches Intestinal villus Intestinal gland

Duodenum	Suspensory muscle Major duodenal papilla Minor duodenal papilla Duodenal cap Duodenojejunal flexure Brunner's glands

Jejunum	no substructures

Ileum	Terminal ileum Ileocecal valve

Intestine: large

Layers	Serosa Subserosa Muscular layer Submucosa Mucosa

Cecum	Vermiform appendix

Colon	ascending colon hepatic flexure transverse colon splenic flexure descending colon sigmoid colon continuous taenia coli haustra epiploic appendix

Rectum	Transverse folds of rectum Rectal ampulla

Anal canal	Anal columns Anal valves Anal sinuses Pectinate line Sphincter ani internus muscle Intersphincteric groove Sphincter ani externus muscle Anus

M: DIG

anat (t, g, p)/phys/devp/enzy

noco/cong/tumr, sysi/epon

proc, drug (A2A/2B/3/4/5/6/7/14/16), blte

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