Pectinate line
Encyclopedia
The pectinate 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:
Hindgut
The hindgut is the posterior part of the alimentary canal. In mammals, it includes the distal third of the transverse colon and the splenic flexure, the descending colon, sigmoid colon and rectum.-Blood flow:...
-proctodeum
Proctodeum
A proctodeum is the back ectodermal part of an alimentary canal. It is created during embryogenesis by a folding of the outer body wall. It will form the lower part of the anal canal, below the pectinate line, which will be lined by stratified squamous non-keratinized and stratified squamous...
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 Lymph Lymph is considered a part of the interstitial fluid, the fluid which lies in the interstices of all body tissues. Interstitial fluid becomes lymph when it enters a lymph capillary... drainage |
internal iliac lymph nodes Internal iliac lymph nodes The internal iliac lymph nodes surround the internal iliac artery and its branches , and receive the lymphatics corresponding to the distribution of the branches of it, i... , inferior mesenteric lymph nodes Inferior mesenteric lymph nodes The inferior mesenteric glands consist of:* small glands on the branches of the left colic and sigmoid arteries* a group in the sigmoid mesocolon, around the superior hemorrhoidal artery... (pararectal lymph nodes Pararectal lymph nodes The pararectal lymph nodes are in contact with the muscular coat of the rectum. They drain the descending iliac and sigmoid parts of the colon and the upper part of the rectum; their efferents pass to the preaortic glands.-External links:... ), |
superficial inguinal lymph nodes Superficial inguinal lymph nodes The superficial inguinal lymph nodes form a chain immediately below the inguinal ligament.They lie deep to Camper's fascia which overlies the femoral vessels at medial aspect of the thigh.... (below Hilton's white line Hilton's white line Hilton's white line is a boundary in the anal canal.Below it, lymphatic drainage is to the superficial inguinal nodes.A landmark for the intermuscular border between internal and external anal sphincter muscles... ) >- | 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 Hindgut The hindgut is the posterior part of the alimentary canal. In mammals, it includes the distal third of the transverse colon and the splenic flexure, the descending colon, sigmoid colon and rectum.-Blood flow:... ) |
stratified squamous epithelium Stratified squamous epithelium A stratified squamous epithelium consists of squamous epithelial cells arranged in layers upon a basement membrane. Only one layer is in contact with the basement membrane; the other layers adhere to one another to maintain structural integrity... , non-keratinized (until Hilton's white line Hilton's white line Hilton's white line is a boundary in the anal canal.Below it, lymphatic drainage is to the superficial inguinal nodes.A landmark for the intermuscular border between internal and external anal sphincter muscles... , where the anal verge becomes continuous with the perianal skin containing keratinized epithelium.) >- | embryological origin |
endoderm Endoderm Endoderm is one of the three primary germ cell layers in the very early embryo. The other two layers are the ectoderm and mesoderm , with the endoderm as the intermost layer... |
ectoderm Ectoderm The "ectoderm" is one of the three primary germ cell layers in the very early embryo. The other two layers are the mesoderm and endoderm , with the ectoderm as the most exterior layer... >- | artery |
superior rectal artery Superior rectal artery The superior rectal artery is an artery that descends into the pelvis to supply blood to the rectum.-Structure:The superior rectal artery is the continuation of the inferior mesenteric artery... |
middle Middle rectal artery The middle rectal artery is an artery in the pelvis that supplies blood to the rectum.-Structure:The middle rectal artery usually arises with the inferior vesical artery, a branch of the internal iliac artery... and inferior Inferior rectal artery The inferior rectal artery is an artery that supplies blood to the lower half of the anal canal.-Structure:The inferior rectal artery arises from the internal pudendal artery as it passes above the ischial tuberosity.... rectal arteries >- | vein |
superior rectal vein Superior rectal vein The inferior mesenteric vein begins in the rectum as the superior rectal vein , which has its origin in the hemorrhoidal plexus, and through this plexus communicates with the middle and inferior hemorrhoidal veins.... |
>- | internal hemorrhoids (not painful) | >- | inferior hypogastric plexus Inferior hypogastric plexus The inferior hypogastric plexus is a plexus of nerves that supplies the viscera of the pelvic cavity.The inferior hypogastric plexus is a paired structure, with each situated on the side of the rectum in the male, and at the sides of the rectum and vagina in the female.-Sources:Contributions to... |
inferior rectal nerves |