Anatomical terminology. 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..
Hereof, how far up is the dentate line?
The anal canal is completely extraperitoneal. The length of the anal canal is about 4 cm (range, 3-5 cm), with two thirds of this being above the pectinate line (also known as the dentate line) and one third below the pectinate line.
Also, why Pectinate line is called watershed line? The dentate (pectinate) line separates the anal canal into an upper and lower parts, not only in structure but also in neurovascular supply (reflecting the differing embryological origin). Note that the dentate line is a "watershed area" and that the exact transition of epithelium and neurovascular supply is varied.
Consequently, where is the dentate line located?
The location of the anal valves corresponds to the dentate line (also known as the pectinate line) located at the midpoint of the surgically defined anal canal. The dentate line corresponds, generally, to the squamocolumnar junction.
What is Hilton's line?
Intersphincteric groove or Hilton's white line is a boundary in the anal canal. Below it, lymphatic drainage is to the superficial inguinal nodes. Hilton's white line is slightly below the pectinate line, a landmark for the intermuscular border between internal and external anal sphincter muscles.
Related Question Answers
What is the Anoderm?
Medical Definition of anoderm : the epithelium lining the anal canal Anal fissures are painful tears in the squamous epithelium of the anus (anoderm) . —What is the function of the rectum?
Function. The rectum is the last stop before the feces is eliminated through the anal canal. Similar to the colon electrolytes are absorbed (sodium, potassium, chloride) and indigestible food ingredients are decomposed by anaerobic bacteria. The stool is thickened through water absorption and mixed with mucus.How big is the rectum?
The average length of the human rectum may range between 10 and 15 cm. Its diameter can be compared to that of the sigmoid colon (the part of the large intestine nearest the rectum) at its onset. However, it becomes larger near the anus, where it forms the rectal ampulla.Are internal hemorrhoids painful?
Hemorrhoids. Hemorrhoids are swollen veins in your lower rectum. Internal hemorrhoids are usually painless, but tend to bleed. External hemorrhoids may cause pain.Why external hemorrhoids are painful?
External hemorrhoids are the most uncomfortable, because the overlying skin becomes irritated and erodes. If a blood clot forms inside an external hemorrhoid, the pain can be sudden and severe. You might feel or see a lump around the anus. 
