Human anus

Human anus
A woman's anus, without pubic hair
File:Male human anus close-up.jpg A man's anus
Details
Precursor	Proctodeum
System	Alimentary
Artery	Inferior rectal artery
Vein	Inferior rectal vein
Nerve	Inferior rectal nerves, pudendal nerve
Lymph	Superficial inguinal lymph nodes
Identifiers
Latin	anus
MeSH	D001002
TA	A05.7.05.013
FMA	15711
Anatomical terminology

 

In humans, the anus (plural: anuses) is the outer opening of the rectum (where the poop is stored), found between the buttcheeks (buttocks). Its main job is to let poop leave the body during pooping. The anus has two muscles called sphincters that control this process:

1. The inner sphincter (works automatically, without you thinking about it).
2. The outer sphincter (you can control this one).

These muscles are normally tight to keep the anus closed, but they relax when you need to poop. Above the anus is an area called the perineum, which is also below the vulva (in females) or the scrotum (in males).

Because the anus comes into contact with poop, it can be affected by several medical conditions, such as hemorrhoids (piles). The anus is also a place where infections and other problems, including anal cancer, can happen.

The anus can be involved in sexual activity, such as anal sex. People have different opinions about anal sex, and in some countries, it is even illegal. The anus is often seen as a taboo body part and is referred to by many slang terms, which are usually vulgar. Anal sex can also spread certain sexually transmitted infections (STIs), such as HIV/AIDS and anal warts.

A front-view cut of the human anus.

The anus is the last part of the digestive system, connecting directly to the rectum and passing through the pelvic floor. It is surrounded by two muscle rings called the internal and external anal sphincters, which control bowel movements. The anus has folds called anal valves, which meet at a line known as the pectinate line. This line marks the boundary between two types of tissue: the inner lining (mucosa) of the rectum and the outer skin. It also separates the internal anus (above the line) from the external anus (below the line).

The anus recieves blood from the inferior rectal artery and is controlled by nerves called the inferior rectal nerves, which come from the pudendal nerve.

See also

• Anal bleaching
• Anal stage (Freudian psychosexual stage)
• Anococcygeal nerve
• Anorectal disorder
• Buttocks
• Cloaca
• Coccydynia
• Coccyx
• Flatulence