Human anus

Human anus
A woman's anus, without pubic hair
Scheme of digestive tract, with anus marked
Details
PrecursorProctodeum
SystemAlimentary
ArteryInferior rectal artery
VeinInferior rectal vein
NerveInferior rectal nerves, pudendal nerve
LymphSuperficial inguinal lymph nodes
Identifiers
Latinanus
TA98A05.7.05.013
TA23022
FMA15711
Anatomical terminology

In humans, the anus (pl.: anuses or ani; from Latin ānus, "ring", "circle")[1][2] is the external opening of the rectum located inside the intergluteal cleft. Two sphincters control the exit of feces from the body during an act of defecation, which is the primary function of the anus. These are the internal anal sphincter and the external anal sphincter, which are circular muscles that normally maintain constriction of the orifice and which relax as required by normal physiological functioning. The inner sphincter is involuntary and the outer is voluntary. Above the anus is the perineum, which is also located beneath the vulva or scrotum.

In part owing to its exposure to feces, a number of medical conditions may affect the anus, such as hemorrhoids.[3] The anus is the site of potential infections and other conditions, including cancer (see anal cancer).[4]

With anal sex, the anus can play a role in sexuality. Attitudes toward anal sex vary, and it is illegal in some countries.[5] The anus is often considered a taboo part of the body,[5] and is known by many, usually vulgar, slang terms. Some sexually transmitted infections including HIV/AIDS and anal warts can be spread via anal sex.

  1. ^ Martim de Albuquerque (1873). Notes and Queries. Original from the University of Michigan: Oxford University Press. p. 119.
  2. ^ O'Reilly, Edward; O'Donovan, John (1864). An Irish-English Dictionary. Original from Oxford University: J. Duffy. p. 7.
  3. ^ Schubert, MC; Sridhar, S; Schade, RR; Wexner, SD (July 2009). "What every gastroenterologist needs to know about common anorectal disorders". World J Gastroenterol. 15 (26): 3201–09. doi:10.3748/wjg.15.3201. ISSN 1007-9327. PMC 2710774. PMID 19598294.
  4. ^ "Anal Cancer". The Lecturio Medical Concept Library. Retrieved 24 July 2021.
  5. ^ a b "Anal Sex, defined". Discovery.com. Archived from the original on June 13, 2002. Retrieved July 23, 2013.