View source for Rectal



==Overview==
{{Infobox Anatomy |
  Name         = {{PAGENAME}} |
  Latin        = |
  GraySubject  = 249 |
  GrayPage     = 1183 |
  Image        = Anorectum.gif |
  Caption      = Anatomy of the anus and rectum |
  Image2       = Gray1077.png |
  Caption2     = The posterior aspect of the rectum exposed by removing the lower part of the sacrum and the coccyx. |
  Precursor    = [[Hindgut]] |
  System       = |
  Artery       = [[middle rectal artery]], [[inferior rectal artery]]  |
  Vein         = [[middle rectal veins]], [[inferior rectal veins]]  |
  Nerve        = [[inferior anal nerves]], [[inferior mesenteric ganglia]]<ref>{{GeorgiaPhysiology|6/6ch2/s6ch2_30}}</ref> |
  Lymph        = [[internal iliac lymph nodes]] |
  MeshName     = Rectum |
  MeshNumber   = A03.556.124.526.767 |
  DorlandsPre  = r_05 |
  DorlandsSuf  = 12697487  |
}} 	
{{SI}}
The '''rectum''' (from the Latin ''rectum intestinum'', meaning ''straight intestine'') is the final straight portion of the [[large intestine]] in some [[mammal]]s, and the [[Gastrointestinal tract|gut]] in others, terminating in the [[anus]]. The human rectum is about 12 cm long. At its commencement its caliber is similar to that of the [[sigmoid colon]], but near its termination it is dilated, forming the [[rectal ampulla]].

== Role in human defecation ==

The rectum intestinum acts as a temporary storage facility for feces. As the rectal walls expand due to the materials filling it from within, stretch receptors from the [[nervous system]] located in the rectal walls stimulate the desire to [[defecation|defecate]]. If the urge is not acted upon, the material in the rectum is often returned to the [[Colon (anatomy)|colon]] where more water is absorbed. If defecation is delayed for a prolonged period, [[constipation]] and hardened feces results.

When the rectum becomes full the increase in intrarectal pressure forces the walls of the [[anal canal]] apart allowing the fecal matter to enter the canal. The rectum shortens as material is forced into the anal canal and [[peristalsis|peristaltic wave]]s propel the feces out of the rectum. The internal and external [[sphincter]] allow the faeces to be passed by muscles pulling the anus up over the exiting feces.

==Medical procedures==
For the diagnosis of certain [[ailment]]s, a [[rectal exam]] may be done. 

[[Suppository|Suppositories]] may be inserted into the rectum as a [[route of administration]] for [[medicine]]. 

The [[endoscopy|endoscopic]] procedures [[colonoscopy]] and [[sigmoidoscopy]] are performed to diagnose diseases such as [[cancer]]. 

===Temperature taking===
[[Body temperature]] can also be taken in the rectum. Rectal temperature can be taken by inserting a [[mercury thermometer]] for 3 to 5 minutes, or a digital [[thermometer]] until it "beeps", not more than 25 mm (1 inch) into the rectum via the [[anus]]. Due to recent concerns related to [[mercury poisoning]], the use of mercury thermometers is now discouraged. Normal rectal temperature generally ranges from 36 to 38 °C (97.6 to 100.4 °F) and is about 0.5 °C (1 °F) above oral (mouth) temperature and about 1 °C (2 °F) above [[axillary]] ([[armpit]]) temperature.

Many [[pediatrics|pediatricians]] recommend that parents take [[infants]] and [[toddler]]'s temperature in the rectum for two reasons: 
* (1) Rectal temperature is the closest to core body temperature and in children that young, accuracy is critical. 
* (2) Younger children are unable to cooperate when having their temperature taken by mouth (oral) which is recommended for children, ages 6 and above and for adults. 

In recent years, the introduction of ear (tympanic) thermometers and changing attitudes on [[privacy]] and [[modesty]] have led some parents and doctors to discontinue taking rectal temperatures.

== Sexual stimulation ==
Due to the proximity of the anterior wall of the rectum to the [[vagina]] in females or to the [[prostate]] in males and the shared nerves thereof, rectal [[stimulation]] or penetration can result in [[sexual arousal]]. For further information on this aspect, see [[anal sex]].

==Additional images==
<gallery>
 Image:Illu repdt female.jpg|Organs of the [[Sex organ|female reproductive system]].
 Image:Gray403.png|Median sagittal section of pelvis, showing arrangement of fasciæ.
 Image:Gray539.png|The arteries of the pelvis.
 Image:Gray1082.png|Section of [[mucous membrane]] of human rectum. X 60.
 Image:Gray1083.png|The [[blood vessel]]s of the rectum and anus. 
 Image:Gray1228.png|Median sagittal section of male pelvis.
 Image:Gray1230.png|Median sagittal section of female pelvis.
 Image:WeiblichesBeckenMedian.gif|Sagittal section of the lower part of a female trunk, right segment.
 Image:Penis.svg|The rectum can be seen the left of this illustration. 
 Image:Rectum.JPG|Cross section microscopic shot of the rectal wall.
</gallery>

==See also== 
* [[Gastrointestinal tract]]
* [[Rectal prolapse]]
* [[Latus rectum]] ([[conic section]])
* [[Semi-latus rectum]] (conic section)
* [[pectinate line]]

==References==
<references/>

==External links==
* {{ViennaCrossSection|pembody/body15a}}
* {{ViennaCrossSection|pelvis/pelvis-e12-15}}
* {{SUNYAnatomyImage|7|8|08}}
* {{SUNYAnatomyLabs|43|11|01|01}} - "The Female Pelvis: The Rectum"
* [http://www.kmle.com/search.php?Search=rectum KMLE Medical Dictionary definition of rectum] retrieved from [http://www.kmle.com KMLE Medical Dictionary] on 2007-03-25


{{digestive_system}}
{{human anatomical features}}

[[Category:Digestive system]]
[[Category:Pelvis]]

[[ar:مستقيم]]
[[cs:Konečník]]
[[da:Endetarm]]
[[de:Mastdarm]]
[[dv:ފުރަގަސް ފަރާތް]]
[[es:Recto]]
[[eo:Rektumo]]
[[fr:Rectum]]
[[io:Rektumo]]
[[id:Rektum]]
[[is:Endaþarmur]]
[[it:Retto]]
[[he:חלחולת]]
[[la:Rectum]]
[[lt:Tiesioji žarna]]
[[nl:Endeldarm]]
[[ja:直腸]]
[[no:Endetarmen]]
[[pl:Odbytnica]]
[[pt:Recto]]
[[ro:Rect]]
[[ru:Прямая кишка человека]]
[[simple:Rectum]]
[[sk:Konečník]]
[[fi:Peräsuoli]]
[[sv:Ändtarm]]
[[tl:Tumbong]]
[[te:పురీషనాళము]]
[[zh:直肠]]

{{WH}}
{{WS}}