Sigmoid colon 246027 222947087 2008-07-01T21:31:56Z 79.31.113.74 {{Infobox Anatomy | Name = {{PAGENAME}} | Latin = colon sigmoideum | GraySubject = 249 | GrayPage = 1182 |hello Image = Dickdarm-Schema.svg | Caption = 1: [[Ascending colon]]<BR>2: [[Transverse colon]]<BR>3: [[Descending colon]]<BR>4: [[Sigmoid colon]]<BR>5: [[Rectum]]<BR>| Image2 = Gray1223.png | Caption2 = Front of abdomen, showing surface markings for liver, stomach, and great intestine. | Precursor = [[hindgut]] | System = | Artery = [[sigmoid arteries]] | Vein = | Nerve = [[superior mesenteric ganglia]], [[sacral nerve]] <ref>{{GeorgiaPhysiology|6/6ch2/s6ch2_30}}</ref> | Lymph = | MeshName = | MeshNumber = | DorlandsPre = c_47 | DorlandsSuf = 12249909 | }} The '''sigmoid colon''' ('''pelvic colon'''; '''sigmoid flexure''') forms a loop which averages about 40 cm. in length, and normally lies within the [[pelvis]], but on account of its freedom of movement it is liable to be displaced into the [[abdominal cavity]]. ==Path== It begins at the [[superior aperture]] of the [[lesser pelvis]], where it is continuous with the [[iliac colon]], and passes transversely across the front of the [[sacrum]] to the right side of the pelvis. It then curves on itself and turns toward the left to reach the middle line at the level of the third piece of the [[sacrum]], where it bends downward and ends in the [[rectum]]. According to [[Isaac Asimov]]'s book ''The Human Body,'' the name ''sigmoid'' means "[[S]]-shaped." ==Coverings== It is completely surrounded by [[peritoneum]] (and thus is NOT [[Retroperitoneal]]), which forms a [[mesentery]] ([[sigmoid mesocolon]]), which diminishes in length from the center toward the ends of the loop, where it disappears, so that the loop is fixed at its junctions with the [[iliac colon]] and rectum, but enjoys a considerable range of movement in its central portion. ==Innervation== [[Pelvic splanchnic nerves]] are the primary source for [[parasympathetic]] innervation. ==Relations== Behind the sigmoid colon are the [[external iliac vessels]], the left [[Piriformis]], and left [[sacral plexus]] of nerves. In front, it is separated from the [[Urinary bladder|bladder]] in the [[male]], and the [[uterus]] in the [[female]], by some coils of the [[small intestine]]. ==Additional images== <gallery> Image:illu_intestine.jpg|Intestines Image:Gray538.png|Sigmoid colon and rectum, showing distribution of branches of inferior mesenteric artery and their anastomoses. Image:Gray1076.png|Iliac colon, sigmoid or pelvic colon, and rectum seen from the front, after removal of pubic bones and bladder. <br> hi Image:WeiblichesBeckenMedian.gif|Sagittal section of the lower part of a female trunk, right segment. </gallery> ==References== <references/> ==External links== * {{eMedicineDictionary|Sigmoid+colon}} * {{SUNYAnatomyFigs|37|06|07}} - "The large intestine." * {{NormanAnatomy|sup&infmesentericart}} {{Gray's}} {{digestive-stub}} {{Digestive tract}} [[de:Colon sigmoideum]] [[dv:ސިގްމޮއިޑް ގޮހޮރު]] [[fr:Sigmoïde (anatomie)]] [[it:Sigma (anatomia)]] [[la:Colon sigmoideum]] [[pl:Esica]] [[pt:Sigmóide]] [[ru:Сигмовидная кишка]] [[sv:Colon sigmoideum]]