2The large intestine (or colon) Dr. Maria ZahiriThe large intestine (or colon)the last part of the digestive systemAbsorb water, sodium and some fat soluble vitamins.The large intestine consists of :the cecum, appendix, colon, rectum, and anal canal.is about 4.9 feet (1.5 m) long
4Characteristics of large intestine Dr. Maria ZahiriCharacteristics of large intestineTaeniae coli: three bands of smooth muscleHaustra : bulges caused by contraction of taeniae coliEpiploic appendages (omental appendices ):are small pouches of the peritoneum filled with fat and situated along the colon.their function is unknown.
7Dr. Maria ZahiriCaecumPosition: Lie in the right iliac fossa below the ileocaecal valve. Is a intraperitoneal organ (?) Posteriorly lies the retrocaecal recess which frequently contains the vermiform appendix. Size: Average 6-7 cm
8Blood supply *Ileocolic artery Vascular supply for caecum Dr. Maria ZahiriBlood supplyVascular supply for caecum*Ileocolic arterySuperior branchInferiorbranchAscending (colic) arteryAnterior caecal arteryPosterior caecal arteryAppendicular arteryIleal artery
9Superior branch Inferior branch Appendicular artery Ileal artery Dr. Maria ZahiriIleal arterySuperior branchInferior branchAppendicular artery
15The vermiform appendix Dr. Maria ZahiriThe vermiform appendixis a narrow, vermian tubearises from the posteromedial caecal wallit varies from 5 to 20 cm in length, 2 cm below the end of the ileum.
16The vermiform appendix Dr. Maria ZahiriThe vermiform appendixIt may occupy one of several positions: the commonest positions Retrocaecal (12 o’clock), retrocolic , pelvic or descending (4 o’clock) Other positions are occasionally seen especially when there is a long appendix mesentery allowing greater mobilit: subcaecal(6 o’clock) ; preilial(2 o’clock) ; postileal(2 o’clock) .
18Dr. Maria ZahiriThe three taeniae coli on the ascending colon and caecum converge on the base of the appendix, and merge into its longitudinal muscle. The anterior caecal taenia is usually distinct and can be traced to the appendix. It is connected by a short mesoappendix to the lower part of the ileal mesentery.
19Dr. Maria ZahiriThe lumen of the appendix is small and opens into the caecum by an orifice lying below and slightly posterior to the ileocaecal opening. The orifice is sometimes guarded by a semi lunar mucosal fold forming a valve. The appendix usually contains numerous patches of lymphoid tissue although these tend to decrease in size from early adulthood.
20VASCULAR SUPPLY Ileocolic artery Inferior branch Appendicular artery Dr. Maria ZahiriVASCULAR SUPPLYIleocolic arteryInferior branchAppendicular arteryaccessory arteries are common
21Dr. Maria Zahiri one or more appendicular veins posterior caecal ileocolic veinSuperior mesenteric vein
22Dr. Maria ZahiriLymphatic vesselsare numerous but all end in the inferior and superior nodes of the ileocolic chain.
23Dr. Maria ZahiriInnervationsympathetic and parasympathetic nerves from the superior mesenteric plexus.
24Dr. Maria Zahiricolonthe colon consists of four sections: the ascending colon, the transverse colon, the descending colon, and the sigmoid colon
25Ascending colon narrower than the caecum- 15cm Dr. Maria Zahirinarrower than the caecum- 15cmIt ascends to the inferior surface of the right lobe of the liver, on which it makes a shallow depression, and then turns abruptly forwards and to the left, at the hepatic flexure.It is a retroperitonealTold fascia
27TRANSVERS COLON The transverse colon is 50 cm long Dr. Maria ZahiriTRANSVERS COLONThe transverse colon is 50 cm longextends from the hepatic flexure in the right lumbar region across into the splenic flexure.The transverse colon is suspended from the anterior border of the body of the pancreas by the transverse mesocolon.
29Dr. Maria ZahiriSPLENIC FLEXUREforms the junction of the transverse and descending colonlies in the left hypochondriac region anteroinferior to the lower part of the spleenThe left kidney lies behind to it
30It lies more superiorly and posteriorly than the right hepatic flexure Dr. Maria ZahiriIt lies more superiorly and posteriorly than the right hepatic flexureis attached to the diaphragm at the level of the tenth and eleventh ribs by the phrenicocolic ligament which lies below the anterolateral pole of the spleen.
31DESCENDING COLONDr. Maria Zahiri25 cmIt descends through the left hypochondriac and lumbar regionscurves inferomedially to become the sigmoid colon at the inlet of the lesser pelvis.It is a retroperitoneal structure covered anteriorly and on both sides by peritoneum.
32SIGMOID COLON begins at the pelvic inlet and ends at the rectum(S3) Dr. Maria Zahiribegins at the pelvic inlet and ends at the rectum(S3)It is completely invested in peritoneum and is attached to the posterior pelvic wall and lower posterior abdominal walls by the fan-shaped mesosigmoid.The root of the sigmoid mesocolon has an inverted 'V‘ shape.The position and shape of the sigmoid colon vary greatly
33Dr. Maria ZahiriLeft paracolic gutterLeft ureter
34Superior mesenteric a. Superior Middle colic a. Mesenteric v. Dr. Maria ZahiriSuperiorMesenteric v.Middle colic a.Inf. pancresticodudenal a.Superiormesenteric a.Right colic a.Jejunal and ileal a.Ileocolic a.Appendicular a.
35Inferior mesenteric a. Inferior mesenteric v. Left colic a. Sigmoid a. Dr. Maria ZahiriInferior mesenteric a.Left colic a.Sigmoid a.Superior rectal a.
38The Sudeck's point (or Sudeck's critical point): Dr. Maria ZahiriThe Sudeck's point (or Sudeck's critical point):refers to a specific location in the arterial supply of the rectosigmoid junction, namely the origin of the last sigmoid arterial branch from the inferior mesenteric artery (IMA) . This arterial branch usually forms an anstomosis with a branch of the superior rectal artery. The anastomosis is small and often only singular.
39The "critical point" of Sudeck is marked with an "X." Dr. Maria ZahiriThe "critical point" of Sudeck is marked with an "X."
40Rectum Rectum continuous with the sigmoid colon(S3) Dr. Maria ZahiriRectumRectum continuous with the sigmoid colon(S3)To upper end of the anal canal.Flexure:the sacral flexure & the perineal flexurethree lateral curves :upper is convex to the right, the middle (the most prominent) bulges to the left, and the lower is convex to the rightBoth ends of the rectum are in the median plane
42: 2/3anterior and 1/3lateral covered by peritoneum. Dr. Maria Zahiri: 2/3anterior and 1/3lateral covered by peritoneum.the rectovesical pouch :The peritoneum is reflected superiorly onto the urinary bladder in malesrecto-uterine pouch (pouch of Douglas):onto the posterior vaginal wall in females
45ARTERIES 1.superior rectal artery: upper third Dr. Maria Zahiri1.superior rectal artery: upper third2.middle rectal artery: middle third (from Int. Iliac)3.inferior rectal artery: distal third ( from Int. pudendal)
46veins 1.internal part: below the rectal and anal epithelium Dr. Maria Zahiriveins1.internal part: below the rectal and anal epithelium2.external part: outside the muscular wall
47veins External plexus: 1.inferior portion of the external plexus : Dr. Maria ZahiriExternal plexus:1.inferior portion of the external plexus :is drained by the inferior rectal vein into the internal pudendal vein2.middle portion :by a middle rectal vein into the internal iliac vein,3.superior part :By a superior rectal vein, which is the start of the inferior mesenteric vein. Communication between portal and systemic venous systems is thus established in the rectal plexus.