Mesentery, jejunum, ileum & superior mesenteric artery -PDF Lecture Notes -Dr.N.Mugunthan
This document discusses the anatomy of the mesentery and related structures. It describes the mesentery as the peritoneal fold that suspends the jejunum and ileum from the posterior abdominal wall. It provides blood supply and innervation to the intestines. The root of the mesentery extends from L2 to the right sacroiliac joint and crosses several structures. The superior mesenteric artery supplies the midgut and branches to form the jejunal and ileal arteries. Meckel's diverticulum is described as a remnant of the vitelline duct that can cause complications like perforation or intestinal obstruction.
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Mesentery, jejunum, ileum & superior mesenteric artery -PDF Lecture Notes -Dr.N.Mugunthan
- 1. Dr. N.Mugunthan. MS,DNB, MNAMS, PhD., Professor MGMC & RI
- 2. OBJECTIVES Mesentery Jejunum & ileum Superiormesenteric artery Applied anatomy © Dr.N.Mugunthan ©Dr.N.Mugunthan
- 3. MESENTERY Peritoneal fold Broad fan shaped Suspends jejunum and ileum from posterior abdominal wall Support Conveys nutrition & innervates the gut Consists of 2 layers - from greater sac © Dr.N.Mugunthan ©Dr.N.Mugunthan
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- 5. BORDERS OF MESENTERY •Vertebral border or attached border or root • Intestinal or free border © Dr.N.Mugunthan ©Dr.N.Mugunthan
- 6. FREE BORDER • Frilledborder • 20 feet long • Separates to enclose jejunum & ileum © Dr.N.Mugunthan ©Dr.N.Mugunthan
- 7. ROOT OF THEMESENTERY • Attached border • 6 inches length Extent: • From the left side of L2 at duodenojejunal flexure to the right sacro-iliac joint at the ileo-caecal junction © Dr.N.Mugunthan ©Dr.N.Mugunthan
- 8. STRUCTURES CROSSED BYTHE ROOT • 3rd part of duodenum • Abdominal aorta • IVC • Rt. Gonadal vessels • Rt.Ureter and psoas major • Rt.Genito femoral nerve • Rt.Sacro-iliac joint © Dr.N.Mugunthan ©Dr.N.Mugunthan
- 9. RELATIONS OF MESENTERY •Rt.Surface -covers front and sides of ascending colon • Rt.paracolic gutter • Lt.Surface - covers front and sides of descending colon • Lt.para colic gutter • Above-pancreas • Below-sigmoid colon © Dr.N.Mugunthan ©Dr.N.Mugunthan
- 10. CONTENTS • Jejunum andileum • Superior mesenteric vessels • Autonomic nerves • Lymphatics -lacteals and mesenteric nodes • Loose areolar tissue • Fat © Dr.N.Mugunthan ©Dr.N.Mugunthan
- 11. APPLIED ANATOMY • Superiormesenteric artery syndrome • Mesenteric adenitis • Mesenteric cyst © Dr.N.Mugunthan ©Dr.N.Mugunthan
- 12. JEJUNUM & ILEUM Definition: •Mobile part of small intestine • Suspended from the posterior abdominal wall by mesentery © Dr.N.Mugunthan ©Dr.N.Mugunthan
- 13. Extension: • Extends fromthe duodeno- jejunal flexure to the ileo- caecal junction • Length - 6 meters or 20 feet • Jejunum -8 feet • Ileum -12 feet 2/5th of small intestine may be removed surgically without any physiological disturbance JEJUNUM & ILEUM cont… © Dr.N.Mugunthan ©Dr.N.Mugunthan
- 14. DIFFERENCES BETWEEN JEJUNUM& ILEUM S.No Jejunum Ileum 1. Location Upper part of the peritoneal cavity Lower part of the peritoneal cavity 2. General appearance Wider , thicker walled and reddish Narrower, thin walled and paler 3. Attachment of mesentery To the posterior abdominal wall above and to the left of the aorta Below and to the right of the aorta. 4. Arterial arcades Only one or two arcades / vasa recta is long Three or four or even more arcades/vasa recta is short 5. Translucent windows Translucent windows are clearly seen (less fat) Translucent windows are not clearly seen (more fat) 6. Interior a. Plicae circularis – larger & more numerous b. Villi-longer and more numerous. c. Payer’s patches -absent A.Plicae circularis – smaller & less numerous B. Shorter and less numerous C. Payer’s patches -present© Dr.N.Mugunthan ©Dr.N.Mugunthan
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- 16. Jejunal branches Ilealbranches Few arterial arcades & long vasa recta More arterial arcades & short vasa recta © Dr.N.Mugunthan ©Dr.N.Mugunthan
- 17. STRUCTURE OF JEJUNUM& ILEUM 4 coats (from without inwards) 1. Serous coat 2. Muscular coat 3. Submucous coat 4. Mucous coat a. muscularis mucosa b. lamina propria c. epithelium © Dr.N.Mugunthan ©Dr.N.Mugunthan
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- 19. SUPERIOR MESENTERIC ARTERY •Artery of mid gut Origin: • From abdominal aorta @ L1 Course & relations: • Downwards, forwards and to the right infront of • Uncinate process of pancreas 3rd part of duodenum, • IVC • Rt.Psoas • Rt.Ureter • Runs along the root of mesentery to rt.Iliac fossa. Termination: • Ends by joining with its ileocolic branch. © Dr.N.Mugunthan ©Dr.N.Mugunthan
- 20. Branches: • Inferior pancreatico- duodenalartery • Jejunal branches (5-6) • Ileal branches (6-8) • Ileo-colic artery o Ant.caecal, post.caecal & appendicular artery • Rt.colic artery. • Middle colic artery. SUPERIOR MESENTERIC ARTERY cont… © Dr.N.Mugunthan ©Dr.N.Mugunthan
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- 22. Summary of SMA: •SMA –artery of mid gut • Supplies entire small gut except the proximal part of duodenum upto the ampulla of vater • Supplies large gut upto the junction of rt.2/3rd and left 1/3rd of the transverse colon • Also supplies lower part of head of the pancreas. SUPERIOR MESENTERIC ARTERY cont… © Dr.N.Mugunthan ©Dr.N.Mugunthan
- 23. SUPERIOR MESENTERIC VEIN Drains the small intestine, caecum,ascending and transverse colon Formation: • By union of tributaries from terminal ileum, caecum & appendix Course & relations: • Ascends to the right of SMA • Passes anterior to rt.ureter, IVC, 3rd duodenum, uncinate process of pancreas Termination: • Joins with splenic vein to form the portal vein @ behind the neck of pancreas © Dr.N.Mugunthan ©Dr.N.Mugunthan
- 24. Tributaries of SMV: •Jejunal veins • Ileal veins • Ileocolic vein • Rt.Colic vein • Middle colic vein • Rt.Gastro-epiploic vein • Pancreatico-duodenal veins SUPERIOR MESENTERIC VEIN cont… © Dr.N.Mugunthan ©Dr.N.Mugunthan
- 25. NERVE SUPPLY • Extrinsiccomponent – sympathetic & parasympathetic • Intrinsic component – myenteric plexus (Auerbach’s plexus) & submucous plexus(Meissner’s plexus) © Dr.N.Mugunthan ©Dr.N.Mugunthan
- 26. LYMPHATIC DRAINAGE Lacteals(intestinal lymphatics) Mesenteric lymph nodes © Dr.N.Mugunthan ©Dr.N.Mugunthan
- 27. APPLIED ANATOMY Meckel’sdiverticulum Intestinal obstruction Enteritis Paralytic ileus Tuberculosis Enteric fever (typhoid) Acute mesenteric infarction- abdominal angina Polyps-peutz-jeghers Carcinoid/apudomas Intussusception © Dr.N.Mugunthan ©Dr.N.Mugunthan
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- 29. MECKELS DIVERTICULUM Definition: • remnantof the proximal part of vitello-intestinal duct • blind pouch arises from the anti-mesenteric border of ileum • 2 feet proximal to ileocaecal junction • 2 inches long • 2 % of subjects it is present © Dr.N.Mugunthan ©Dr.N.Mugunthan
- 30. MECKELS DIVERTICULUM cont… 1.Peptic ulcer in the mucous membrane lead to perforation 2. Diverticulitis resembling acute appendicitis 3. Intestinal obstruction (loop of small intestine may encircle the fibrous band) Invaginated meckel’s diverticulum with intussusception ( tip of diverticulum has ectopic pancreatic tissue) © Dr.N.Mugunthan ©Dr.N.Mugunthan
- 31. SUMMARY Mesentery Root of mesentery& structures crossed by it Superior mesenteric artery Branches Applied anatomy Meckel’s diverticulum © Dr.N.Mugunthan ©Dr.N.Mugunthan
- 32. Thank u 4Listening