1. SMALL & LARGE INTESTINE
Dr. Ahmed Fathalla Ibrahim

2. ABDOMINAL VISCERA FOR EACH PART YOU MUST KNOW: SURFACE ANATOMY
RELATIONS
PERITONEAL COVERING
BLOOD SUPPLY
NERVE SUPPLY
LYMPHATIC DRAINAGE
SUPPORT (IN SOME PARTS)

3. SMALL INTESTINE DUODENUM: fixed part
JEJUNUM & ILEUM: movable part (with mesentery)

4. JEJUNUM & ILEUM Length: 6 meters (20 feet)
Beginning: duodenojejunal flexure
Termination: ileocecal junction
Embryological origin: midgut
Peritoneal fold: mesentery of small intestine
Arterial supply: jejunal & ileal branches of superior mesenteric
Lymphatic drainage: superior mesenteric lymph nodes
Nerve supply: superior mesenteric plexus: sympathetic & parasympathetic (vagus)

13. MESENTERY OF SMALL INTESTINE
Extent: from duodenojejunal flexure to ileocecal junction
Formation: formed of 2 layers
Free border (6 meters long): encloses jejunum & ileum
Root (6 inches long, J-shaped): crosses superficial to the following structures:
Third part of duodenum
Abdominal aorta
Inferior vena cava
Right psoas major
Right ureter

14. MESENTERY OF SMALL INTESTINE
Shape: Fan-shaped with undulations
Content of root: superior mesenteric vessels
Contents (structures between its 2 layers):
Jejunal vessels: form few arcades
Ileal vessels: form many arcades
Mesenteric lymph nodes
Autonomic nerve fibers
Mesenteric fat

15. MESENTERY OF SMALL INTESTINE

16. JEJUNUM Length: shorter (proximal 2/5) Diameter: wider
Wall: thicker (more numerous plicae circulares: circular folds of mucosa)
Appearance: more red in color (more vascular)
Vessels: less arcades, long terminal branches
Mesenteric fat: small amount near intestinal border
Aggregations of lymphoid tissue: few

17. ILEUM Length: longer (distal 3/5) Diameter: narrower
Wall: thinner (less numerous plicae circulares: circular folds of mucosa)
Appearance: light red in color (less vascular)
Vessels: more arcades, short terminal branches
Mesenteric fat: large amount near intestinal border
Aggregations of lymphoid tissue: numerous (Peyer’s patches)

18. LARGE INTESTINE PARTS: Cecum Appendix Ascending colon Transverse colon
Descending colon
Sigmoid (pelvic) colon
Rectum
Anal canal
N.B.: Parts of large intestine in abdomen: from 1 to 5

20. LARGE INTESTINE CHARACTERISTICS:
Teniae coli: 3 longitudinal muscle bands
Sacculations (haustrations): teniae coli are shorter than large intestine
Appendices epiploicae: short peritoneal fold filled with fat
N.B.: characteristics are present in all large intestine EXCEPT: in rectum & anal canal

21. LARGE INTESTINE Embryological origin:
From midgut: cecum, appendix, ascending colon, right 2/3 of transverse colon
From hindgut: left 1/3 of transverse colon, descending & sigmoid colon, rectum, upper half of anal canal
Peritoneal fold:
Appendix, transverse & sigmoid colon: have mesentery
Cecum: completely covered by peritoneum, but has no mesentery
Ascending & descending colon: covered anteriorly & on the sides
Rectum & anal canal: discussed later

22. LARGE INTESTINE Arterial supply:
Midgut: colic branches of superior mesenteric
Hindgut: inferior mesenteric
Lymphatic drainage:
Midgut: superior mesenteric lymph nodes
Hindgut: inferior mesenteric lymph nodes
Nerve supply:
Superior mesenteric plexus: sympathetic & parasympathetic (vagus)
Inferior mesenteric plexus: sympathetic & parasympathetic (pelvic splanchnic nerves)

23. LARGE INTESTINE SURFACE ANATOMY

24. APPENDIX
Surface anatomy: the base of appendix is marked by Mc’Burney’s point: A point at the junction of lateral 1/3 & medial 2/3 of a line traced from right anterior superior iliac spine to umbilicus
Opening: at posteromedial aspect of cecum, 1 inch below ileo-cecal junction

25. APPENDIX Positions: (from most to least common)
Retrocecal: most common position
Pelvic
Subcecal
Preilieal
Postileal

26. CECUM, ASCENDING & DESCENDING COLON
ANTERIOR RELATIONS:
Coils of small intestine
Greater omentum
Anterior abdominal wall

27. 1 2
Iliac crest 5 4 3 6
1: Iliohypogastric nerve; 2: Ilioinguinal nerve; 3: lateral cutaneous nerve of thigh
4: Femoral nerve; 5: Genitofemoral nerve; 6: Obturator nerve
P.M.= psoas major; Q.L.=quadratus lumborum; I.=iliacus;
T.A.= transversus abdominis

28. 1 2 5 3 6 4
1: Iliohypogastric nerve; 2: Ilioinguinal nerve; 3: lateral cutaneous nerve of thigh
4: Femoral nerve; 5: Genitofemoral nerve; 6: Obturator nerve
P.M.= psoas major; Q.L.=quadratus lumborum; I.=iliacus;
T.A.= transversus abdominis

29. CECUM, ASCENDING & DESCENDING COLON
POSTERIOR RELATIONS:
Cecum: psoas major, genitofemoral nerve, iliacus, lateral cutaneous nerve of thigh, femoral nerve
Ascending colon: iliacus, lateral cutaneous nerve of thigh, quadratus lumborum, ilioinguial nerve, iliohypogastric nerve, iliac crest, origin of transversus abdominis from lumbar fascia
Descending colon: relations of cecum + relations of ascending colon + left kidney

30. RELATIONS OF TRANSVERSE COLON

31. RELATIONS OF TRANSVERSE COLON
ANTERIOR: greater omentum, anterior abdominal wall
POSTERIOR: 2nd part of duodenum, head of pancreas, coils of small intestine
SUPERIOR: liver, gall bladder, stomach
INFERIOR: coils of small intestine