Lecture 3 Abdominal Viscera I PDF

Abdominal viscera I Gastrointestinal tract  Subdivisions: alimentary blood supply Foregut – Stomach → middle 2nd part duodenum Supplied: celiac trunk Midgut – Middle 2nd part duodenum → j(x) prox. 2/3 & distal 1/3 transverse colon Supplied: SMA, inf. pancre...

Abdominal viscera I Gastrointestinal tract  Subdivisions: alimentary blood supply Foregut – Stomach → middle 2nd part duodenum Supplied: celiac trunk Midgut – Middle 2nd part duodenum → j(x) prox. 2/3 & distal 1/3 transverse colon Supplied: SMA, inf. pancreaticoduodenal artery; jejunal & ileal branches, ileocolic artery: appendicular branch, ant. & post. Cecal branches, ileal branch, right colic artery & middle colic artery Hindgut – J(x) prox. 2/3 & distal 1/3 transverse colon → sup. 1/3 rectum Supplied: IMA, left colic artery, sigmoid branches & sup. rectal artery  Oesophagus Oesophagus – Muscular tubular structure: 25 – 30cm – Extends: J(x) with laryngopharynx, T4 – T5 opposite cricoid cartilage (level C6) → stomach – Displaced to right by (level T10) aortic arch which moves – Enters into the left of it Superior mediastinum – Post. mediastinum: between the trachea and oesophagus first right vertebral column then ant. to aorta – Ends: through diaphragm (T10) – ant. & left of aorta – Accompanied by: L & R vagus n Constrictions: oesophagus  Course: oesophagus Thoracic!!! (previous lecture) Pass – oesophageal hiatus in right crus of diaphragm (T10) – Phrenico-oesophageal ligament Extension: inf. diaphragmatic fascia Terminates: stomach → cardial orifice of stomach, left to midline (7th CC, T11) – oesophagogastric j(x) Encircled: oesophageal nerve plexus distally – Parasympathetic (vagus) & sympathetic (greater splanchnic) Blood supply & venous drainage – Oesophageal branches: left gastric a., inf. phrenic a. – Portal venous system Oesophageal varices  Stomach: surface anatomy Cardia orifice: – Deep to 6th costal cartilage, 2.5cm to the left of the midline (T11) Fundus: – Post. left 6th rib, MCL Pylorus: – On transpyloric plane, 2.5cm to the right of the midline – Vertebral height L1 / L2 Body: – Lies inferior of the above- mentioned plane  Cardiac notch Cardiac zone Fundus – 5th IC:space Cardio-oesophageal orifice Pylorus (Gatekeeper) Body Angular notch Gastric folds Pyloric antrum Gastric and fundic zones Pyloric zone  Relations: stomach Covered in peritoneum – Except: bl. vessels run along curvatures 2 layers: lesser omentum – surround stomach & leave greater curvature – greater omentum Anterior: – Diaphragm, left liver lobe & ant. abdominal wall Posterior – Omental bursa, pancreas  Relations: Stomach Bed of stomach – Sup. – inf.: left dome diaphragm, spleen, left kidney, splenic artery, pancreas & transverse mesocolon & colon Blood supply: stomach Celiac trunk Common hepatic artery – Gastroduodenal artery Anterior superior pancreaticoduodenal artery Right gastro-omental artery – Proper hepatic artery Right gastric artery Right hepatic artery – Cystic artery Left hepatic artery Blood supply: stomach Celiac trunk Splenic artery – Left gastro-omental artery – Short gastric artery – Posterior gastric Left gastric artery Venous drainage: stomach Right & left gastric veins – Portal vein Short gastric vein & left gastro-omental vein – Splenic vein Right gastro-omental vein – Sup. mesenteric vein Prepyloric vein – Right gastric vein Splenic + SMV = portal Pre-aortic lymph nodes Celiac nodes Afferent: organs (foregut), superior & inferior mesenteric nodes Efferents: cisterna chyli Superior mesenteric nodes Afferents: organs (midgut), inferior mesenteric nodes Efferents: celiac nodes Inferior mesenteric nodes Afferents: organs (hindgut) Efferents: superior mesenteric nodes Para-aortic lymph nodes Lateral aortic/Lumbar nodes Afferents: body wall, kidneys, suprarenal glands, testes or ovaries Lymphatic drainage: Stomach Gastric lymph nodes Afferents: sup. 2/3 of stomach Efferents: celiac lymph nodes Gastro-omental lymph nodes Afferents: ant. & post. surface of stomach Efferents: celiac lymph nodes Pancreaticosplenic lymph nodes Afferents: fundus, superior part of body of stomach Efferents: celiac lymph nodes Pyloric lymph nodes Afferents: right 2/3 of inferior 1/3 stomach Efferents: celiac lymph nodes Pancreaticoduodenal lymph nodes Afferents: left 1/3 of greater curvature Efferents: pyloric OR celiac lymph nodes Nerve supply: stomach Vagus nerve (CN X) Enters abdomen at T10 together with oesophagus Parasympathetic supply to GI tract as far as the left colic flexure Contributions to – Cardiac plexus – Oesophageal plexus – Aortic plexus – Celiac plexus Branches: – Oesophageal – Gastric – Pancreatic – Branches to gallbladder – Branches to intestine as far as the left colic flexure  Nerve supply: stomach Vagus trunks (PS) – Ant. vagal trunk (LVN) Lesser curvature Hepatic & duodenal branches Ant. gastric branches – Post. vagal trunk (RVN) Lesser curvature Ant. & post. Surfaces Celiac branch – celiac plexus Post. gastric branches Sympathetic supply: T6 – T9: greater splanchnic nerve Distributed: plexuses – gastric & gastro-omental a.  Small intestine Duodenum – Pyloric part of stomach - empties Jejunum Ileum – Ileocecal junction – cecum Primary site – absorption of nutrients Duodenum: surface anatomy Pylorus – Transpyloric line run through – L1: L2 – 1st part duodenum 2nd part – Run inferiorly left of R-MCL – Turns at L3 Duodenojejunal junction (left side) – Junction: L3, left of midline – Extend to sup. border L2 Duodenum 4 parts – Superior (first) Anterolateral – body L1 – Descending (second) Right sides: L1 – L3 – Horizontal (third) Cross L3 – Ascending (fourth) Left of L3 – rise superiorly – sup. border L2  Relations Superior part (1st part) – Ant: quadrate lobe liver, gall bladder & peritoneum – Post: portal vein, bile duct, gastroduodenal a. & IVC – Sup: neck gallbladder – Inf: neck pancreas Descending part (2nd part) – Ant: transverse colon – Post: R kidney, ureter, psoas major – Med: head pancreas, pancreatic duct, bile duct – Posteromedial: major & minor duodenal papillae (entrance – pancreatic ducts)  Relations Horizontal part – Ant: sup. mesenteric a. & mesentery small intestine – Post: IVC, aorta, R psoas major, R ureter & body L3 – Sup: head of pancreas, sup. mesenteric vessels Ascending part – Post: L psoas major, L margin aorta – Med: head pancreas – Sup: body pancreas – Suspensory ligament of duodenum (Lig. of Treitz) extend from right crus of diaphragm (duodenojejunal j(x)) Blood supply: Duodenum Celiac trunk Common hepatic artery Gastroduodenal artery Superior pancreaticoduodenal artery Inferior pancreaticoduodenal artery Superior mesenteric artery **Duodenum – 1st transition in blood supply of abdominal part of alimentary tract Venous drainage: duodenum Veins follow arteries – Drain → portal vein Drain directly/indirectly – Sup. mesenteric v. – Splenic v.  Nerve supply Vagus (CN X) & Greater & lesser splanchnic n. – Celiac & sup. mesenteric plexuses Periarterial plexuses – Pancreaticoduodenal arteries Lymphatic drainage: Duodenum Pancreaticoduodenal lymph nodes Afferents: anterior surface of duodenum Efferents: celiac lymph nodes Pyloric lymph nodes Afferents: anterior surface of duodenum Efferents: superior mesenteric lymph nodes Superior mesenteric lymph nodes Afferents: posterior surface of duodenum Efferents: celiac lymph nodes Jejunum & Ileum Jejunum (2/5) – Begin: duodenojejunal j(x) – Lie mostly: left, upper quadrant Ileum (3/5) – End: ileocecal j(x) – Lie mostly: right, lower quadrant – Terminal ileum – lie in pelvis: ascends to med. cecum Jejunum & Ileum Mesentery of small intestine – Fan-shaped fold: peritoneum – Attaches J & I → post. abdominal wall – Root of mesentery Oblique, inferior & to right Extend: duodenojejunal j(x), left L2 → ileocecal j(x) & right sacroiliac joint Crosses: Ascending & horizontal parts of duodenum Abdominal aortal IVC Right ureter Right psoas major Right gonadal vessels Blood supply: J & I Superior mesenteric artery Runs in folds: mesentery – 15: 18 branches Unite – form loops/arches – arterial arcades Give rise to straight arteries – vasa recta Neurovascular supply: J & I Venous – Sup. mesenteric vein Ant. & right – SMA in root of mesentery Unites: splenic vein → portal vein (post. neck of pancreas) Innervation – Sympathetic T8 – T12 → through sympathetic trunks & splanchnic nerves → reach sup. mesenteric plexus – Parasympathetic Post. vagal trunks  Distinguishing characteristics of I&J Characteristics Jejunum Ileum Colour Deeper red Paler pink Caliber 2 – 4cm 2 – 3cm Wall Thick and heavy Thin and light Vascularity Greater Less Vasa recta Long Short Arcades A few large loops Many short loops Fat in mesentery Less More Circular folds Large, tall & closely packed Low and sparse, absent in the distal end Lymphoid nodules Few Many  Colour Caliber Wall Vascularity Vasa recta Arcades Fat in mesentery Circular folds Lymphoid nodules  Meckel’s diverticulum Congenital abnormality (1 – 2%) – Remnant of proximal part of embryonic yolk stalk – Finger-like pouch – Inflamed & pain  Large intestine: Colon Consists: – Cecum, appendix, ascending, transverse, descending & sigmoid colon, [rectum & anal canal] – Omental appendices Small, fatty omentum-like projections – 3 teniae coli (thickened bands – smooth m.) 1: Mesocolic: transverse & sigmoid mesocolons attach 2: Omental: omental appendices attach 3: Free: nothing attached – Haustra: sacculations of wall of colon between teniae  Cecum & appendix Cecum – 1st part of large intestine: continuous ascending colon – Intestinal pouch Lies in right iliac fossa, inf. to j(x) of terminal ileum & cecum – Ileal orifice: Ileal papillae – folds meet lat – frenula of ileocecal valve Appendix – intestinal diverticulum – Arise: posteromedial aspect cecum inf. to ileocecal j(x) – Mesoappendix: short ∆ mesentery Attached – cecum & prox. part of appendix – Position: variable  Appendix variations Retrocecal Retrocolic Subcecal Pelvic Retro-ileal Pre-ileal **McBurney’s point Neurovascular supply: C & A Arterial – Cecum: Ileocolic artery (TB: SMA) – Appendix: Appendicular artery (B: ileocolic) Venous – Ileocolic vein → SMV Lymphatic drainage – Nodes in mesoappendix – Ileocolic lymph nodes (ileocolic artery) – Sup. mesenteric nodes (efferent vs.) Innervation – Sup. Mesenteric plexus Sympathetic: lower thoracic Parasympathetic: vagus nerves  Ascending colon Lie in relation – Right iliac fossa, iliac crest, quadratus lumborum, transversus abdominis & lower pole of right kidney – Ant: greater omentum Course – Sup. on right side abdominal cavity (from cecum) to right lobe liver – Turns – left: right colic flexure Peritoneum: ant. & sides Blood supply: AC & RCF Superior mesenteric artery Ileocolic artery Right colic artery 1st series of anastomotic Middle colic artery arcades Left colic artery & sigmoid arteries Marginal artery  Neurovascular supply: AC & RCF Venous – Ileocolic & right colic veins (SMV) Lymphatics – Epicolic & paracolic nodes → ileocolic & intermediate right colic nodes → sup. mesenteric nodes Innervation – Superior mesenteric nerve plexus  Transverse colon Lie in relation: – Ant: right lobe liver, gall bladder, quadrate lobe liver, stomach & greater omentum – Post: right kidney, 2nd part duodenum, head & body of pancreas Course: – Across abdomen: right colic flexure → left colic flexure (LCF) – LCF – ant. to inf. left kidney & suspended from diaphragm - phrenicocolic ligament Mesentery: transverse mesocolon – Root of transverse mesocolon lies inf. to border of pancreas & continuous – parietal peritoneum post. Blood supply: TC Superior mesenteric artery Middle colic artery Right colic artery **Via anastomosis (Marginal artery) Left colic artery  Neurovascular supply: TC Venous – Superior mesenteric vein Lymphatics – Middle colic nodes → sup. mesenteric nodes Innervation – Sup. Mesenteric plexus via Periarterial plexuses: R & middle colic a. Transmit: sympathetic, parasym., & visceral afferent  Descending colon Relations: – Left iliac crest and left iliac fossa Course: – Left colic flexure → sigmoid colon (continuous) – Descends: past lat. border of left kidney Peritoneum: – Ant. & lat. – bind to post. abdominal wall  Sigmoid colon Course – Extend: iliac fossa (left) → S3 segment – Termination of teniae coli: indicate rectosigmoid junction Mesentery – Root of sigmoid mesocolon Inverted V-shape attachment Extends: – Med. & sup. along external iliac vessels – Med. & inf. from bifurcation to common iliac vessels – To ant. aspect of sacrum Blood supply: DC & SC Inferior mesenteric artery Left colic artery Sigmoid arteries Ascending & descending Middle colic artery Marginal artery Superior mesenteric artery **LCF – 2nd transition in blood supply of abdominal part of alimentary tract  Neurovascular supply: DC & SC Venous – Inferior mesenteric vein → splenic → portal v Lymphatics – Epicolic & paracolic nodes → intermediate colic nodes → inf. mesenteric nodes – Left colic flexure: may – sup. mesenteric nodes Innervation – Sympathetic: Lumbar part of sympathetic trunk via lumbar splanchnic nerves, the sup. mesenteric plexus & periarterial plexuses – Parasympathetic: Pelvic splanchnic nerves via inf. hypogastric plexus