Week 7 Dissection PDF

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Summary

Red words of dissection week 7...

Description

Greater omentum ● Attaches to the greater curvature of the stomach, then descends inferiorly and then back up to attach to transverse mesocolon ● Acts as a blanket over the abdominal organs ● Protects the visceral peritoneum from attaching to parietal ● Has immune function, contains lymphatic vessels Lesser omentum ● Attached to lesser curvature of the stomach and liver ● Two ligaments on either side, hepatogastric and hepatoduodenal ● Only opening is epiploic foramen Gastro-epiploic vessels ● Right gastro-epiploic artery ○ One of the two terminal branches of gastroduodenal artery ○ Arises between the superior part of the duodenum and head of the pancreas ○ Has branches that travel to the greater omentum (omental branches) and stomach (gastric branches) ● Left gastro-epiploic artery ○ Arises from splenic artery, just before the hilum of the spleen ○ Travels through the gastrosplenic ligament ○ Has branches that travel to the greater omentum (omental branches) and stomach (gastric branches) ○ In about half of the population, the right and left gastroepiploic arteries anastomose ● Right gastro-epiploic vein ○ Drains into the superior mesenteric vein ● Left gastro-epiploic vein ○ Drains into the splenic vein Greater curvature ● Starts from the cardiac notch of the stomach ● Runs to the pylorus Omental bursa ● Bordered by the greater and lesser omentum, pancreas (posteriorly), left kidney ● Open to the greater sac via epiploic foramen Pancreas ● Exocrine and endocrine gland ● 4 parts: Head, neck, body and tail ● Head located in the C-shape of the duodenum ● Behind neck: SMA and SMV ● Behind body: aorta, IVC and left kindey/suprarenal gland ● Tail is intraperitoneal, closely related to the hilum of spleen

Splenic artery

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Origin: celiac trunk Runs on the superior border of the pancreas Three pancreatic branches ○ Dorsal, inferior and great pancreatic branches ○ Supply most of the body and tail of the pancreas Short gastric branches ○ Run along the upper parts of the greater curvature and gastrosplenic ligament ○ Supply fundus and cardiac orifice ○ Anastamose with branches of the left gastroepiploic arteries Another branch is the left gastroepiploic artery

Epiploic foramen ● Allows communication between the greater and lesser sac IVC ● ●

In close contact with the liver Drains into the right atrium

Portal triad ● Consists of portal vein, hepatic artery proper and bile duct Portal vein ● Formed by convergence of superior mesenteric vein and splenic vein (inferior mesenteric vein drains here) ● Takes blood away from GIT to be processed in the liver ● Immediately before entering the liver it divides into right and left branches ○ These branches further divide into hepatic venules which run along liver lobules Hepatic artery ● Large branch of common hepatic artery ● Branches: ○ Right gastric artery, left and right hepatic arteries ○ Right gastric arteries runs along the lesser curvature and ends about midway between lesser curvature by anastomosing with the left gastric artery Common bile duct ● Formed by the convergence of common hepatic duct (from right and left lobes of liver) and cystic duct (from gallbladder) ● Distal end, joins with pancreatic duct to form ampulla of vater

Diaphragm ● Primary muscle of inspiration ● Innervation: phrenic nerve (C3-5)

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Blood supply: intercostal arteries, superior and inferior phrenic arteries Three hiatus I 8 10 EGGS AT 12 ○ Caval foramen (IVC) → T8 ○ Esophagus, vagus nerve → T10 ○ Aorta, azygos vein, thoracic duct → T12

Right lobe of the liver ● Largest lobe of the liver

Bare area ● Liver is in direct contact with the diaphragm ● Groove for IVC

Coronary ligaments ● Attaches Superior surface of liver to diaphragm ● Demarcates the bare area ● Has anterior and posterior folds ○ Form to form triangular ligaments on left and right side of the liver Caudate lobe ● Located between fissure for ligamentum venosum and IVC ● Located posteriorly Attachments of the lesser omentum ● Hepatoduodenal ligament (separates the caudate and quadrate lobes) ● Hepatogastric ligament Impressions on the liver ● Suprarenal ● Renal ● Colic ● Duodenal ● Gastric ● All but the gastric are on the right lobe Cystic duct ● Allows emptying of gallbladder content OR storage of excess bile coming from hepatic ducts Common hepatic duct ● Forms by convergence of right and left hepatic ducts ● Joins with cystic duct to form common bile duct

Mesentery of the small intestine ● Attached to the jejunum and ileum ● Begins: duodenojejunal junction, left of L2 vertebrae ● Ends: ileocaecal junction, right sacroiliac joint ● Allows passage of arteries, veins and nerves needed for these structures Jejunum and ileum ● Transition from jejunum to ileum is not macroscopically visible and can only be identified microscopically ● Jejunum is found in the upper left quadrant ● Ileum is found in the lower right quadrant ● Supplied by jejunal and ileal branches of SMA ● Jejunum has longer vasa recta and fewer, large loop arcade ● Ileum has shorter vasa recta and more, short loop arcades Root of the mesentery ● L2 to right sacroiliac joint Parts of the duodenum ● 1st part (superior): ○ Only intraperitoneal part ○ Proximally it is dilated → duodenal bulb ● 2nd part (descending): ○ Starts at superior duodenal flexure and ends at inferior duodenal flexure ○ Ampulla of vater drains here ● 3rd part (horizontal): ○ Runs anteriorly of aorta and IVC ● 4th part (ascending) ○ Attached to the posterior abdominal wall through the suspensory ligament of duodenum (ligament of treitz) ○ Joins jejunum at duodenojejunal flexure ● Blood supply: ○ Superior (branch of gastroduodenal) and inferior (branch of SMA) pancreaticoduodenal arteries

Duodeno-jejunal flexure ● Joins duodenum and jejunum Ileo-caecal valve ● Sphincter muscle valve, separating the ileum and cecum ● Prevents backflow of colonic contents into the ileum

Stomach ● Cardia ● Fundus

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Body Pyloric part

Pylorus ● Two parts ○ Pyloric antrum - connected to the stomach ○ Pyloric canal - connected to the duodenum Cardiac notch ● Groove formed between oesophagus and fundus ● Greater curvature begins here Left gastric artery ● Branch of celiac trunk ● Supplies the superior half of the lesser curvature of the stomach ● Gives off esophageal branches ● Supplies body and fundus of the stomach as well as distal parts of the esophagus Esophageal branch of left gastric artery ● 1-3 branches ● Pass through the esophageal hiatus of the diaphragm ● Supplies distal esophagus ● Posterior branches anastomose with right gastric artery Right gastric artery ● Branch of the proper hepatic artery ● Runs along the lesser curvature and ends about midway between lesser curvature by anastomosing with the left gastric artery Aorta Crura of diaphragm ● Tendinous bands that attach the diaphragm to the vertebrae ● Right and left crura ● Attach to L1-L3 Caval foramen ● Level T8 ● IVC and branches of phrenic nerve pass through here Left phrenic artery ● C3-C5 ● Passes anterior to the anterior scalene, through the thoracic aperture, anterior to the root of the lung, lateral to the pericardium ● Supplies the left hemisphere of diaphragm

Suprarenal gland ● Sits on top of the kidneys ● Asymmetrical structures: right one is on top of the kidney while left one sits more medially ● Together with kidney sit in gerota’s fascia Upper pole of the left kidney ● Left suprarenal artery ● Inferior and middle suprarenal arteries ● Branches of the inferior phrenic artery (branch of thoracic aorta) Spleen ● Wrapped in fibroelastic capsule that allows significant expansion ● Located in the left upper quadrant ● Impressions: ○ Colic: splenic flexure ○ Gastric ○ Renal ○ Diaphragm: 9-11 ribs ● Gastrosplenic ligament ○ Connects the hilum with the greater curvature of the stomach ○ Contains short gastric and left gastro-epiploic vessels ● Phrenicocolic ligament ○ From splenic flexure to diaphragm, posterior to the spleen ○ Serves to support the spleen Lienorenal ligament ● AKA splenorenal ligament ● Connects the hilum of the spleen with the left kidney ● Contains the splenic artery and vein and tail of pancreas

Short gastric artery ● 5-7 seven arteries that are branches of the splenic artery ● Supply the fundus of the stomach Gastrosplenic ligament ● Connects the hilum of spleen with the greater curvature of the stomach ● Contains short gastric and left gastro-epiploic vessels Gastroduodenal artery ● Branch of the common hepatic artery ● Has two branches ○ Superior pancreaticoduodenal artery ○ Right gastro-epiploic artery

Superior pancreaticoduodenal artery ● Anterior and posterior ● Supplies the head of the pancreas and duodenum Inferior mesenteric vein ● Continuation of superior anorectal vein ● Tributaries: sigmoid and left colic veins ● Drainage: splenic vein (which together with SMV forms portal vein)

Superior mesenteric vein ● Tributaries: Ileal veins, ileocolic veins, right and middle colic veins, pancreatic, right gastro-epiploic veins Middle colic artery ● First branch of SMA ● Travels through the transverse mesocolon to supply the transverse colon ● Right and left branch ○ Right branch anastomoses with superior branch of right colic ○ Left branch anastomoses with ascending branch of left colic (watershed area, griffith’s point)

Transverse colon ● Ileocolic artery ● Terminal branch of SMA ● Superior and inferior divisions ○ Superior divisions forms anastomosis with the right colic artery and supplies the ascending colon ○ Inferior division runs towards the ileocecal junction and anastomoses with ileal branch of SMA ■ Branches: cecal arteries (anterior and posterior), appendicular artery, ileal and ascending colon ○ Terminal ileum Caecum Ascending colon Right colic artery Appendiceal artery...