Abdomen 2 Flashcards
Peritoneum
Single continuous layer of squamous epithelium called mesothelium
Part which wraps around viscera is visceral peritoneum
Other parts are parietal peritoneum
Mesentery
Fold in peritoneum that allow communication of intraperitoneal organs with abdo wall
Nerves and vessels pass through
Entire gut has dorsal mesentery
Foregut has ventral mesentery
Secondary retroperitoneal organs
In contact with wall
Lose mesentery
2-4th part of duodenum
Pancreas (tail is intraperitoneal)
Ascending and descending colon
Primary retroperitoneal organs
Develop posterior to peritoneal cavity so never have mesentery
Kidneys and ureters Suprarenal glands Aorta and IVC Lumbar plexus, sympathetic trunk Oesophagus Rectum
What forms in foregut dorsal mesentery
Premature spleen
What forms in ventral mesentery
Premature liver
Ventral ligaments
Liver splits ventral foregut mesentery into:
Falciform ligament
Lesser omentum
Dorsal ligaments
Spleen splits dorsal foregut mesentery into:
Gastrosplenic ligament
Splenorenal ligament
Omental bursa
Pocket of peritoneal cavity
Lesser sac behind stomach and liver
Rest become greater sac
Only connected by Omental foremen under lesser omentum
Lesser omentum
Made up of two ligaments:
Hepatogastric
Hepatoduodenal
Portal triad
Near inferior end of lesser omentum
Common bile duct
Portal vein
Hepatic artery
Liver lobes
Divided by Falciform ligament into two
Liver ligaments
Attaches to diaphragm or posterior abdominal wall via triangular ligaments
Liver structure
Hepatocytes arranged into lobules
Central vein drain into each lobule to hepatic vein
Portal triad seen at periphery of each lobule
Portal circulation
Gallbladder
Fundus, body, neck
Cystic duct and spiral valves
Hepatic duct and common bile duct
Hepatopancreatic ampulla of Vater
Pancreatic duct
Gallstones
Fever, jaundice, RUQ pain
Cholelithiasis - uncomplicated
Choledocholithiasis - gallstone in CBD - progress to ascending cholangitis (Charcot’s triad)
May radiate to right shoulder of phrenic nerve irritated
Lower oesophageal sphincter
Diaphragm contributes to formation
Hiatus hernia
Sliding and rolling
Part of stomach protrude through oesophageal hiatus
Stomach
Fundus
Body
Pyloric antrum
Pyloric canal - muscular sphincter at end to prevent food entering duodenum
Duodenum
First part - common for ulcers
Second part - major duodenal papilla - entrance of common bile duct
Small intestine
Duodenum - jejunum proximal 2/5 - ileum distal distal 3/5
Villi and valvulae conniventes
Large intestine
Begin at ileocaecal valve
End at rectum
Ascending, transverse (from right to left colic flexure) , descending, sigmoid
Taeniae coli, haustra, appendices
Abdominal aorta branches
Coeliac trunk Superior mesenteric artery Renal artery Gonadal artery Inferior mesenteric artery Common iliac artery
Can smoking really give intestinal cancer
Blood supply for regions of gut
3 unpaired arteries
Connect to intraperitoneal viscera by dorsal mesenteric
Foregut - coeliac trunk - liver, pancreas, spleen
Midgut - SMA - intestines and colon
Hindgut - IMA - colon and rectum
Stomach arteries
Coeliac trunk:
Common hepatic, left gastric and splenic
Right gastric and gastroduodenal (from common hepatic) Left gastric (branch of splenic)
Liver and gallbladder arteries
Right and left hepatic arteries (from proper hepatic - common hepatic)
Cystic artery
Colon arteries
Caecum - ileocolic SMA
Ascending - right colic SMA
Transverse and right colic flexure - middle colic SMA
Left colic flexure - anastomosis of middle and left colic SMA and IMA
Descending - left colic IMA
Sigmoid - sigmoid IMA
Rectum - rectal IMA
SMA branches
Jejunal Ileal Ileocolic Right colic Middle colic
IMA branches
Left colic
Sigmoid
Superior rectal
Jejunum vs Ileum
Jejunum has larger diameter, less prominent arterial arcades, longer vasa recta
Venous drainage of gut
Into portal system
Posterior to first part of duodenum the portal vein forms
Foregut - portal and splenic
Midgut - SMV
Hindgut - IMV which empties into splenic vein
Portosystemic anastomosis
Oesophageal and left gastric vein - oesophageal varices
Superior and inferior rectal veins - haemorrhoids
Para umbilical and epigastric vein - caput Medusa
Lymphatics
Follow arterial supply
Coeliac, SM and IM
All drain into cisterna Chyli (elongated lymphatic sac in front of L1 and 2) - thoracic duct commences here
Referred Pain
Retroperitoneal organ pain – presents as back pain
Appendicitis – when irritating visceral peritoneum - presents as umbilical pain.
When irritating parietal peritoneum (i.e. appendix has become more inflamed) - presents as RLQ pain
Irritation of diaphragm – presents as shoulder tip pain
Visceral peritoneal organ pain referred to skin supplied by same nerve segment
Parasympathetic nerve supply of the stomach
Anterior and posterior vagal trunks and their branches, which enter the abdomen through the esophageal hiatus.
anterior vagal trunk
Mainly from the left vagus nerve (CN X).
It runs toward the lesser curvature of the stomach, where it gives off hepatic and duodenal branches, which leave the stomach in the hepatoduodenal ligament.
The rest of the anterior vagal trunk continues along the lesser curvature, giving rise to anterior gastric branches.
posterior vagal trunk
Mainly from the right vagus nerve, passes toward the lesser curvature of the stomach.
Supplies branches to the anterior and posterior surfaces of the stomach.
It gives off a celiac branch, which passes to the celiac plexus, and then continues along the lesser curvature, giving rise to posterior gastric branches.
sympathetic nerve supply of the stomach
From the T6 through T9 segments of the spinal cord, passes to the celiac plexus through the greater splanchnic nerve and is distributed through the plexuses around the gastric and gastro-omental arteries.
Anatomical variations in the position of the appendix
Retrocaecal
Gastric lymphatics
Lymph from the superior two thirds of the stomach drains to the gastric lymph nodes; lymph from the fundus and superior part of the body of the stomach drain to the pancreaticosplenic lymph nodes.
Lymph from the right two thirds of the inferior third of the stomach drains to the pyloric lymph nodes.
Lymph from the left one third of the greater curvature drains to the pancreaticoduodenal lymph nodes.
Arteries of duodenum
The celiac trunk, via the gastroduodenal artery and its branch, the superior pancreaticoduodenal artery, supplies the duodenum proximal to the entry of the bile duct into the descending part of the duodenum.
The superior mesenteric artery, through its branch, the inferior pancreaticoduodenal artery, supplies the duodenum distal to the entry of the bile duct.
Lymphatics of duodenum
The anterior lymphatic vessels drain into the pancreaticoduodenal lymph nodes, and into the pyloric lymph nodes.
The posterior lymphatic vessels drain into the superior mesenteric lymph nodes. Efferent lymphatic vessels from the duodenal lymph nodes drain into the celiac lymph nodes.
Lymphatics of jejunum and ileum
Mesenteric lymph nodes: scattered among the arterial arcades.
Efferent lymphatic vessels from the mesenteric lymph nodes drain to the superior mesenteric lymph nodes.
Lymphatic vessels from the terminal ileum follow the ileal branch of the ileocolic artery to the ileocolic lymph nodes.
Nerve supply of jejunum and ileum
The sympathetic fibers in the nerves to the jejunum and ileum originate in the T8–T10 segments of the spinal cord and reach the superior mesenteric nerve plexus through the sympathetic trunks and thoracic abdominopelvic (greater, lesser, and least) splanchnic nerves.
Nerve supply of caecum and appendix
Superior mesenteric plexus
The sympathetic nerve fibers originate in the lower thoracic part of the spinal cord, and the parasympathetic nerve fibers derive from the vagus nerves. Afferent nerve fibers from the appendix accompany the sympathetic nerves to the T10 segment of the spinal cord
Lymphatic drainage of the cecum and appendix
Lymph nodes in the meso-appendix and to the ileocolic lymph nodes that lie along the ileocolic artery.
Efferent lymphatic vessels pass to the superior mesenteric lymph nodes.
lymphatic drainage of colon
Ascending - Epicolic and paracolic lymph nodes, to the superior mesenteric lymph nodes
Transverse - middle colic lymph nodes, which in turn drain to the superior mesenteric lymph nodes
Descending and sigmoid - Epicolic and paracolic nodes and then through the intermediate colic lymph nodes. Lymph from these nodes passes to the inferior mesenteric lymph nodes.
Lymphatics of liver
Superficial lymphatics in the subperitoneal fibrous capsule of the liver, which forms its outer surface, and as deep lymphatics in the connective tissue.
Most lymph is formed in the perisinusoidal spaces and drains to the deep lymphatics in the surrounding intralobular portal triads.
Nerves of liver
From the hepatic plexus, the largest derivative of the celiac plexus.
This plexus consists of sympathetic fibers from the celiac plexus and parasympathetic fibers from the anterior and posterior vagal trunks.
Veins of bile duct
Enter the liver directly. The posterior superior pancreaticoduodenal vein drains the distal part of the bile duct and empties into the hepatic portal vein or one of its tributaries.
Lymphs of bile duct
Cystic lymph nodes near the neck of the gallbladder, the lymph node of the omental foramen, and the hepatic lymph nodes. Efferent lymphatic vessels from the bile duct pass to the celiac lymph nodes.
Lymphs of gallbladder
Hepatic lymph nodes, often through cystic lymph nodes located near the neck of the gallbladder. Efferent lymphatic vessels from these nodes pass to the celiac lymph nodes.
Nerves of gallbladder and cystic duct
Cystic artery from the celiac (nerve) plexus and the vagus nerve (parasympathetic). The right phrenic nerve (somatic afferent fibers) may carry pain caused by gallbladder inflammation.
