Abdomen Flashcards
Peritoneum
Serous membrane w/ two layers
1. parietal
2. visceral
Between layers peritoneal cavity w/ serous fluid
Greater sac
accounts most of the space in peritoneal cavity
Lesser sac (Omental bursa)
small space posterior to the lesser momentum, stomach, liver and inside greater momentum; sac is created by stomach rotation and growth of liver
Communication between greater and lesser sac
Epiploic foramen (foramen of Winslow’s)
Peritoneal cavity
Males: closed cavity
Females: fallopian tube open into cavity
Peritoneal fold: stomach
lesser and greater omentum
Peritoneal fold: small intestine
mesentery
Peritoneal fold: large intestine
mesoappenix, transverse mesocolon, sigmoid mesocolon
Intraperitoneal organs
stomach, 1st part of duodenum, jejunum, ileum, appendix, transverse colon, sigmoid colon, liver, spleen
Retroperitoneal organs (SADPUCKER)
Suprarenal glands, aorta, duodenum 2-4, pancreas, ureter, colon, kidney, esophagus and rectum
Ligament
double layer of peritoneum connects an organ with another or anterior abdominal wall
Mesentery
double layer of peritoneum result from the invagination of the peritoneum by the intestine
Omentum
double layer of peritoneum passing from the stomach and first part of the duodeunm to adjacent organs
greater omentum –> greater curvature
lesser omentum –> lesser curvature
Nerve supply: Parietal peritoneum
somatic nerves of the overlying muscles and skin
Nerve supply: Visceral peritoneum
Autonomic nerves with the underlying viscera (does not receive somatic (pain) but receives sympathetic (stretch, tension))
Blood supply: foregut
celiac trunk (T12)
Blood supply: midgut
superior mesenteric artery (L1)
Blood supply: hindgut
inferior mesenteric artery (L3)
Organs arising from foregut
stomach, liver, gallbladder, pancreas, 1st half of duodenum
Organs arising from midgut
2nd half of duodenum, jejunum, ileum, cecum, ascending colon, 2/3 transverse colon
Organs arising from hindgut
L 1/3 transverse colon, descending colon, sigmoid colon, rectum
Stomach dilation can occur because of…
rugae (folds in the mucosa)
Stomach bed
Structures posterior to the stomach separated by lesser sac
Speen
4 L (L kidney, L suprarenal, L colic flexure, L crus of diaphragm)
4 T (transverse colon, mesocolon, body of pancreas, splenic artery)
Hepatogastric ligament
Porta hepatis of liver to lesser curvature of stomach
lesser omentum - ventral mesentery
Hepatoduodenal ligament
Porta hepatis of liver to the 1st part of duodenum
lesser omentum - ventral mesentery
Greater omentum
Dorsal mesentery Policeman of the abdomen -gastrosplenic -gastrcolic -splenorenal
Fissures of the liver
- Fissure for ligamentum venosum (from ductus venous)
- Fissure for ligamentum teres (round ligament)
- Foss of gall bladder
- Fissure for IVC
- Porta Hepatis
Porta Hepatis
lies transversely between the quadrate and caudate lobes
Structures: portal vein, hepatic artery, hepatic duct (from posterior to anterior)
Anatomical lobes of liver
Right lobe contains caudate and quadrate divided by falciform ligament, fissure for ligamentum theres and venosum
Function lobes of liver
Left lobe contains caudate and quadrate (division based on blood supply) divided by fossa of gallbladder and IVC
Physiological blood supply to the liver
Hepatic artery: 25% blod and 50% oxygen demand
Portal vein: 75% of blood and 50% oxygen demand
Sphincter of Oddi
Layer of circular muscle surrounding the lower end of bile duct, pancreatic duct and ampulla controlling the flow of bile and pancreatic secretions
Location of the fundus of gall bladder
meeting point between the right line semilunaris and the 9th right costal cartilage (sight of tenderness for gall bladder inflammation)
Common site for gall bladder stones
Hartmann’s pouch - posteromedial wall, neck of the gallbladder
Venous drainage of the liver
sinusoids–>central veins–>hepatic v. –> IVC
Vessels transmitted within gastrosplenic ligament?
short gastric and gastro-omental
Location of the spleen
Left posterior, very close to 9,10,11 ribs, wedged between stomach and left kidney
Duodenum
C shaped tube surrounding head of pancreas; pylorus to duodenojejunal flexure
1st part: lies at L1, peritoneal, attached to the greater and lesser omentum, duodenal cap –> duodenal ulcers
2n part: lies from L2-3, retroperitoneal, receives major and minor duodenal papilla
3rd: lies at L3, retroperitoneal
4th: lies from L3-2, retroperitoneal, duodenojejunal flexure tethered by the ligament of treitz
Divisions of the SMA
inferior pancreaticoduodenal middle colic right colic ileocolic (appendicular, ileal) Ilieal/ jejunal (12+)
SMA
artery of the midgut
arises from abdominal aroma at L1
runs right toward iliac fossa
all branches to the right except jejunal and ileal
IMA
artery of handgun arises from the abdominal aorta at L3 runs left towards iliac fossa all branches to the left ends by becoming superior rectal artery (once it crosses the left common iliac artery)
Divisions of IMA
Left colic
Sigmoid arteries (2-3)
Superior rectal artery
Anatomies between the GI arteries
- Pancreaticoduodenal (superior from celiac trunk, inferior from SMA)
- Marginal artery (between SMA and IMA)
Pancreatic ducts
- main pancreatic duct (of Wirsung) joins the common bile duct and empties into the hepatopancreatic ampulla (ampulla of Vater)- 2nd part of duodenum
- accessory pancreatic duct- drains the uncinate process at the min papilla, proximal to the main papilla
Appendices epiploicae (omental appendices)
small pouches filled with fat, absent in cecum, appendix and rectum (CAR)
Taeniae coli
outer longitudinal muscle layer is thickened to form three bands which are shorter than the outer layers, they begin at the base of appendix and end at sigmoid colon
Sacculations (haustra)
between the taeniae coli the colon bulges outwards forming three rows of pouches
Peritoneal folds: Cecum
retroperitoneal
Peritoneal folds: appendix
mesoappendix
Peritoneal folds: ascending colon
retroperitoneal
Peritoneal folds: transverse colon
transverse mesocolon
Peritoneal folds: descending colon
retroperitoneal
Peritoneal folds: sigmoid colon
sigmoid mesocolon
Peritoneal folds: rectum
retroperitoneal
Ileocecal valve
guards the ideal opening into the cecum; valve has 2 lips; opening to appendix lies two cm below
Appendix
blind ending tube, rich in lymphoid tissue, suspended by mesoappendix; the three taeniae coli meet at the base of the appendix
Acute appendicitis
acute inflammation of the appendix due to viral or bacterial infection; infection of the appendix may result in thrombosis of the appendicular artery (branch of ileocolic artery) which may lead to perforation of the appendix
McBurney’s point
the point of maximum tenderness in acute appendicitis ; lies opposite the junction of lateral and middle thirds of a line joining the Rt ASIS to the umbilicus; pain from the appendix enter the spinal cord through T10 segment so pain of acute appendicitis is refereed to the umbilicus region
Meckel’s diverticulum (syndrome of Two’s)
2 ft from IC valve, 2 inches long, 2% of population, 2% are symptomatic, 2 types of ectopic tissue (gastric and pancreatic), 2 years of age at clinical presentation, and 2x more common in boys
Inflammation of Meckel’s diverticulum
Most common appendix
pelvic appendix
Portal vein anastomes
- gastric and esophageal (azygos)
- paraumbilical and epigastric (iliac vein)
- s. rectal and inferior rectal (rectal vein)
Liver cirrhosis effect on portal vein
Portal hypertension leads to increased pressure in tributaries, dilation of veins becoming fragile will causing bleeding at anastomes
- inferior esophagus bleeding
- inferior rectum bleeding
- caput medusae (varices around navel)
Parasympathetic innervation on the gut
Foregut and midgut- vagus nerves
Hindgut- pelvic spanchnic nerves (S2,3,4)
Sympathetic innervation on the gut
Foregut and midgut- thoracic splanchnic nerves (greater, lesser, least)
Hindgut- lumbar splanchnic nerves
Three splanchnic nerves
Greater = T5-T9 Lesser = T10-T11 Least = T12
Layers of the posterior abdominal wall
- Bony layer: iliac bone, lumbar vertebrae, last 2 ribs
- Muscle layer
- Fascia
- Visceral layer: kidney, ureter, suprarenal, abdominal aorta, IVC
- Partial peritoneal layer
Diaphragm openings
T8- IVC
T10- Esophagus
T12- Aorta
“i ate ten eggs at noon”
Regions of the diaphragm
Right and left copula (right is higher due to liver)
Central tendon
Origin of the diaphragm
sternal: xiphoid process
costal part: lower 6 costal cartilages
vertebral (lumbar): 2 crura and 5 ligaments
Vertebral origin of the diaphragm
Right crus: upper three bodies of lumbar vertebrae, forms esophageal hiatus, forms the suspensory ligament of duodenum
Left crus: arises from bodies of upper 2 lumbar
Median arcuate ligament: unites crura across aorta, forming aortic hiatus
Medial arcuate ligament: tendinous arch across the upper part of posts major
Lateral arcuate ligament: tendinous arch across the quadrates lumborum
Lumbar plexus: T12
subcostal nerve
runs in front of quadratus lumborum
Lumbar plexus: L1
Iliohypogastric nerve
Ilioinguinal nerve
runs in front of quadratus lumborum and pierce internal oblique to run between it and external oblique
Lumbar plexus: L1, L2
genitofemoral
pierces posas major
Lumbar plexus: L2, L3
lateral cutaneus thigh
lateral to psoas major
Lumbar plexus: L2,3,4
Femoral nerve- between iliac and psoas major
Obturator nerve- white round glistening, medial to psoas major
Sites of constriction of ureter
Ureter may be obstructed by renal calculi (kidney stones) in three areas:
- Uretero-pelvic junction- where it joins the renal pelvis
- Pelvic inlet- crosses the pelvic brim over the distal end of the common iliac artery
- Ureterovesicular junction- enters the wall of the urinary bladder (narrowest point of the ureter)
Arteries to the suprarenal gland
- Superior suprarenal artery from the inferior phrenic artery
- Middle suprarenal artery from abdominal aorta
- inferior suprarenal artery from the renal artery
Suprarenal drainage
Right empties into the IVC
Left empties into the left renal vein
Cisterna chyli
lower dilated lymphatic sac at the end of the thoracic duct and lies just to the right and posterior to the aorta, usually between two crura of the diaphragm
formed by the intestinal and lumbar lymph trunks, narrows superiorly and gives the thoracic duct
