103 - Vessels, Nerves, Lymphatics of the Abdomen Flashcards
Where does the abdominal aorta start?
~T12/L1
Where does the AA divide into the common iliac arteries?
L4
Branches of the AA 1 2 3
1) 3x unpaired anterior branches 2) 3x paired lateral branches 3) Series of paired posterior branches
What do the posterior branches of the AA supply?
The walls of the aorta (including the diaphragm). The phrenic artery (for diaphragm) and lumbar arteries for abdominal walls.
What do the three paired branches of the AA supply? 1 2 3
1) Kidneys (left and right renal) 2) Adrenals (left and right suprarenal) 3) Gonads (left and right gonadal, testicular/ovarian)
What do the three unpaired anterior branches of the AA supply?
Abdominal viscera
Three unpaired branches of the AA
1) Coeliac 2) Superior mesenteric 3) Inferior mesenteric
Artery supplying derivatives of the primitive foregut
Coeliac artery
Artery supplying derivatives of the primitive midgut
Superior mesenteric artery
Artery supplying derivatives of the primitive hindgut
Inferior mesenteric artery
Structures supplied by the coeliac artery
Liver, gallbladder, pancreas, spleen, abdominal oesophagus, stomach, duodenum up to the major duodenal papilla
Structures supplied by the superior mesenteric artery
Duodenum from the major duodenal papilla until the transverse colon, proximal to the splenic flexure
Structures supplied by the inferior mesenteric artery
Last part of the transverse colon until the anal canal
Where does the coeliac trunk branch from the AA?
~T12
Branches from the coeliac trunk 1 2 3
1) Left gastric artery 2) Splenic artery 3) Common hepatic artery
Path of the left gastric artery 1 2 3 4
1) First unpaired anterior artery to branch form the AA. 2) Travels upwards, to the left. 3) Gives branches to abdominal oesophagus. 4) Runs along lesser curvature of stomach
Path of the splenic artery 1 2 3
1) Runs along superior border of the pancreas towards the hilum of the spleen. 2) Sends short gastric arteries to fundus of the stomach. 3) Sends left gastroepiploic arteries that line greater curvature
Structures supplied by splenic artery 1 2 3 4
1) Body, tail of the pancreas 2) Spleen 3) Fundus of stomach 4) Left gastroepiploic branches line greater curvature of stomach.
Path of the common hepatic artery 1 2 3 4 5 6 7
1) Travels to the right, to the free edge of the lesser omentum. 2) Splits into proper hepatic artery and gastroduodenal artery. Right gastric artery branches from common hepatic artery. 3) Proper hepatic artery ascends free edge of lesser omentum, then splits into right and left hepatic arteries. 4) Cystic artery often branches from right hepatic artery (variable) 5) Gastroduodenal artery descends, travels under 1st part of duodenum. 6) Right gastroepiploic artery branches to greater curvature under 1st part of duodenum. 7) Anterior superior pancreaticoduodenal artery branches.
* Coeliac trunk
COELIACARTERY
Branches of the superior mesenteric artery 1 2 3 4
1) Inferior pancreaticojejunal artery 2) Jejunal arteries 3) Ileac arteries 4) Colic arteries
Where does the superior mesenteric artery branch from the AA?
L1
Path of the superior mesenteric artery 1 2 3 4 5
1) Branches at L1 2) gives off inferior pancreaticoduodenal branch 3) Travels over the duodenum, aorta, right psoas 4) Branches to the left supply the small intestine (jejunal, ileac arteries) 5) Branches to the right supply the large intestine (colic arteries)
Path of colic arteries 1 2 3
1) Branch to the right from the superior mesenteric artery 2) Ileocolic, right colic, middle colic arteries 3) Colic arteries feed marginal artery that runs alongside the large intestine, branches from which supply large intestine.
Where does the inferior mesenteric artery branch?
L3
How does the inferior mesenteric leave the aorta?
Travels inferolateral from L3 into the lower left quadrant
Path of the inferior mesenteric artery
Gives off a series of colic branches, before becoming superior rectal artery
Venous drainage of viscera
All visceral veins drain into a single portal vein, which enters the liver at the porta hepatica
Where does the portal vein originate?
Behind the neck of the pancreas at T12. Where the splenic vein joins the superior mesenteric vein
Where does the portal vein drain after travelling through the liver?
Into the IVC, just before it penetrates the diaphragm
Where do the hepatic veins drain?
Into the IVC
Danger of liver fibrosis
Because portal system is low pressure, fibrosis can occlude blood flow into the liver if it results in an elevation of pressure within the hepatic portal system
Effect of portal hypertension 1 2 3 4
1) Portal veins don’t have valves, so blood backs up. 2) Direction of flow is reversed. 3) Anastamoses are formed so that blood can return to the heart via the systemic venous circulation (porto-systemic anastamoses) 4) This can occur in five places
Five places where porto-systemic anastamoses can occur 1 2 3 4 5
1) Distal end of oesophagus 2) Anal canal (superior rectal vein fuses with portal system) 3) Anterior abdominal wall veins (opens ligamentum teres into the umbilical vein) 4) Retroperitoneal space behind colon 5) Trop of the liver, where it presses against the diaphragm
Danger of porto-systemic anastamoses forming at the distal oesophagus
Oesophageal varices can form, which bleed profusely
Which nervous system innervates abdominal viscera?
Autonomic
Spinal segments from which preganglionic sympathetic fibres innervating GIT originate
T6 - L2
Where do the sympathetic ganglia cluster in the abdomen?
Unpaired branches of aorta, renal arteries
Parasympathetic innervation of midgut and foregut
Vagus
Parasympathetic innervation of the hindgut
Pelvic splanchnic nerves
How do post-ganglionic fibres innervate targets?
Pass to targets with blood vessels
Segments supplying autonomic innervation to foregut
T6 - T9
Segments supplying autonomic innervation to midgut
T8 - T12
Segments supplying autonomic innervation to hindgut
T12 - L2
Afferents from viscera until the mid-sigmoid colon
Run with sympathetic innervaiton
Referred pain from unpaired viscera until mid-sigmoid colon
Refer pain to anterior abdominal wall (dermatones T6 - L2)
Referred pain from unpaired viscera after mid-sigmoid colon
Refer pain to perineal region (dermatomes S2 - S4)
