Abdominal Aorta & Coeliac Trunk

 ABDOMINAL  AORTA

(Find the Video Tutorial Here

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https://www.youtube.com/watch?v=SD8pLsfurXc&t=13s)

Course :-

Abdominal aorta begins as a continuation of descending thoracic aorta at the aortic opening of the diaphragm, opposite the lower border of T12 vertebra.

It passes downwards in front of vertebral column and on the left side of inferior vena cava.

It ends by dividing into right and left common iliac arteries opposite the body of L4 vertebra, slightly to the left of median plane.

Relations :-

In Front –

• Origin of coeliac artery
• Coeliac plexus of nerves
• Covered by peritoneum of lesser sac
• Origin of superior mesenteric artery
• Body of pancreas
• Splenic vein
• Left renal vein
• Origin of inferior mesenteric artery
• Third part of duodenum

Behind –

• Bodies of upper four lumbar vertebrae
• Intervertebral discs
• Anterior longitudinal ligament
• Origin of four pairs of lumbar arteries
• Median sacral artery
• Third & fourth left lumbar veins
• Left psoas major muscle

Right side –

• Inferior vena cava
• In the upper part – cisterna chyli, thoracic duct, azygos vein, right crus of diaphragm, right coeliac ganglion

Left side –

• Left crus of diaphragm
• Left coeliac ganglion
• Duodeno-jejunal flexure
• Left sympathetic trunk
• Inferior mesenteric artery

Branches :-

• They are arranged into 4 groups – ventral, lateral, dorsal and terminal.

Ventral branches –

• Coeliac artery- it is the artery of fore gut and arises opposite the lower border of T12 vertebra.
• Superior mesenteric artery- it is the artery of mid gut and arises opposite the lower border of L1 vertebra.
• Inferior mesenteric artery- it is the artery of hind gut and arises opposite L3 vertebra.

Lateral branches –

• Inferior phrenic arteries
• Middle supra-renal arteries
• Renal arteries
• Gonadal (Testicular or Ovarian) arteries

Dorsal branches –

• Four pairs of lumbar arteries
• Median sacral artery

Terminal branches –

• Right and left common iliac arteries 

COELIAC  TRUNK

• It is a short wide vessel about 1.25 cm long.
• It arises from the front of aorta below the aortic opening of diaphragm, opposite the lower border of T12 vertebra.
• Its origin is sandwiched between the tuber omentale of pancreas below & papillary process of liver above.
• It is surrounded by coeliac plexus of nerves.
• The trunk divides into 3 branches – left gastric, common hepatic & splenic arteries.

LEFT  GASTRIC  ARTERY :-

• It is the smallest branch of coeliac trunk.

It passes upwards and to the left behind the omental bursa towards the cardiac end of stomach

Then arches forwards along the left gastro-pancreatic fold

Reaches the lesser curvature of stomach

Within the lesser omentum it anastomoses with right gastric artery

Close to the cardiac orifice it provides a few ascending oesophageal branches.

COMMON  HEPATIC  ARTERY :-

It passes to the right behind the omental bursa along the upper border of body and neck of the pancreas

Reaches the upper border of first part of the duodenum

Passes beneath the peritoneal floor of the epiploic foramen along the right gastro-pancreatic fold

Here it gives origin to the right gastric & gastro-duodenal arteries

Thereafter, it enters the right free margin of the lesser omentum

It continues upwards in front of the epiploic foramen as hepatic artery proper

Here it is accompanied with portal vein posteriorly & bile duct on its right side

Close to the porta hepatis the hepatic artery proper divides into right & left branches.

The right hepatic artery gives origin to cystic artery.

Right  Gastric  Artery :-

• It passes to the left within the lesser omentum along the lesser curvature of stomach & anastomoses with the left gastric artery.

Gastro-duodenal  Artery :-

It runs downwards behind the first part of duodenum

Lodges in a groove on the anterior surface at the junction of head and neck of pancreas

Here it divides into superior pancreatico-duodenal & right gastro-epiploic arteries.

• Sometimes, it provides a supraduodenal branch which supplies the upper margin of proximal half of the first part of duodenum.

Superior pancreatico-duodenal artery –

• It subdivides into anterior & posterior branches.
• They lodge in the corresponding pancreatico-duodenal grooves & anastomose with respective branches of inferior pancreatico-duodenal artery.

Right gastro-epiploic artery –

It passes to the left close to greater curvature of stomach

Runs within the anterior two layers of greater omentum & anastomoses with left gastro-epiploic branch of splenic artery.

• It provides branches to the stomach and greater omentum.

Cystic  Artery :-

It passes downwards and to the right behind the common hepatic duct

Lies posterior-superior to the cystic duct

At the neck of gall bladder it divides into superficial and deep branches.

• Superficial branch supplies the peritoneal inferior surface of gall bladder.
• Deep branch runs between the liver and superior surface of gall bladder.

SPLENIC  ARTERY :-

• It is the largest branch of coeliac trunk & tortuous.

It passes to the left behind the omental bursa along the upper border of body & tail of pancreas

It crosses in front of the left crus of diaphragm, left psoas major, left sympathetic trunk, left suprarenal gland & left kidney

Then enters between the two layers of lieno-renal ligament

Reaches the hilum of spleen & divides into 5 or more segmental branches.

• It also gives off pancreatic, short gastric & left gastro-epiploic arteries.

Pancreatic  Branches :-

• They are numerous.
• They supply entire pancreas except the head.
• One of the pancreatic branches is large known as arteria pancreatica magna which accompanies the main pancreatic duct on the posterior surface of body of pancreas.
• A dorsal pancreatic branch usually arises, which bifurcates into right & left branches.

Short  Gastric  Branches :-

• They are 3 – 7 in number.
• They arise from terminal part of splenic artery.
• They pass between the layers of gastro-splenic ligament & supply fundus of stomach.

Left  Gastro-Epiploic  Artery :-

• It is derived from the terminal part of splenic artery close to the hilum of spleen.

It passes downwards and to the right through gastro-splenic ligament

Then enters between the anterior two layers of greater omentum

It runs about one finger’s breadth below the greater curvature

Provides branches to both surfaces of stomach & greater omentum

Terminal part of the artery continues as omental branch

It forms a looped course within the greater omentum and anastomoses with right gastro-epiploic artery.

APPLIED  ASPECTS :-

• Sometimes, coeliac & superior mesenteric arteries arise as a common trunk.
• Inferior phrenic arteries may arise from the coeliac trunk.
• Common hepatic artery may arise from the superior mesenteric artery or directly from the aorta.
• Accessory right hepatic artery may arise from the superior mesenteric artery.
• Occasionally the accessory left hepatic artery arises from the left gastric artery.
• Cystic artery may arise from the left hepatic artery or hepatic artery proper or gastro-duodenal artery or superior mesenteric artery or right gastric artery or directly from the coeliac trunk.
• Obstruction of the common hepatic artery proximal to the right gastric artery may save the liver from necrosis, due to establishment of collateral circulation between the gastric and gastro-epiploic arteries.