Upper Abdomen

Structures of the upper abdomen are derived from embryonic foregut therefore they all receive their arterial blood supply from branches of the Celiac trunk. (the 1st of 3 unpaired branches of the descending aorta; celiac, superior mesentery, and inferior mesentery) The embryonic foregut is drained via the Portal system.

Blood supply

The Celiac trunk divides into three vessels:

(1) Hepatic artery – becomes the proper hepatic artery after giving off two branches:

Right gastric artery supplies the lesser curve of the stomach

Gastroduodenal artery gives rise to:

(a) supraduodenal artery
(b) right gastroepiploic artery – supply greater curve of the stomach
(c) the superior (anterior and posterior) pancreodoudenal arteries – supply the head of the pancreas

(2) Left Gastric artery Supplies the lesser curve of the stomach

(3) Splenic artery supplies the spleen – two branches:

Short gastric arteries supplies the fundus of the stomach

Left Gastroepiploic artery (aka left gastro-omental) supplies the greater curve of the stomach

Gall Bladder – under liver on the visceral surface. Stores bile until needed

Bile collects in right and left hepatic ducts. They join to form the common hepatic duct. Once joined by the cystic duct (drains the gall bladder) they become the Common bile duct.

[from distal to proximal] Fundus Þ body Þ neck Þ cystic duct (with spiral fold to hold duct open) Þ common bile duct

Pain from the gall bladder is felt at T5-9 and if the diaphragm superior gets irritated C3-4 (due to referred pain)

Liver – T9-10 to L1-2, protected for the most part by ribs

Anatomical divisions- Right lobe (demarcated by the gall bladder fossa and inferior vena cava); Left lobe (separated by the ligamentum teres); Caudate lobe (lies between the ligamentum venosum and inferior vena cava); Quadrate lobe (lies between the ligamentum teres and gallbladder fossa)

Physiological / 8 divisions: Right – anterior and posterior (superior and inferior for each) Left – lateral and medial (superior and inferior for each too) a portal triad goes to each segment, hepatic veins from each segment too.

Coronary ligament – the upper limits of the subphrenic recesses; the triangular ligaments are its extremes

The Portal Vein starts where the Superior Mesenteric vein meets the Splenic vein (and sometimes the Inferior mesenteric vein (connects to splenic vein)) this brings blood from the gut to the liver (the hepatic veins drain the liver)

Spleen – levels T9-12, on the left side, tail of the pancreas is nestled in the hilus of the spleen

Receives vasculature from the Splenic artery

Pancreas – retroperitoneal, head, nestled in the C shaped duodenum, body, behind the stomach, and tail, nestled in the hilus of the spleen. The head (~L2) is lower (more towards the feet) that then tail (~T11).

The head receives its blood from the Superior (anterior and posterior) pancreadoudenal arteries (off the gastroduodenal)
The rest of the pancreas gets its blood off the Splenic artery
2 ducts: 1) Main pancreatic duct – begins at the tail and joins the bile duct to form the Ampulla of Vater (hepato-pancreatic ampulla) 2) Accessory pancreatic duct – drains part of the head, usually connected to the main duct

Stomach – gets vasculature from all three branches of the Celiac trunk; left gastric, splenic (short gastrics and left gastroepiploic), and Hepatic (right gastric, right gastroepiploic).

Cardiac notch – the superior angle that lies lateral to the entrance of the esophagus.
Fundus (top of stomach, filled with air), Body (major portion of the stomach, histologically the same as the fundus), Pylorus (the distal sphincteric region that guards the pyloric orifice, thicker walls because of extra circular smooth muscle)
Pyloric sphincter- thickened circular muscle, regulates what enters the duodenum
Rugae – folds found in empty stomach
Greater curve is on the inferior side (and is longer) the Lesser curve is on the superior side (medial to esophagus)

Duodenum – 2^nd, 3^rd, and 4^th parts are retroperitoneal (fixed to the posterior wall)

"cap" or "superior", located on the right side of L1, smooth walled (plicae circularis appear in retroperitoneal sections)
"descending", located on the right side of L1, L2, and L3, where the duodenal papilla projects into the duodenum.
"horizontal", located across L3, in front of the aorta and inferior vena cava
"ascending", located on the left side of L3 (maybe L2), attached to the Ligament of Tritz (an extension from the medial crus of the diaphragm) at the duodenojejunal flexure. Where the intestine becomes intraperitoneal again.

Nerves

Parasympathetic innervation is from the anterior vagal trunk (derived from the left vagus) and the posterior vagal trunk (derived from the right vagus)

Celiac ganglion – located on either side of the celiac trunk. From the posterior vagal trunk

Sympathetic innervation is from the Splanchnic nerves

Lymphatics

Lymph nodes along the greater and lesser curvatures of the stomach drain into the cisterna chyli ("lake of lymph") and the thoracic duct.

Structures

Organs

Stomach- located in upper left quadrant, between esophagus and duodenum
Spleen- levels T9-12, on the left side, tail of the pancreas is nestled in the hilus of the spleen
Liver- T9-10 to L1-2, protected for the most part by the ribs

Miscellaneous

Omental (Epiploic) Foramen of Winslow-the communication of the lesser and greater sacs of the peritoneum. See below for boundaries
Lesser Omentum- made of the Hepatoduodenal ligament and the Hepatogastric ligament

Hepatoduodenal Ligament and its contents:

Common Bile Duct- carries bile from the gall bladder and liver as the joint duct of the cystic and common hepatic ducts
Proper Hepatic Artery- brings oxygenated blood to the liver, from the common hepatic artery (off the celiac trunk)
Portal Vein- brings blood drained from the GI tract to the liver
Autonomic Nerves-the hepatic plexus, derived from the celiac plexus, carries both sympathetic and parasympathetic fibers
Lymphatics- most of the deep lymph vessels from the liver converge at the porta hepatis (where portal vein enters liver)

Ducts:

Cystic Duct- drains the gall bladder, joins the hepatic duct to form the Common bile duct
Common Hepatic Duct- the duct formed by the convergence of the right and left hepatic ducts
Right and Left Hepatic Ducts- drain bile from the liver into the common hepatic duct

Vessels:

Celiac Trunk and Branches- 1^st of three unpaired abdominal vessels off the aorta, gives rise to the following:

(1) Left Gastric Artery- off celiac trunk, brings blood to the lesser curve of the stomach
(2) Splenic Artery- off celiac, gives rise to left gastroepiploic and short gastric arteries before going on to the spleen
(3) Common Hepatic Artery and its branches (Proper Hepatic Artery, Gastroduodenal Artery)

Right Gastric Artery (and anastomoses with Left Gastric Artery)- vascularize the lesser curvature of the stomach
Right and Left Gastroepiploic Arteries- vascularize the greater curvature of the stomach
Portal Vein and its tributaries (Splenic Vein, Superior Mesenteric Vein join to form the Portal vein)

Review

margins of the epiploic foramen

Anteriorly; the portal vein, hepatic artery, and bile duct

Posteriorly; the inferior vena cava and right crus of the diaphragm

Superiorly; the caudate lobe of the liver

Inferiorly; the superior part of the duodenum, portal vein, hepatic artery, and bile duct.

collateral circulation around the stomach

The stomach receives blood from all three branches of the celiac trunk (left gastric, common hepaticÞ right gastroepiploic and right gastric, SplenicÞ left gastroepiploic and short gastric)

coalescence of veins that form the portal vein

The inferior mesenteric vein joins the splenic vein. The splenic vein coalesces with the superior mesenteric to form the portal vein.

structures associated with the hepatoduodenal ligament

common bile duct, portal vein, common hepatic artery, lymphatics, and autonomic nerves.

The coronary and faliciform ligaments prevent the liver from moving. The liver does move slightly during respiration.

path of bile from formation to excretion into the duodenum

Bile formed in the liver goes through the right or left hepatic ducts to the common hepatic duct and then either to the gall bladder via the cystic duct or to the duodenal papilla via the common bile duct.

difference between portal and caval venous blood flow

The portal vein collects blood from the GI tract and carries it to the liver. The blood is then collected from the liver and enters the inferior vena cava via the hepatic veins. There is communication between the portal and caval (systemic drainage via the inferior vena cava)

at the gastroesophageal region, the esophageal tributaries off the left gastric vein anastomose with the esophageal veins (which empty into the azygos vein)

in the anorectal region, the superior rectal vein anastomoses with the middle and inferior rectal veins (both of which are caval in nature)

in the paraumbilical region, the paraumbilical veins in the falciform ligament anastomose with subcutaneous veins in the anterior abdominal wall.

In the retroperitoneal region, tributaries of the splenic and pancreatic veins anastomose with the left renal vein