Shared Flashcard Set


GI I Exam I Anatomy
Based on review per Sheedo's email

Additional Anatomy Flashcards




Transpyloric Plane

[image]Lies at tips of the 9th costal cartilage and body of L1

Passes through the pylorus of the stomach, fundus of gallbladder, neck of pancreas, hila of kidneys, and duodenojejunal junction

Midclavicular planes
left and right and at midpoint of clavicle to midinguinal point
Subcostal plane
10th costal cartilages and body of L3
Transumbilical plane
umbilicus and posteriorly at the IV disc between 3-4
Median plane
Lies at the position of the linea alba
Contents of right upper quadrant
Right lobe of liver
Pylorus of stomach
Duodenum (1-3)
Head of pancreas
Right adrenal gland
Right kidney
Right colic flexure
Superior part of ascending colon
Right half of transverse colon
Contents of Left Upper Quadrant
Left lobe of liver
Jejunum and proximal ileum
Body and tail of pancreas
Left adrenal gland
Left kidney
Left colic flexure
Superior part of descending colon
Left half of transverse colon
Contents of Right Lower Quadrant
Most of the ileum
Inferior part of ascending colon
Right ureter
Urinary bladder (if full)
Right ovary
Right uterine tube
Uterus (if enlarged)
Right spermatic cord
Contents of Left Lower Quadrant
– sigmoid colon, inferior part of descending colon, left ureter, urinary bladder if full, left ovary/uterine tube, uterus if enlarged, left spermatic cord
Direct inguinal hernia
1/3 of inguinal hernias; enters through a weakness in the fascia of the abdominal wall; protrudes through the area of the transversalis fascia in Hesselbach’s triangle; found medial to inferior epigastric vessels
• Hesselbach’s triangle – bounded by rectus abdominis muscle, inguinal ligament and inferior epigastric vessels
Indirect inguinal hernia
are most common of all inguinal hernias; 2/3 of inguinal or 50% of all; movement of the abdominal content through the deep inguinal ring within the inguinal canal exiting the superficial inguinal right. Intestine can enter the scrotum; found lateral to inferior epigastric vessels
Femoral hernia
more common in females; hernia pushed into femoral canal, femoral ring, below the inguinal ligament and between the lacunar ligament and the femoral vein; lies inferior and lateral to the pubic tubercle and inferior to the inguinal ligament
Spigelian hernia
lateral ventral; rare; through spigelian fascia (aponeurotic layer between the rectus abdominis muscle medial and the linea semilunaris lateral); occurs usually on the right side at or below the arcuate line due to the lack of posterior rectus sheath; usually small thus strangulation is common.
Internal hernia
diaphragm – occurs as a result of a defect in the development of the diaphragm; results in abdominal contents entering the thorax and can affect the respiratory system
Flow of infectious material within the abdomen
• Hepatorenal recess – deep recess of the peritoneal cavity on the right side extending upward between the liver anterior and the kidney and suprarenal gland posterior; gravity-dependent portion of peritoneal cavity when in supine position; fluids from lesser sac drain into the hepatorenal recess; epiploic foramen passes deep to the hepatoduodenal ligament; subphrenic recess and right lateral paracolic gutter open into this.
- Inflammatory exudate drains from the subphrenic recess into the paracolic gutters. To avoid accumulation of fluid in the subphrenic spaces a patient sits up at a 45 degree angle so the peritoneal fluid drains into the pelvic cavity
- Exudate from the medial paracolic gutter on the right side would remain within this region b/c of the intestinal mesentery blocking its exit
External abdominal oblique m.
•O – lower 8 ribs at inferior border
•I – iliac crest and linea alba
•F – compresses and supports the viscera within the abdomen and flex and rotate the trunk; keeps organs in cavity
•N – 7-12 intercostal nerves and L1 spinal nerves
•Fibers run Down and In
•Superficial inguinal ring – opening in external abdominal oblique muscle found adjacent to pubic tubercle; posterior wall is conjoint tendon
Internal abdominal oblique muscle
•O – inguinal ligament and iliac crest
•I – cartilages of last 3-4 ribs and linea alba
•F – compresses and supports the viscera within the abdomen and flex and rotate the trunk; keeps organs in cavity
•N – 7-12 intercostal nerves and L1 spinal nerve
•Fibers are up and in
Transversus Abdominis muscle
•O – inguinal ligament, iliac crest, and last 6 ribs
•I – linea alba
•F – compresses and supports the viscera within the abdomen and assists in forced expiration
•N – 7-12 intercostal, iliohypogastric and ilioinguinal nerves (last two are both from L1 ventral rami)
Rectus abdominis muscle
•O – pubic symphysis
•I – 5-7 ribs and xiphoid process
•F – compresses and supports the viscera within the abdomen and flexes vertebral column and is an accessory muscle of respiration
•N – 7-12 intercostal nerves
Pyramidalis muscle
•O – pubis
•I – linea alba
•F – tenses linea alba
•N – 12th thoracic nerve
Components of the rectus sheath
•Above costal margin there is only the anterior part that lies on the costal cartilages. The posterior part is absent.
•Between the costal margin and the arcuate line both the anterior and posterior parts are present. These entrap the rectus abdominis muscle.
•Between the arcuate line and the pubic crest there is only the anterior part. The posterior is absent. This is significant because it makes this area weaker to herniation.
•Contents – rectus abdominis and pyramidalis muscles, superior and inferior epigastric arteries and veins, lymphatic vessels, terminal part of ventral primary rami of T7-T12 spinal nerves
Lymph drainage from anterior wall of the stomach - superficial
•Above umbilicus drain to axillary lymph nodes
•Below umbilicus drain to superficial inguinal nodes
Lymph drainage of the anterior wall of the stomach - deep
•Lumbar nodes
•Common iliac nodes
•External iliac nodes
Lesser omentum
connects stomach at lesser curvature of stomach and the first part of the duodenum to the liver; posterior to the left lobe of the liver and is attached to the liver and the ligamentum venosum and the porta hepatis (hilum of the liver); consists of the hepatogastric (extends from the lesser curvature of the stomach to the liver) and hepatoduodenal ligament (extends from the first segment of the duodenum to the liver)
Greater omentum
greater curvature of stomach to transverse colon, diaphragm and spleen; contains gastrocolic ligament (from inferior border of stomach to transverse colon) gastrophrenic ligament (stomach to diaphragm) and gastrosplenic ligament (connects greater curvature of stomach to hilum of spleen)
Peritoneal ligaments
splenorenal ligament (derived from peritoneum, extends from wall of cavity to omental bursa between the left kidney and spleen) and phrenicocolic ligament (fold of peritoneum that extends from left colic flexure to the thoracic diaphragm opposite the 10th and 11th ribs; passes inferior to and supports spleen
Ligaments of the liver
•Falciform – anterior abdominal wall to liver; has round ligament at end
•Coronary – superior surface of liver to inferior surface of diaphragm
•Triangular – lateral extensions of the coronary ligaments
Nerves the supply the skin of the anterior abdominal wall (don't forget to study the course of nerve supply in Netter's)
•Ventral rami of T7-T12
•T10 supplies umbilicus****
•T12 is subcostal nerve serves hypogastric region
•Ventral rami of L1
•Iliohypogastric nerve
•Ilioinguinal nerve
Intraperitoneal organs
invested by visceral peritoneum on all surfaces and are therefore mobile; stomach, duodenum, jejunum, ileum, cecum, vermiform appendix, transverse colon, sigmoid colon, liver, gallbladder, spleen
Retroperitoneal organs
•Primary – covered by visceral peritoneum on their anterior surface; are immobile; rectum, kidneys, adrenal glands, urinary bladder, ureters, major blood vessels (aorta and IVC), prostate and vagina
•Secondary – developed with a mesentery but during development the organs were forced against the posterior abdominal wall and are covered by visceral peritoneum, renamed parietal peritoneum; duodenum (2-4 parts), ascending colon, descending colon, pancreas
Esophagus - anatomy
muscular tube posterior to the trachea (10 in long) from C6 to T10.
Allows passage of food from pharynx to stomach. It is retroperitoneal within the abdomen.
•Muscle: outer longitudinal and an inner circular layers
•Proximal 1/3 and middle 1/3 – skeletal and smooth muscle
•Distal 1/3 – smooth muscle only
•Inferior esophageal sphincter (cardiac or gastroexophageal sphincter) is not an anatomical sphincter (it is formed by the diaphragmatic musculature at the esophageal hiatus) and prevents reflux of gastric contents into the esophagus.
•Circular muscle fibers are under control of hormones (gastrin released by enteroendocrine cells relaxes this and constricts the pyloric sphincter) and vagus)
Esophagus - blood supply and venous drainage
•Arterial Supply
•Abdominal part is left gastric artery (from celiac trunk) and left inferior phrenic artery (from abdominal aorta)
•Venous drainage
•Form a submucosal venous plexus at distal end
•Drain into tributaries of azygos system and portal venous system
•Represents anastomosis between portal vein and caval circulations (azygos and superior vena cava)
Esophageal varices
•Enlarges esophageal veins in the submucosa of the esophagus
•Veins become enlarged due to increased pressure in the portal vein
•If ruptured, it can result in massive bleeding and vomiting of blood
Esophageal constriction sites
•Anatomical can be a site of foreign body obstruction or esophageal cancer
•Union with pharynx (C6)
•At aortic arch (T4)
•Site of crossing of left main bronchus (T5)
•Esophageal hiatus (T10)
Barrett's esophagus
•GERD may lead to this
•Esophageal lining is replaced by tissue similar to that found in the stomach (intestinal metaplasia)
•Tongues of Barrett’s are the darker areas present in the endoscopic view
•Marked by the presence of simple columnar epithelium instead of the stratified squamous non-keratinized epithelium that is more able to withstand the erosive action of that gastric secretions
•Increased risk of adenocarcinoma
Parts of the stomach
•Cardia surrounds the cardiac orifice (which lies posterior to the 6th left costal cartilage)
•Fundus extends to left from cardiac notch (posterior to 5th left intercostal space in the midclavicular plane)
•Body is the largest segment and contains a majority of fundic (gastric) glands
•Pyloric antrum is the wide part of the pyloric part of the stomach
•Pyloric canal is narrow and leads to pylorus
•Pyloric sphincter is found at the pylorus
•Pyloric orifice leads to first part of duodenum (lies at level of 9th costal cartilage near midline)
•Pylorus lies on right side and located near L2 vertebrae
•Greater curvature – begins at 6th left rib and passes inferiorly to the 10th left costal cartilage, turns medially to reach the pyloric antrum
•Lesser curvature – extends from right side of cardia to pyloris
•Angular notch is junction of lesser curvature and pyloric canal
•Greater omentum
•Gastrocolic ligament
•Gastrosplenic ligament
•Gastrophrenic ligament
•Lesser omentum – both ligaments are continuous parts; related to the foramen of Winslow that opens into lesser sac or omental bursa
•Hepatogastric ligament – membranous transparent portion
•Hepatoduodenal ligament – thickening free-edge portion of lesser omentum that conducts the portal triad
•Portal triad – consists of the common bile duct, hepatic artery proper and hepatic portal vein
Internal features of the stomach
•Cardiac orifice is the opening from the esophagus
•Pyloric orifice is the opening to the duodenum
•Rugae (plicae gastricae) are longitudinal coarse folds of gastric mucosa of the stomach. The groove channels between these folds are called gastric canals.
•Gastric pits are indentions in the stomach that are entrances to the gastric glands. Deeper in the pyloris than in the other parts of the stomach. Has about 3.4 million pits.
Stomach - arterial supply
•Lesser curvature – left gastric artery (from celiac trunk), right gastric artery (from hepatic artery proper which is from the common hepatic artery which is from the celiac trunk)
•Greater curvature – left gastroepiploic artery (from the splenic artery) and the right gastroepipolic artery (from the gastroduodenal artery from the common hepatic artery from the celiac trunk)
•Most frequent direct branches from celiac trunk = left gastric, splenic, common hepatic
Stomach - venous drainage
•Lesser curvature – left and right gastric veins > portal vein
•Greater curvature – short gastric veins and left gastroepiploic vein (both from the splenic vein)
•Right gastroepiploic vein empties into the superior mesenteric vein
•Splenic vein unites with superior mesenteric vein to form the hepatic portal vein
•Portal venous system
•Found posterior to head of pancreas
•Drains blood from the GI tract, spleen and pancreas to the liver
•Inferior mesenteric vein usually drains into splenic vein (also may drain into portal vein or superior mesenteric vein)
•Collateral venous circulation – portal obstruction in liver is relieved mainly by the several anastomoses – left gastric veins anastomose with esophageal veins that drain into the azygos system
•Superior rectal vein anastomoses with middle and inferior rectal veins that drain into the internal iliac veins that drain into the common iliac veins that will continue cranially to the inferior vena cava
•Portal systemic anastomosis – paraumbilical veins with thoracoepigastric veins within the abdominal wall, and retroperitoneal veins with veins of colon and bare area of liver. A patent ductus venosus shunts blood from the left branch of portal vein to the inferior vena cava. These provide collateral circulation during portal hypertension or obstruction.
Stomach - lymphatics
•Gastric nodes – found in a lesser curvature of the stomach
•Gastroepiploic nodes – (right and left) round at greater curvature of the stomach
•Efferent vessels join splenic, superior, pancreatic, pyloric and pancreaticoduodenal nodes
•All three nodal complexes accompany the large arteries to the celiac lymph nodes
Stomach - nerve supply
•PNS supply to stomach is via the anterior and posterior vagal trunks of the left and right vagus nerves, respectively (nerves enter abdomen through esophageal hiatus)
•SNS supply to stomach via T6-T9 and greater splanchnic nerve
•Celiac plexus consists of celiac ganglia and PNS fibers from anterior and posterior vagal trunks
Duodenum - structure/key anatomical features. Different parts of duodenum, ligament of Treitz, mesentery, duodenal papilla
•Is the first/shortest part of small intestine.
•It is the widest and most fixed part of the small intestine.
•It begins at the pylorus on right and ends at duodenojejunal junction of left.
•Superior part is about 2 inches and lies anterolateral to the body of L1. Found at the right lobe of the liver.
•Descending part is 3-4 inches in length and runs inferiorly along right side of L1 to L3 then curves around head of pancreas to right and parallel of inferior vena cava. Anterior to this segment is the transverse colon, and entering posterior is the common bile duct and major pancreatic duct.
•Horizontal part is about 3 inches long and crosses anterior to the inferior vena cava and abdominal aorta and posterior to the superior mesenteric artery and vein at L3.
•Ascending part is 2 inches in length and begins at the left of L3 vertebrae and rises superiorly to L2. It passes left of the aorta to reach inferior border of the body of the pancreas. This part joins with the jejunum.
•Ligament of Treitz is a fibromuscular band that connects the duodenojejunal flexure to the right crus of the diaphragm. This can be used to distinguish upper and lower GI tract
•Plicae circulares – circular valves of Kerckring are folds that increase the absorptive capacity of the duodenum.
•Major duodenal papilla drains bile and pancreatic enzymes (minor duodenal papilla). Demarcates junction of embryonic foregut and midgut and contains the opening of the hepatopancreatic ampulla (major pancreatic duct and common bile duct).
•First 1 inch of the duodenum has a mesentery. The mesentery is a double layer or peritoneum (intraperitoneal). Distal 1 inch of superior part and the rest of the duodenum has no mesentery and is retroperitoneal.
Duodenum - arterial supply
•Proximal 1st and 2nd part is gastroduodenal artery (branch of common hepatic artery which is from the celiac trunk) and its branches, the anterior and posterior superior pancreaticoduodunal arteries.
•3rd and 4th part of the duodenum are supplied by branches of the inferior pancreaticoduodenal artery (which branches from superior mesenteric artery). The superior mesenteric artery supplies most of the alimentary canal to the left colic (splenic flexure)
Duodenum - venous drainage
•Follow the arteries and drain into the superior mesenteric vein ultimately into the hepatic portal vein
Duodenum - nerve supply
•PNS is derived from anterior and posterior vagal trunks
•SNS is derived from greater and lesser splanchnic nerves via the celiac and superior mesenteric plexuses
Jejunum - anatomical features
•8 feet in length, larger in diameter than ilium (1-1.5 inches).
•Deep red in color. Highly vascularized and have long vasa rectae.
•Arcades have only a few large loops.
•The level of fat in the mesentery is less than the ileum. It is somewhat transparent.
•It has a large and tall circular fold, but few lymph nodes.
•Begins at the duodenojejunal junction.
Ileum - anatomical features
•12 feet in length, has a smaller diameter of about 1 inch.
•Pink in color. Less vascularized and has shorter vasa rectae
•Arcades have many short loops.
•The mesentery has more fat than the jejunum, thus is not transparent.
•Abundant lymph nodes.
•The ileum ends at the ileocecal junction.
Arterial supply to the jejunum and ileum
•Superior mesenteric artery supply both
•These vessels run within the layers of peritoneum within the mesentery
•Unite to form loop or arches caller arterial arcades.
•Arcades branch to straight arteries (vasa recta) that form windows
Venous drainage of jejumum and ileum
•Veins drain into superior mesenteric vein which lies to the right of the superior mesenteric artery
•Vessel ends posterior to the neck of the pancreas and usually unites with the splenic vein to for the hepatic portal vein
Innervation of jejumum and ileum
•SNS fibers originate at T8-T10
•Nerves connect to superior mesenteric nerve plexus through sympathetic trunk and the greater, lesser, and least splanchinic nerves. These nerves synapse with the celiac and superior mesenteric ganglia.
•PNS originate from the posterior vagal trunk
•Synapse with neurons in the myenteric plexus of Auerbach (muscle) and submucosal plexus of Meissner (glands) within the intestinal wall.
Duodenal ulcer
most commonly affects the proximal half of first part of the duodenum (duodenal cap or ampulla). The ulcer can perforate posterior and erode into the gastroduodenal artery resulting in a hemorrhage. An anterior perforation can result in peritonitis (an inflammation of the peritoneum) similar to a stomach ulcer.
Cecum - anatomy, artery, veins, lymph
blind pouch that is the first part of large intestine. The cecum is intraperitoneal but has no mesentery. Ilium enters medially and obliquely and forms ileal orifice.
•Artery – ileocolic artery (superior mesenteric artery)
•Veins – ileocolic vein drain into superior mesenteric vein
•Lymph – ileocolic lymph nodes into the superior mesenteric lymph nodes
Veriform appendix - features, artery, veins, lymph
a blind intestinal diverticulum. Its position is variable, but is most often retrocecal, posterior to cecum. McBurney’s point is the region 1/3 the way along an oblique line from umbilicus to right ASIS (site marks the point of tenderness in acute appendicitis and the base of the appendix). The mesoappendix is the mesentery of the vermiform appendix that contains the appendicular artery. The appendix has no tenia coli, but has 3 complete muscle layers. The 3 tenia coli converge at the base of the appendix.
•Artery – appendicular artery (branch of ileocolic artery)
•Veins – ileocolic vein drain into superior mesenteric vein
•Lymph – ileocolic lymph nodes into the superior mesenteric lymph nodes
Ascending colon - anatomy, artery, veins, lymph
extends from the cecum to right colic flexure. It is narrower than the cecum. It is retroperitoneal (although 25% of people have a short mesentery). It is separated from anterior abdominal wall by the greater omentum.
•Right lateral and medial paracolic gutters lie lateral and medial, respectively, to the ascending colon. (one of these doesn’t allow fluid to move to the pelvis… check it)
•Artery – ileocolic and right colic arteries (both from SMA)
•Veins – ileocolic and right colic veins drain into the superior mesenteric vein
•Lymph – lymph vessels that pass to epicolic and paracolic lymph nodes then ileocolic and right colic lymph nodes, then to superior mesenteric nodes
Transverse colon - anatomy, artery, veins, lymph
intraperitoneal and extends from right to left colic flexure. Left colic flexure is usually more superior than the right colic flexure and lies anterior to the left kidney. Mesentery is called the transverse mesocolon. Largest and most mobile part of large intestine.
•Artery - Right 2/3 is middle colic artery (SMA)
•Artery - Left 1/3 is left colic artery (inferior mesenteric artery)
•Vein – middle colic and left colic veins drains into superior and inferior mesenteric veins
•Lymph – drains to middle colic lymph that drains to the superior mesenteric lymph
Descending colon
extends from the left colic flexure to sigmoid colon in iliac fossa. Retroperitoneal.
•Left lateral and medial paracolic gutters lie lateral and medial to descending colon. All will allow fluid to pass to pelvis
•Artery – left colic artery (inferior mesenteric artery)
•Veins – drains into inferior mesenteric vein via left colic vein
•Lymph – epicolic and paracolic lymph nodes then to the inferior mesenteric lymph
Sigmoid colon
S-shaped loop that is variable in length that extends from the descending to rectum, from iliac fossa to S3. Termination of teniae coli markes the rectosigmoid junction. Usually has a long mesentery called sigmoid mesocolon and moves freely.
•Artery – 2-3 sigmoid arteries (inferior mesenteric artery)
•Vein – inferior mesenteric vein via sigmoid veins
•Lymph – epicolic and paracolic lymph nodes then to the inferior mesenteric lymph
fixed terminal part of the large intestine that is continuous with the sigmoid colon at S3. Junction of these two organs occurs at lower end of mesentery of sigmoid colon. Continuous with anal canal.
•Artery – superior rectal artery (continuation of inferior mesenteric artery which anastomoses with middle and inferior rectal arteries)
•Artery – middle rectal artery (branch of internal iliac artery)
•Artery – inferior rectal artery (branch of internal pudendal artery)
•Vein – rectum drains via superior rectal vein into the inferior mesenteric vein, the middle rectal vein into the internal iliac vein, and inferior rectal vein, into the internal pudendal vein
Features of the large intestine
•Possess teniae coli which are 3 longitudinal bands that represent the outer longitudinal muscle layer of the large intestine. Are not found in the vermiform appendix or rectum, thus both have complete muscle layers. These bands meet at the root of the appendix.
•Right colic flexure – between the right segment of the transverse colon and the ascending colon (L2)
•Left colic flexure – found at junction of left lateral segment of the transverse colon and the descending colon (T12)
•Haustrae are sacculations that form due to shorter teniae as compared with length of the colon
•Appendices epiploicae are fat tags/adipose that extend from the colon
•Transverse mesocolon is the mesentery of the large intestine
Abdominal aorta
•Continuation of thoracic aorta after passing through the aortic hiatus of diaphragm
•Three unpaired branches are derived from vessel.
•Celiac trunk supplies foregut (stomach to major duodenal papilla of duodenum)
•Superior mesenteric artery supplies midgut (major duodenal papilla to right 2/3 of transverse colon)
•Inferior mesenteric artery supplies hindgut (extends from left 1/3 of transverse colon to rectum
Innervation of the large intestine - SNS and PNS
•Thoracolumbar outflow from the spinal cord
•Preganglionic sympathetic fibers include
•Greater splanchnic – T5-9 supplies foregut
•Lesser splanchnic – T10-11 supplies midgut
•Least splanchnic – T12 supplies renal ganglia
•Lumbar splanchnic – L1-2 supplies hindgut
•Include celiac and superior and inferior mesenteric ganglia
•Postganglionic sympathetic fibers supply the mesentery and viscera
•Vagus nerve supply cecum to transverse colon
•Pelvic splanchnic nerves supply descending to rectum
•Craniosacral outflow from spinal cord
•Preganglionic parasympathetic fibers include vagus (foregut and midgut) and pelvic splanchnic nerve (hindgut)
•Parasympathetic ganglie are found in walls of viscera that include the myenteric plexus and submucosa plexus.
•Postganglionic parasympathetic fibers are very short
• The spleen is a mobile, ovoid lymphatic organ that is normally about 5 inches long and 3 inches wide
• This lymphoid organ is intraperitoneal in left upper quadrant of abdomen- contains T cells and macrophages
• At the hilum, the splenic vessels enter and leave the spleen
• The spleen is located between the left 9-11th ribs and separated by the diaphragm from costodiaphragmatic recess
• The spleen rests on left colic flexure (“splenic flexure”)
• The spleen is associated with the greater curvature and left kidney
• The hilum is associated with the tail of the pancreas
• The spleen makes up the left boundary of the omental bursa or lesser sac
Spleen - blood supply
•The spleen is supplied by the splenic artery that is the largest branch of the celiac trunk
•The splenic artery takes a very tortuous course posterior to the omental bursa, anterior of the left kidney, and along the superior border of the pancreas
•About 5 branches of the splenic artery enter the spleen
Spleen - venous drainage
The splenic vein exits the spleen at the hilum
oInferior of the splenic artery
•The inferior mesenteric vein normally drains into the splenic vein
•The splenic vein then merges with the superior mesenteric vein to form the hepatic portal vein
•The pancreas is an elongated gland that is retroperitoneal
•This gland extends transversely across the posterior abdominal wall lying posterior to the stomach
•It is found between duodenum (right) and spleen (left)
•The root of the transverse mesocolon lies on anterior margin of the pancreas
•The pancreas produces exocrine secretion, pancreatic juices, from the acinar cells that drains into the duodenum via ducts
•This organ also produces endocrine secretions, including glucagon and insulin, from the pancreatic islets of Langerhans that enter the bloodstream
Pancreas - ducts
Pancreatic Ducts
•Major Pancreatic Duct (of Wirsung) begins in tail of pancreas and runs through the parenchyma of the gland to the head and merges with the common bile duct
•Minor or accessory pancreatic duct (of Santorini) opens into minor duodenal papilla
Common Bile Duct
•The common bile duct either crosses the head of pancreas, or is embedded within the pancreas
•This duct unites with pancreatic duct to form the hepatopancreatic ampulla (of Vater).
•The papilla contains hepatopancreatic sphincter (of Oddi)
•The ampulla opens into the duodenum as the major duodenal papilla
Pancreas - vasculature
•The tail, body and neck of the pancreas are supplied by the branches of the splenic artery including the dorsal pancreatic artery, greater pancreatic artery and artery to the tail of pancreas from the splenic artery.
•The head of the pancreas is supplied by the anterior and posterior superior pancreaticoduodenal arteries which branch from the gastroduodenal artery
•The anterior and posterior inferior pancreaticoduodenal arteries which branch from the inferior pancreaticoduodenal artery from the superior mesenteric artery anastomose with the anterior and posterior superior pancreaticoduodenal arteries
•Veins that drain the pancreas are tributaries to the splenic and superior mesenteric vein
•The liver is the largest organ in the body (1500g), excluding the skin
•The liver is separated from pleura, lungs, pericardium and heart by the diaphragm
•The liver stores glycogen and synthesizes and secretes bile along with other metabolic activities
•The porta hepatis provides passage of blood vessels, bile ducts, and nerves at hilum
•The inferior vena cava lies superior and the gall bladder lies inferior
•Ligamentum venosum is the obliterated ductus venosus of the fetus
oThis vessel shunts blood from portal vein to inferior vena cava in fetus
•Ligamentum teres hepatis or round ligament of liver is obliterated umbilical vein
Surfaces of the liver
•The diaphragmatic surface of the liver is anterior, superior and posterior
•The visceral surface of the liver is covered with peritoneum except at bed of the gall bladder and porta hepatis (hilum of the liver)
•The bare area of the liver is still covered by the Glisson’s capsule which is fibrous capsule that covers the liver
Ligaments of the liver
•Falciform ligament contains the round ligament of the liver
•The right extremity of the coronary ligament forms the right triangular ligament and the left part forms left triangular ligament
•Peritoneal layers forming the coronary ligaments are widely dispersed and forms the bare area of the liver which is devoid of peritoneum
•The lesser omentum consists of the hepatogastric ligament and hepatoduodenal ligament
•Ligamentum venosum is the obliterated ductus venosus of the fetus. This vessel shunts blood from portal vein to IVC in fetus
•Ligamentum teres hepatis or round ligament of liver is the obliterated umbilical vein
Lobes of the liver
The classical lobes are divided by falciform ligament into right lobe consisting of the right lobe, quadrate lobe, and caudate lobe, and the left lobe
•Visualized posterior, the liver is divided into right and left lobes by the fissure of the ligamentum teres and ligamentum venosum
•The functional lobes are based on blood supply and bile drainage
•The functional right lobe includes the right lobe and casudate process of caudate lobe
•The functional left lobe consists of the left lobe, quadrate lobe, caudate lobe (except caudate process)
•The functional lobes are important when considering resection of the liver
Bile drainage
•The right and left hepatic ducts drain bile from the liver
•The common hepatic duct is formed by the union of right and left hepatic ducts
•The common bile duct formed by the union of the common hepatic duct and the cystic duct, that drains the gall bladder
•The hepatopancreatic ampulla (ampulla of Vater) form the union of the common bile duct and major pancreatic duct
•The hepatopancreatic ampulla opens into major duodenal papilla in the second segment of the duodenum
Relations of the common bile duct
•The hepatoduodenal ligament forms the anterior border of the epiploic foramen (of Winslow)
•The common bile duct is located to the right and superior
•The proper hepatic artery is located to the left
•The portal vein is located posterior
Liver - vasculature
•The liver receives blood from the hepatic portal vein (75%), which is poorly oxygenated, but the nutrient-rich blood from the gastrointestinal tract
•Oxygenated blood is derived from the hepatic arteries (25%) which branch from the proper hepatic artery, a branch from the common hepatic artery, in turn a branch of the celiac trunk
•Proper hepatic artery divides into right and left hepatic arteries at porta hepatis
Gall bladder and cystic duct
•The gallbladder is pear-shaped organ that lies in gallbladder fossa on visceral surface of the liver
•The fundus is the wide end that projects from inferior border of liver to the right 9th costal cartilage
•The body contacts the visceral surface of liver and superior part of duodenum
•The neck is narrow, tapered, and directed toward porta hepatis
•The neck makes an S-shaped bend to join the cystic duct
•The mucosa of the neck spirals into a fold to form the spiral valve that keeps the cystic duct open
•The cystic duct is about 4 cm in length that connects the neck of the gallbladder to the common hepatic duct
•The cystic duct joins the common hepatic duct to form the common bile duct
Hiatal hernia
•The gallbladder is pear-shaped organ that lies in gallbladder fossa on visceral surface of the liver
•The fundus is the wide end that projects from inferior border of liver to the right 9th costal cartilage
•The body contacts the visceral surface of liver and superior part of duodenum
•The neck is narrow, tapered, and directed toward porta hepatis
•The neck makes an S-shaped bend to join the cystic duct
•The mucosa of the neck spirals into a fold to form the spiral valve that keeps the cystic duct open
•The cystic duct is about 4 cm in length that connects the neck of the gallbladder to the common hepatic duct
•The cystic duct joins the common hepatic duct to form the common bile duct
Colonic diverticulosis
oAbout 10% of Americans over 40 years of age and 50% over 60 years suffer from colonic diverticulosis
oThis condition is an outpouching (sac) of intestinal wall of the colon
oThese sacs do not contain the entire layer of the intestinal wall
oThis condition is often asymptomatic but can include mild cramps, bloating, and constipation
oComplications of colonic diverticulosis include bleeding, infections, perforations or tears, or blockages
oThis condition is most common descending colon or sigmoid colon
Bowel obstruction: Volvulus
oA twisting of a bowel loop may cause constriction of the vascular supply to organs of the GI tract
oThis condition most often affects the small intestine more than the large intestine
oThe sigmoid colon is affected most if constriction lies in the large bowel
oBowel obstruction is often associated with dietary habits, perhaps a bulky vegetable diet
Cirrhosis of the liver
oCirrhosis of the liver is characterized by diffuse fibrosis parenchymal nodular regeneration and disturbed hepatic architecture
oProgressive fibrosis disrupts portal flow and causes portal hypertension
oThe most frequent causes of cirrhosis include alcoholic liver disease (60-70%), viral hepatitis (10%), and genetic hemochromatosis (5%).
Meckel's Diverticulum
•Meckel’s diverticulum is a remnant of the vitelline duct, which is the proximal part of the yolk stalk that normally regresses between the 5th and 8th week of life
•A true diverticulum contains all layers of the intestinal wall unlike diverticulosis
•This condition may appear in various stages of regression as a short finger-like projection, fibrous cord, may remain patent creating an umbilico-intestinal fistula or may contain a sinus or cyst
•For this disorder, a rule of 2s applies
oMeckel’s diverticulum is present in 2-3% of infants
oIt is about 1-2 inches in length
oIt appears ~2-3 feet proximal to ileocecal junction
oThe mucosal lining is similar to that of the ileum, but may contain islands of 2 types of tissues either gastric or pancreatic mucosa
oThe 2 clinical manifestations include intestinal obstruction or GI bleeding
•This condition could mimic appendicitis presenting as periumbilical pain which localizes to the right lower quadrant
•Complications include ulcerations, inflammation, torsion with or without strangulation, and herniation
Regional enteritis
•Regional enteritis is also known as Crohn’s disease
•It is a chronic inflammation often affecting the terminal ileum and possibly the colon
•Segments affected are often separated by normal segments called skip lesions
•This condition represents an increased cancer risk
Hirschprung's (megacolon)
•Hirschsprung’s disease is a condition in which a portion of colon is dilated (megacolon) due to absence of autonomic ganglia (parasympathetic) in the intestinal wall distal to the dilated segment
•The absence of ganglia is due to arrest of migration of neural crest cells
•Dilation is due to failure of peristalsis in the aganglionic segment
•One in every 5,000 live births are affected by this disorder
•It is the most common cause of neonatal obstruction of the colon (33%)
•Males are affected more than females (5:1)
•This disorder most often affects the sigmoid colon and rectum
•The aganglionic segment lacks submucosal plexus of Meissner and myenteric plexus of Auerbach
•It presents as abdominal enlargement and constipation in neonates
•The appendix is variable in position, but is most frequently retrocecal (64%) and pelvic (32%). It can also rest retrocolic and subcecal
•An appendicitis is in inflammation of vermiform appendix
•The opening of appendix into the cecum may become blocked by build-up of thick mucus, hardened stool, or enlarged lymphoid tissues
•The person will suffer diffuse, poorly localized pain initially that moves to the right inguinal area due to involvement of the parietal peritoneum
•Other early symptoms include nausea and vomiting
**Appendix on practical - look for lymphoid tissue!**
Manifestations of liver disease
oJaundice is yellowing of the integument and sclera
oAscites is an accumulation of serous fluid in the abdominal cavity
oEnlargement of abdomen
oCaput medusa is the presence of varicose veins radiating from the umbilicus
oSpider angiomas is a type angioma found below the skin’s surface, often containing a central red spot and reddish extensions which radiate outwards like a spider’s web
They are benign and present in 10-15% of healthy adults and young children
Most are a result of liver disease
They are due to failure of the muscle surrounding a cutaneous arteriole
The central red dot is dilated arteriole and the red “spider legs” are small veins carrying away the freely-flowing blood
oEsophageal varices
oBleeding tendencies
oTesticular atrophy
Portal HTN
oHematemesis is fresh bleeding from esophageal varices which are enlarged esophageal veins that drain into the left gastric and azygos veins
oCaput medusa is enlarged paraumbilical veins that drain into the portal vein
oHematochezia is fresh bleeding from hemorrhoids, resulting from enlarged superior rectal veins as direct continuation of the inferior and middle rectal veins
oSplenomegaly is an enlargement of the spleen.
oIt is one of the four cardinal signs of hypersplenism, the other three being cytopenia, normal or hyperplastic bone marrow, and a response to splenectomy
oSplenomegaly is usually associated with increased workload, such as in hemolytic anemias that suggests that it is a response to hyperfunction
oSplenomegaly is associated with any disease process that envolves abnormal erythrocytes being destroyed in the spleen
oOther common causes include congestion due to portal hypertension and infiltration by leukemias and lymphomas
oAn enlarged spleen and caput medusa are important signs of portal hypertension
•Gallstones are also called cholelithiasis
•These concentrations consist of cholesterol (80%) as a crystalline cholesterol monohydrate
•Pigment stones (20%) are composed of bilirubin calcium salts
•Gallstones are commonly impacted in the hepatopancreatic ampulla, neck (Hartmann’s pouch) and in the common bile duct
•Gallstones may produce biliary colic or pain in the epigastric region
•Risk factors for gallstones include advanced age, obesity, female, rapid weight loss, estrogenic factors, and gallbladder stasis
Supporting users have an ad free experience!