Anatomy Of The Stomach & Duodenum (2024-2025) PDF

NATOMY DEPARTMENT A ANATOMY OF THE STOMACH & THE DUODENUM Dr. Wael Amin Nasr El-Din Associate Prof. of Anatomy CMHS – AGU (2024-2025) INTENDED LEARNING OUTCOMES At the end of the lecture, the students should be able to: State the location of the stomach....

NATOMY DEPARTMENT A ANATOMY OF THE STOMACH & THE DUODENUM Dr. Wael Amin Nasr El-Din Associate Prof. of Anatomy CMHS – AGU (2024-2025) INTENDED LEARNING OUTCOMES At the end of the lecture, the students should be able to: State the location of the stomach. Describe the shape and parts of the stomach. Discuss the relations of the stomach. Describe the blood supply, innervation and lymphatics of the stomach. Mention the parts of small intestine. Describe the location and parts of duodenum. Discuss the relations of the duodenum. Describe the blood supply, innervation and lymphatics of the duodenum. 1 Dr: Wael Amin  ABDOMINAL PLANES Left midclavicular line Right midclavicular line Median plane Right upper Left upper quadrant quadrant Transumbilical plane Epigastric region Right lower Left lower Left hypochondrium quadrant quadrant Right hypochondrium T12 L1 Transpyloric plane (L1) L2 Subcostal plane (L 3) L3 Umbilical region L4 Left lumbar region Right lumbar region L5 Intertubercular plane (L5) Right iliac region Left iliac region Hypogastric region 2 Dr: Wael Amin  ABDOMINAL PLANES ▪ Abdomen is divided into 4 regions by 2 planes; median plane and transumbilical planes: Right upper quadrant Left upper quadrant Right lower quadrant Left lower quadrant ▪ Abdomen is divided for descriptive purposes when examining and describing pathologies related to abdomen into 9 regions by 4 planes. ▪ Two horizontal planes: subcostal (L3) and intertubercular (L5) planes. ▪ Two vertical planes: right and left midclavicular lines. Right Epigastrium Left hypochondrium hypochondrium Right lumbar Umbilical Left lumbar Right iliac Hypogastrium Left iliac 3 Dr: Wael Amin  LOCATION OF THE STOMACH Left midclavicular line Right midclavicular line ▪ Is the most dilated part of GIT. ▪ Located in the abdomen; in left hypochondrium, epigastric and umbilical regions. hypochondrium Left ▪ Located at level of T10 - L3 Epigastric region Stomach vertebrae. Subcostal plane ▪ Its capacity in adult is about 2 liters. Umbilical region Intertubercular plane Stomach 4 Dr: Wael Amin  SHAPE OF THE STOMACH 1. J-shaped (more common): long axis is vertical. 2. Steer horn: long axis is horizontal. ▪ Shape of stomach is dynamic and depends on: 1. Degree of distension: empty stomach is more vertical. 2. Body built: more horizontal in short obese people. J- shaped stomach in thin tall person 3. Phase of respiration: more vertical in inspiration. 4. Position of the body: more vertical in standing position. 5 Dr: Wael Amin Steer horn- shaped stomach in short obese person EXTERNAL FEATURE OF THE STOMACH Cardiac notch ▪ 2 Orifices: 1. Cardiac orifice. Esophagus Fundus 2. Pyloric orifice. Cardiac orifice ▪ 2 Borders: Cardia 1. Greater curvature. Angular notch 2. Lesser curvature. Pyloric orifice Pylorus ▪ 2 Surfaces: Body 1. Anterior surface. 2. Posterior surface. ▪ 4 Parts: 1. Cardia. Duodenum 2. Fundus. 3. Body. 4. Pyloric part: ▪ 2 Notches: ▪ Pyloric part is formed of 3 parts: 1. Cardiac notch. A. Pyloric antrum. 2. Angular notch. B. Pyloric canal. 6 Dr: Wael Amin C. Pylorus.  1. ORIFICES OF THE STOMACH Median plane 1. Cardiac orifice: (more fixed end) Esophagus ▪ Lies at the junction of stomach with Cardiac orifice esophagus. ▪ Lies behind left 6th costal cartilage 2-4 cm from the median plane at the level of T10 or T11 vertebra. ▪ Gastroesophageal sphincter: ▪ It is a physiological sphincter. Lower end of esophagus ▪ Consists of smooth muscle fibers of right crus of diaphragm which encircle lower end of esophagus. ▪ Function: prevents gastric reflux. 7 Dr: Wael Amin Right crus of the diaphragm which encircle the lower end of the esophagus  1. ORIFICES OF THE STOMACH Median plane 2. Pyloric orifice: (less fixed end) ▪ Lies at junction of stomach with duodenum. ▪ Lies at the transpyloric plane (L1), 1.25 cm to Pyloric orifice the right of the median plane. Transpyloric plane (L1) ▪ Its position is indicated by: 1. Circular groove (pyloric constriction). Duodenum 2. Prepyloric vein of Mayo. ❖ Because this vein is clear, surgeons use it for identifying the pylorus. ▪ Pyloric sphincter: is thick anatomical sphincter. Pyloric constriction Pyloric sphincter Prepyloric vein of Mayo 8 Dr: Wael Amin  2. BORDERS OF THE STOMACH Lesser omentum Angular notchCardiac orifice 1. Lesser curvature: (right concave Cardiac notch border). ▪ Extends from cardiac orifice to the Liver pylorus and has angular notch. ▪ Attached to liver by lesser omentum. 2. Greater curvature: (left convex border). ▪ Extends from cardiac notch to pylorus. Pylorus Greater omentum ▪ Upper part is attached to diaphragm Gastrosplenic ligament Gastrophrenic ligament by gastrosphrenic ligament. Stomach turned up ▪ Middle part is attached to spleen by Gastrosplenic gastrosplenic ligament. ligament ▪ Lower part is attached to transverse colon by the greater omentum. Transverse colon 9 Dr: Wael Amin  3. PARTS OF THE STOMACH Cardia 1. Cardia: Fundus ▪ Area surrounding cardiac orifice. Cardiac opening Pylorus 2. Fundus: Pyloric opening Angular notch ▪ Dome-shaped, located to the left of the cardiac orifice, it reaches to left 5th intercostal space. Body ▪ Usually full of gas and appears black in X-Ray. 3. Body: ▪ Extends from the level of the fundus to the level of angular notch. Cardiac opening 4. Pyloric part: I. Pyloric antrum: (widest part) extends from angular notch to the pyloric canal. Pyloric sphincter II. Pyloric canal: narrow part distal to antrum. Angular notch III. Pylorus: the distal part, has thick muscular Body Pyloric end called pyloric sphincter. canal Pyloric ▪ Lining gastric mucosa showed folds called antrum gastric rugae. 10 Dr: Wael Amin Gastric rugae (folds)  RELATIONS OF THE STOMACH 1. Anterior relation: ▪ Anterior abdominal wall. ▪ Left costal margin. ▪ Left pleura and lung. Left lobe of the liver ▪ Diaphragm. Left costal ▪ Left lobe of the liver. cartilage Stomach 11 Dr: Wael Amin  RELATIONS OF THE STOMACH Left crus of diaphragm 2. Posterior relation: (stomach Left suprarenal gland bed) which include: ▪ Left crus of the diaphragm. ▪ Left suprarenal gland. ▪ Upper part of left kidney. ▪ Splenic artery. Pylorus ▪ Pancreas. ▪ Transverse mesocolon. ▪ Transverse colon. Splenic artery and vein ▪ Spleen. Stomach is totally covered by ❖ Stomach is separated from these peritoneum except a small part structures by the lesser sac. in its posterior surface close to cardiac orifice (bare area of the stomach) that is related to left 12 Dr: Wael Amin crus of diaphragm.  CLINICAL NOTES Perforating ulcer in the posterior wall of the stomach: May result in: 1. Peritonitis initially in the lesser sac. 2. Referred back pain due to invasion of the pancreas Pylorus resulting in pancreatitis. 3. Erosion of splenic artery resulting in severe peritoneal Splenic artery and vein hemorrhage. 13 Dr: Wael Amin  ARTERIAL SUPPLY OF STOMACH Left gastric artery ▪ Are branches from celiac Esophageal branch of left gastric artery trunk (branch of abdominal Coeliac trunk aorta arising at level of Common hepatic artery T12). 1. Left gastric artery: branch Right gastric of celiac trunk. artery ▪ Passes upwards to reach Hepatic artery proper esophagus and then descends along lesser Abdominal aorta curvature. ▪ Supplies lower third of 2. Right gastric artery: branch of hepatic esophagus and upper right artery. part of stomach. ▪ It runs to left along lesser curvature. ▪ Supplies lower right part of stomach. 14 Dr: Wael Amin  ARTERIAL SUPPLY OF STOMACH Esophageal branch of left gastric artery 3. Short gastric arteries: Left gastric artery Posterior gastric ▪ Arise from splenic artery. Coeliac trunk Splenic artery artery ▪ Supplies fundus of stomach. Common hepatic artery 4. Left gastro-omental artery: Right gastric ▪ Arises from splenic artery at artery Hepatic artery hilum of spleen. proper Gastroduodenal ▪ Supplies stomach along upper artery part of greater curvature. 5. Right gastro-omental artery: Short gastric arteries arises from gastroduodenal Left gastroepiploic artery. (gastroomental) artery ▪ Supplies stomach along lower Right gastroepiploic (gastroomental) artery part of greater curvature. 6. Posterior gastric artery: branch of splenic artery (may be absent). ▪ Supplies back of fundus and upper 15 Dr: Wael Amin part of body of stomach. VENOUS DRAINAGE OF STOMACH ▪ Veins of the stomach drain Splenic vein Short gastric vein into portal circulation. 1. Left and right gastric veins Left gastric vein drain directly into hepatic Right gastric vein portal vein. Portal vein 2. Short gastric veins and left gastroepiploic veins drain Left gastroepiploic vein into splenic vein. 3. Right gastroepiploic vein drains into superior Right gastroepiploic vein Superior mesentric vein mesenteric vein. 16 Dr: Wael Amin LYMPHATIC DRAINAGE OF STOMACH ▪ Anterior and posterior surface Celiac lymph Gastric lymph node Pancreaticosplenic lymph node of stomach drain into gastric node and gastro-omental lymph nodes (LNs). Superior and ▪ Efferent vessels drain into inferior pyloric lymph node pancreaticosplenic, pyloric and pancreaticoduodenal LNs. ▪ All the lymph ultimately drains into celiac LNs. Pancreaticoduodenal lymph node Gastro-omental lymph node 17 Dr: Wael Amin  NERVE SUPPLY OF STOMACH Anterior vagal trunk 1. Parasympathetic: (Motor and secretomotor) A. Anterior vagal trunk: formed from left vagus nerve to supply anterior surface of stomach. B. Posterior vagal trunk: formed from right vagus nerve and supply posterior surface of stomach. 2. Sympathetic: from greater splanchnic nerves (T6-T9 segments of spinal cord) via celiac plexus and carries pain fibers and is motor to pyloric Posterior vagal trunk sphincter. Celiac branch 18 Dr: Wael Amin Celiac plexus  ANATOMY OF THE DUODENUM 19 Dr: Wael Amin  POSITION OF THE SMALL INTESTINE ▪ Small intestine is the longest part of the GIT (about 6 meter long), occupying central and lower part of the abdomen. ▪ Surrounded by large intestine and covered anteriorly by greater omentum and anterior abdominal wall. ▪ Extends from pyloroduodenal junction to ileocecal junction. ▪ Divided into 3 parts: duodenum, jejunum and ileum. Pyloroduodenal junction Greater omentum Small Duodenum intestine Jejunum Ileocecal junction Ileum 20 Dr: Wael Amin  DUODENUM ▪ It is shortest, dilated and most fixed Pyloroduodenal junction proximal part of small intestine. ▪ Has C–shaped curve around head of pancreas. ▪ Begins at pyloric end of stomach, ½ inch to the right of median plane. ▪ Ends in acute angle at duodenojujenal flexure, one inch to the left of the median plane. Duodenojejunal flexure Duodenum 21 Dr: Wael Amin  PARTS OF THE DUODENUM ▪ Duodenum is 25 cm long and has 4 parts: 1st 1. 1st (superior) part: 5 cm long, lies opposite L1 vertebra. 2nd 2. 2nd (descending) part: 7-10 cm long, extends from L2-L3 vertebrae. 3. 3rd (horizontal) part: 6-8 cm long, lies at the level of L3 vertebra. 4th 4. 4th (ascending) part: 5 cm long, ascends 3rd from the level L3 to L2 vertebra. 1st L1 Duodenal cap or duodenal bulb 2nd (ampulla): is the smooth walled dilated first 2 cm of L2 1st part of duodenum. - Common site for duodenal ulcer. L3 22 Dr: Wael Amin 3rd PERITONEAL COVERINGS OF THE DUODENUM First 2 cm of the duodenum ▪ Duodenum is retroperitoneal and fixed to posterior abdominal wall EXCEPT: 1. First 2 cm is suspended by lesser omentum (above) and greater omentum (below). 2. Distal end is attached right crus of diaphragm by suspensory muscle of the duodenum (suspensory ligament of Treitz); a surgical landmark to Greater omentum discriminate between upper and lower GIT Right crus of diaphragm bleeding. Ligament of Treitz 23 Dr: Wael Amin Distal end of the duodenum  RELATIONS OF FIRST PART OF DUODENUM Quadrate lobe of the liver (turned up) ▪ Relations of last 3 cm of 1st part: A. Anteriorly: 1. Quadrate lobe of the liver. Gall bladder 2. Gall bladder. B. Posteriorly: 1. Bile duct. 2. Gastroduodenal artery. 3. Portal vein. Perforated duodenal ulcer: occurs In the first part and may affect liver and Bile duct gall bladder and may erode Portal vein gastroduodenal artery leading to severe peritoneal hemorrhage. Gastroduodenal artery 24 Dr: Wael Amin RELATIONS OF SECOND PART OF DUODENUM A. Anteriorly: 1. Upper part: right lobe of the liver. 2. Middle part: transverse colon. Right lobe of the 3. Lower part: loops of the jejunum. liver (cut) D. Posteriorly: Transverse 1. Right kidney. colon Loops of 2nd part of duodenum jejunum 2. Right renal vessels. 3. Right pelvis of the ureter. 4. Right psoas major muscle. Right kidney Right renal vessels Right ureteric pelvis Right psoas major 25 Dr: Wael Amin  RELATIONS OF THIRD PART OF DUODENUM Root of mesentery A. Anteriorly: Superior mesenteric vessels 1. Root of the mesentery. 2. Superior mesenteric vessels. B. Posteriorly: 1. Right ureter. 2. Right psoas major muscle. 3. Right gonadal vessels. 4. Inferior vena cava. 5. Abdominal aorta and origin of inferior mesenteric artery. IVC Right ureter Right gonadal vessels Abdominal Right psoas major aorta Inferior mesenteric 26 Dr: Wael Amin artery 26 RELATIONS OF FOURTH PART OF DUODENUM Coils of jejunum A. Anteriorly: ▪ Coils of jejunum. B. Posteriorly: 1. Left psoas major muscle. 2. Left sympathetic trunk. 3. Left renal vessels. 4. Left gonadal vessels. 5. Inferior mesenteric vein. Left sympathetic trunk 4th part of duodenum Renal artery Inferior mesenteric vein Left gonadal artery 27 Dr: Wael Amin STRUCTURES OPENING IN THE 2ND PART OF THE DUODENUM Bile duct Minor Main pancreatic duct 1. Bile duct unites with main duodenal papilla pancreatic duct forming hepatopancreatic ampulla (ampulla of Vater), Accessory pancreatic surrounded by sphincter duct of Oddi. Major duodenal papilla ▪ The ampulla opens in major Bile duct duodenal papilla. 2. Accessory pancreatic duct opens 1” above major duodenal papilla, in minor Main duodenal papilla. pancreatic duct Major duodenal 28 papilla Dr: Wael Amin Ampulla of Vater surrounded by sphincter of Oddi  BLOOD SUPPLY OF THE DUODENUM ▪ Arterial supply: 1. Upper 1/2: supraduodenal and superior pancreaticoduodenal artery, Gastroduodenal from gastroduodenal artery. artery Supraduodenal 2. Lower 1/2: inferior artery pancreaticoduodenal artery, from Superior pancreaticoduodenal superior mesenteric artery. artery ▪ Venous drainage: Inferior pancreaticoduodenal Superior mesenteric 1. Superior pancreaticoduodenal vein artery artery drains into portal vein. 2. Inferior pancreaticoduodenal vein drains into superior mesenteric vein. Portal vein The 2 different sources of blood supply because upper part is Superior pancreaticoduodenal developed from foregut while lower vein part from midgut, separated at Inferior opening of bile duct. 29 Superior Dr: Wael Amin pancreaticoduodenal vein mesenteric vein  ARTERIAL SUPPLY OF DUODENUM Supraduodenal artery Gastroduodenal artery Superior mesenteric artery: a branch of abdominal aorta arises at the level of L1 vertebra. Superior pancreaticoduodenal artery Superior mesenteric artery Inferior pancreaticoduodenal artery Arterial supply of the duodenum 30 Dr: Wael Amin LYMPHATIC DRAIAGE OF THE DUODENUM Celiac lymph nodes ▪ Drains into pancreatico- duodenal lymph nodes (LNs). ▪ Then drain into celiac and Hepatic lymph superior mesenteric LNs. nodes Pyloric lymph ▪ Some vessels drain into nodes pyloric and hepatic LNs. Superior mesenteric lymph nodes Pancreaticodudenal lymph nodes ▪ NERVE SUPPLY OF DUODENUM: Anterior & posterior vagal trunk ▪ Sympathetic (greater and lesser Coelic ganglion & plexus Sympathetic splanchnic nerves) and ganglia & trunk parasympathetic (vagus nerve) Superior mesenteric nerves from celiac superior ganglion & plexus mesenteric plexuses. 31 Dr: Wael Amin