abdominal esophagus & stomach.pdf

Esophagus (abdominal part) & Stomach Dr. Ahmed AL-Baghdadi  Anatomy Overview ❑ Upper GIT ▪ Aero- digestive pathway ✓ Mouth ✓ Pharynx ▪ Forgut ❑ Lower GIT ▪ Midgut ▪ Hindgut ❑ Accessory Organs Arterial supply of the GIT ...

Esophagus (abdominal part) & Stomach Dr. Ahmed AL-Baghdadi  Anatomy Overview ❑ Upper GIT ▪ Aero- digestive pathway ✓ Mouth ✓ Pharynx ▪ Forgut ❑ Lower GIT ▪ Midgut ▪ Hindgut ❑ Accessory Organs Arterial supply of the GIT  Esophagus  Fibromuscular tune  25cm  Upper third ✓ Striated muscle (Unique)  Lower two-third  Smooth muscle  Parts: 3 ✓Cervical : travels through the neck ✓Thoracic: located in thorax (superior & posterior mediastinum ✓Abdominal : shortest ✓only part of the esophagus covered with peritoneum.  Abdominal Esophagus Abdominal part of abdominal esophagus ❑ short abdominal part (1/2 inch long) ❑ extends from diaphragm to cardiac orifice of stomach, ❑ entering abdomen through an opening in right crus of diaphragm. At level of T10  Abdominal Esophagus Abdominal part of abdominal esophagus is related ❑ Anteriorly: ❑ to left vagus & posterior surface of left lobe of liver ❑ Posteriorly: ❑ to right vagus & left crus of diaphragm left crus  Abdominal Esophagus Abdominal part of abdominal esophagus is related ❑ Anteriorly: ❑ to left vagus & posterior surface of left lobe of liver ❑ Posteriorly: ❑ to right vagus & left crus of diaphragm left vagus  Lt vagus----anterior vagus Rt vagus ----posterior vagus ❑Vagus nerve responsible for parasympathetic innervation up to distal 1/3 of transverse colon  Esophagus  2 sphincters UES ✓ - formed by cricopharyngeus mm ✓ relax during swallowing to allow passage of food ✓ - Preventing air from entering into the esophagus during breathing LES (G-E or cardiac spincter) ✓ 3-5 cm ✓ high pressure zone at the lower part of the esophagus , detected by manometry ✓ NOT muscular sphincter  Abdominal Esophagus Abdominal part of esophagus Lower Oesophageal Sphincter (physiological sphincter) ▪ located in the gastro-oesophageal junction situated to the left of the T11 vertebra ▪ is marked by the change from oesophageal to gastric mucosa (Ora serrata OR Z- line). does not have any specific sphincteric muscle. Instead, a number of forces act to prevent gastro-esophageal reflux 1) valve like action of the acute gastro-oesophageal angle ( angle of His ). 2) abdominal part of the oesophagus is subjected to high positive intra-abdominal pressure 3) folds of mucosa present of upper end of stomach forming a plug to the lower end of the oesophagus 4) & 5) two mechanisms believed to have adequate antireflux barrier (IMPORTANT) 4) It shows a specialized area of circular smooth muscle, which possesses the physiological properties of the sphincter ✓. This muscle maintained under tonic contractions by the intramural plexuses of enteric nervous system 5) The muscle fibers of the right crus of the diaphragm, which surround the terminal portion of the esophagus provide external sphincter ✓ This barrier is lowered during swallowing & vomiting ✓ If the intra-gastric pressure rises sufficiently, the acidic contents of the stomach regurgitate into the lower end of the esophagus ✓ to be returned to stomach by reflex peristalsis ✓ The stratified squamous non-keratinized epithelium of the esophagus has ✓ no protective properties against gastric acid. This leadto reflux esophagitis, which causes burning pain behind the sternum, known as heartburn.  Abdominal Esophagus Abdominal part of abdominal esophagus Blood Supply ❑ are branches from left gastric artery & left inferior phrenic artery  Abdominal Esophagus Abdominal part of abdominal esophagus Blood Supply ❑ are branches from left gastric artery & left inferior phrenic artery  Abdominal Esophagus Venous drainage of lower part of esophagus has a mixed venous drainage via two routes: 1) To the portal circulation via left gastric vein 2) To the systemic circulation via the azygous vein. Anastomosis of these to veins form a submucosal venous plexus which is a porto-systemic anastomosis( connection between the portal and systemic venous systems  Sites of Portosystemic Anastomoses At the lower end of esophagus Around the umbilicus At the level of Pectinate line in the anal canal submucosal venous plexus  Abdominal Esophagus This submucosal venous plexus is dilated and tortuous in portal hypertension giving rise to esophageal varices. The rupture of the varices leads to vomiting of blood (hematemesis  Abdominal Esophagus Endoscopic feature of Lower Oesophageal Sphincter 3 endoscopic features Z- line, Smooth surface, Longitudinal fold(Ruguae) below Z line  Abdominal Esophagus What is Zigzag (Z-line)? Anatomical gastroesophageal junction (G-E) does not corresponding with histological G-E junction That is mean - Distal 2 cm of Esophagus is lined by a simple columnar epithelium with goblet cells instead of stratified squamous epithelium - This mucosal G-E junction seen macroscopically(endoscopically) as a zigzag line(z-line) 2cm above anatomical G-E junction - Stomach  Stomach LOCATION In upper left part of the abdomen occupying ✓ left hypochondriac ✓ epigastric ✓ umbilical Most of the stomach lies under cover of the left costal margin and lower ribs. SHAPE mostly “J” shaped. Its long axis passes ✓ downward, forward, and to the right It tapers from the fundus on the left of the median plane to the narrow pylorus slightly to the right of the median plane.  Stomach It usually partially overlying by the transverse colon near the left colic flexure. stomach Transverse colon  Stomach EXTERNAL FEATURES stomach presents the following external features: 1. Two ends: cardiac and pyloric. 2. Two curvatures: greater and lesser. 3. Two surfaces: anterior (anterosuperior) posterior (posteroinferior).  Stomach Lesser Curvature ✓ concave , forms shorter right border of the stomach. ✓Angular notch/incisura angularis, : most dependent part of this curvature, indicates the junction of the body and pyloric part. ✓ provides attachment to the lesser omentum. Greater Curvature ✓It is convex and forms the longer left border of the stomach. ✓provides attachment to the greater omentum, gastrosplenic, and gastrophrenic ligaments.  Stomach PARTS The stomach has four parts : 1. Cardiac part. 2. Fundus. 3. Body. 4. Pyloric part.  Stomach cardiac end : Pyloric end 1- It does not have an anatomical 1- It has an anatomical sphincter sphincter (only physiological). (thick circular muscle layer ). 2- It lies at the level of 2- It lie at the level of - left 7th c.c. - L1 vertebra ( trans-pyloric - 1 inch to left side of midline, plane ) - 45 cm from incisors, - 1 inch to right of midline. - 10 cm deep to ant. abdominal wall - It can be detected during operation by o pyloric constriction , oprepyloric vein of Mayo o feeling the thickened pyloric sphincter  Stomach Fundus part above the level of cardiac notch. normally filled with air in the erect posture, which is usually visible in a plain radiograph of the abdomen under the left dome of diaphragm. Superiorly, the fundus touches the left dome of the diaphragm and reaches the level of the left 5th intercostal space just below the nipple.  Stomach PYLORIC PART It extends from the angular notch to the gastroduodenal junction. It is divided into three parts: 1)pyloric antrum ❖ proximal wide part which is separated from the pyloric canal by an inconstant sulcus,( sulcus intermedius) present on the greater curvature 1)2) pyloric canal, ❖distal narrow and tubular part ❖ lies on the head and neck of the pancreas. 1)3) pyloric sphinctor. ❖ distal most and sphincter region of the pyloric canal. ❖circular muscle fibers are markedly thickened  Stomach RELATIONS 1) PERITONEAL RELATIONS ❖ stomach is covered by the peritoneum ❖ peritoneal folds extending from the lesser and greater curvatures of the stomach to other structures are as follows: a) Lesser omentum b) Greater omentum c) Gastrosplenic ligament d) Gastrophrenic ligament  Stomach RELATIONS 2) VISCERAL RELATIONS a) Relations of the anterior (anterosuperior) surface: ❖ Upper 2/3 ❖ On the right ✓ left lobe of the liver ✓ near the pylorus to the quadrate lobe of the liver. ❖ On left ✓ diaphragm ✓ rib cage ✓ Left pleura and lung ❖ lower part of this surface is related to ✓ anterior abdominal wall.  Stomach RELATIONS 2) VISCERAL RELATIONS b) Relations of the posterior (posteroinferior) surface: this surface is related to Stomach bed a number of structures on the posterior abdominal Wall related to stomach. These structures are: (1) Diaphragm. (2) Left kidney. (3) Left suprarenal gland. (4) Pancreas. (5) Transverse mesocolon. (6) Left colic flexure (splenic flexure of colon). (7) Splenic artery. (8) Spleen..  Stomach INTERIOR OF THE STOMACH stomach presents the following features : 1. Gastric folds/gastric Rugae: Longitudinal folds in the mucosa of an empty 2. Gastric pits: small depressions on the mucosal surface in which open the gastric glands. 3. Gastric canal : ✓ longitudinal furrow ✓ along lesser curvature ✓ forms due to firm attachment of the gastric mucosa to the underlying muscular layer, which does not have an oblique layer at this site. ✓ allows a rapid passage of swallowed liquids along the lesser curvature to the lower part before it spreads to the other parts of the stomach.  Stomach INTERIOR OF THE STOMACH Longitudinal folds in the mucosa (Rugae)  Stomach ARTERIAL SUPPLY o has rich arterial supply derived from the celiac trunk and its branches 1. Left gastric artery, a direct branch from the celiac trunk. 2. Right gastric artery, a branch of the common hepatic artery. 3. Left gastroepiploic artery, a branch of the splenic artery. 4. Right gastroepiploic artery, a branch of the gastroduodenal artery. 5. Short gastric arteries (five to seven in number), branches of the splenic artery..  Stomach VENOUS DRAINAGE The veins of the stomach correspond to the arteries and drain directly or indirectly into the portal vein. 1. Left gastric vein. drain directly into the portal vein. 2. Right gastric vein. 3. Left gastroepiploic vein. Drain into splenic vein 4. Short gastric veins.5. Right gastroepiploic vein drains into the superior mesenteric vein.  Stomach LYMPHATIC DRAINAGE knowledge of lymphatic drainage of the stomach is clinically very important because gastric cancer (carcinoma of stomach) spreads through the lymph vessels 1. The fundus and left half of the body drain in to the pancreaticosplenic nodes, 2. The upper part of the right half of body drains into the left gastric nodes. 3. The lower part of the right half of body drains into the right gastroepiploic nodes. 4. The pyloric region drains into pyloric, hepatic and left gastric nodes.  Stomach NERVE SUPPLY has both sympathetic and parasympathetic innervation sympathetic T6 to T10 spinal segments via greater splanchnic nerves through celiac and hepatic plexuses (a) vasomotor, (b) motor to pyloric sphincter, and inhibitory to the remaining gastric musculature, (c) serves as the chief pathway for pain sensations from the stomach. referred pain from the stomach is felt in the epigastrium in the T7 to T9 dermatomes parasympathetic ▪ derived directly from the vagus nerves (CN10 Anterior vagus Lt vagus Posterior vagus Rt vagus Vagal stimulation ✓ increases acid and enzymatic secretion ✓ decreases sphincter tone ✓ increases gastric motility  Stomach NERVE SUPPLY anterior gastric nerve(Lt vagus) 1) hepatic branch: supply liver &gallbladder 2) gastric branches: supply anterior surface - Supply acid &pepsin secreting area 3) Anterior nerve of Latarjet. - antral branches for pyloric antrum. posterior gastric nerve(Rt vagus) 1) celiac branches. 2) criminal nerve of Grassi for the supply of fundus. 1) gastric branches to the posterior surface of stomach. 3) posterior nerve of Latarjet, which give rise into antral branches ▪ Peptic ulcer due to high HCL secretion Note: - Failure to cut criminal nerve of grassi lead to recurrent ▪ Reduce secretion by cutting vagus nerve ulcer after selective vagotomy (Vagotomy) - Both latarjet(ant & post)(crows foot) innervate 1- Truncal vagotomy: antro-pyloric region, these branches are spared 2. Selective vagotomy: in highly selective vagotomy 3- High selective vagotomy:  Stomach Coeliac trunk artery of the foregut, Has three branchest 1) left gastric, 2) splenic 3) common hepatic arteries Supply ✓ gut from the lower part of the oesophagus down to the opening of the bile duct into the duodenum, ✓ foregut derivatives (the liver and pancreas) and the spleen. 2nd branch of the abdominal aorta (1st branches are the paired inferior phrenic arteries). It arises from the anterior aspect of the aorta, at the aortic hiatus of the diaphragm (T12 level). It is usually a short wide trunk,  Stomach Coeliac trunk 1) left gastric, ✓ smallest of the three branches. ✓ It ascends across the diaphragm, ✓ giving rise to oesophageal branches, ✓ continuing anteriorly along the lesser curvature of the stomach. ✓ it anastomoses with the right gastric artery.  Stomach Coeliac trunk 2) Splenic Artery ✓ arises from the coeliac trunk just inferior to the left gastric artery. ✓ It then travels left towards the spleen, running posterior to the stomach and along the superior margin of the pancreas in tortuous course ✓ it is contained within the splenorenal ligament It terminates into five branches which supply the segments of the spleen splenic artery also gives rise to several important vessels: Left gastroepiploic: supplies the greater curvature of the stomach. Anastomoses with the right gastroepiploic artery. Short gastrics: 5-7 small branches supplying the fundus of the stomach. Pancreatic branches: supply the body and tail of the pancreas.  Stomach Coeliac trunk 3) Common Hepatic Artery is the sole arterial supply to the liver As it travels past the superior aspect of the duodenum, it divides into its two terminal branches – proper hepatic - gastroduodenal - Each of these arteries has multiple branches and variation in the arrangement of these branches is common. Proper Hepatic ascends through the lesser omentum towards the liver. It gives rise to: 1) Right gastric: supplies the pylorus and lesser curvature of the stomach. 2) Right and left hepatic: divide inferior to the porta hepatis and supply their respective lobes of the liver. 3) Cystic: branch of the right hepatic artery – supplies the gall bladder. Gastroduodenal descends posterior to the superior portion of the duodenum. Its branches are: 1) Right gastroepiploic: supplies the greater curvature of the stomach. Found between the layers of the greater omentum, which it also supplies. 2) Superior pancreaticoduodenal: divides into an anterior and posterior branch, which supplies the head of the pancreas  Stomach Coeliac trunk Anastomoses Stomach stomach is the only organ to receive arterial supply from all three branches of the coeliac trunk. This is achieved through a system of anastomoses along 1) greater curvature : (gastroepiploic arteries) 2) lesser curvature: (gastric arteries) Pancreas pancreaticoduodenal arcade is a network of arteries that surround and supply the head of the pancreas. There are two main arteries – each has an anterior and posterior branch, that anastomose (e.g. anterior to anterior) forming a ring structure: 1) Superior pancreaticoduodenal– a branch of the gastroduodenal artery. 2) Inferior pancreaticoduodenal – branch of superior mesenteric artery (SMA