1. Upper abdominal viscera
abdominal oesophagus & stomach
Applied anatomy of the gastro-esophageal Junction
Vagotomies

2. Gastrointestinal Tract
Esophagus (Abdominal Portion)
The esophagus is a muscular, collapsible tube about 10 in. (25 cm) long that joins the pharynx to the stomach. The esophagus enters the abdomen through an opening in the right crus of the diaphragm. After a course of about 0.5 in. (1.25 cm), it enters the stomach on its right side.
Relations
The esophagus is related
anteriorly to the posterior surface of the left lobe of the liver and posteriorly to the left crus of the diaphragm. The left and right vagi lie on its anterior and posterior surfaces, respectively.

3. •Blood Supply
Arteries
The arteries are branches from the left gastric artery.
Veins
The veins drain into the left gastric vein, a tributary of the portal vein.
•Lymph Drainage
The lymph vessels follow the arteries into the left gastric nodes.
•Nerve Supply
The nerve supply is the anterior and posterior gastric nerves (vagi) and sympathetic branches of the thoracic part of the sympathetic trunk.

4.  Function
The esophagus conducts food from the pharynx into the stomach. Wave like contractions of the muscular coat, called peristalsis.
Gastroesophageal Sphincter
No anatomic sphincter exists at the lower end of the esophagus. However, the circular layer of smooth muscle in this region serves as a physiologic sphincter. As the food descends through the esophagus, relaxation of the muscle at the lower end occurs ahead of the peristaltic wave so that the food enters the stomach. The tonic contraction of this sphincter prevents the stomach contents from regurgitating into the esophagus.
The closure of the sphincter is under vagal control, and this can be augmented by the hormone gastrin and reduced in response to secretin, cholecystokinin, and glucagon.

5. Clinical Notes
The Esophagus
Narrow Areas of the Esophageal Lumen
The esophagus is narrowed at three sites:
●at the beginning, behind the cricoid cartilage of the larynx;
●where the left bronchus and the arch of the aorta cross the front of the esophagus;
●and where the esophagus enters the stomach.
Achalasia of the Cardia (Esophagogastric Junction)
The cause of achalasia is associated with a degeneration of the parasympathetic plexus (Auerbach's plexus) in the wall of the esophagus. Dysphagia (difficulty in swallowing) and regurgitation are common symptoms that are later accompanied by proximal dilatation and distal narrowing of the esophagus.

6. Bleeding Esophageal Varices
At the lower third of the esophagus is an important portal-systemic venous anastomosis. Here, the esophageal tributaries of the left gastric vein (which drains into the portal vein) anastomose with the esophageal tributaries of the azygos veins (systemic veins). Should the portal vein become obstructed, as, for example, in cirrhosis of the liver, portal hypertension develops, resulting in dilatation and varicosity of the portal-systemic anastomoses. Varicosed esophageal veins may rupture, causing severe vomiting of blood (hematemesis).
Anatomy of the Insertion of the Sengstaken-Blakemore Balloon for Esophageal Hemorrhage
The Sengstaken-Blakemore balloon is used for the control of massive esophageal hemorrhage from esophageal varices. The tube is inserted through the nose or by using the oral route. In the average adult the distance between the external orifices of the nose and the stomach is 17.2 in. (44 cm), and the distance between the incisor teeth and the stomach is 16 in. (41 cm).
Anatomy of the Complications
Difficulty in passing the tube through the nose
Damage to the esophagus from overinflation of the esophageal tube
Pressure on neighboring mediastinal structures
Persistent hiccups caused by irritation of the diaphragm by the distended esophagus and irritation of the stomach by the blood.

7. Location and Description
Stomach
Location and Description
The stomach is the dilated portion of the alimentary canal and has three main functions: It stores food, it mixes the food with gastric secretions to form a semifluid chyme, and it controls the rate of delivery of the chyme to the small intestine so that efficient digestion and absorption can take place.
The stomach is situated in the upper part of the abdomen, extending from beneath the left costal margin region into the epigastric and umbilical regions. It is roughly J-shaped and has two openings, the cardiac and pyloric orifices; two curvatures, the greater and lesser curvatures; and two surfaces, an anterior and a posterior surface .
Note the increased thickness of the circular muscle forming the pyloric sphincter.

8. The stomach is relatively fixed at both ends but is very mobile in between. It tends to be high and transversely arranged in the short, obese person (steer-horn stomach) and elongated vertically in the tall, thin person (J-shaped stomach).
The stomach is divided into the following parts:
Fundus: This is dome-shaped and projects upward and to the left of the cardiac orifice. It is usually full of gas.
Body: This extends from the level of the cardiac orifice to the level of the incisura angularis, a constant notch in the lower part of the lesser curvature.
Pyloric antrum: This extends from the incisura angularis to the pylorus.

9. Pylorus: This is the most tubular part of the stomach
Pylorus: This is the most tubular part of the stomach. The thick muscular wall is called the pyloric sphincter, and the cavity of the pylorus is the pyloric canal.
The lesser curvature forms the right border of the stomach and extends from the cardiac orifice to the pylorus. It is suspended from the liver by the lesser omentum.
The greater curvature is much longer than the lesser curvature and extends from the left of the cardiac orifice, over the dome of the fundus, and along the left border of the stomach to the pylorus.

10. The gastrosplenic omentum (ligament) extends from the upper part of the greater curvature to the spleen, and
the greater omentum extends from the lower part of the greater curvature to the transverse colon.
Transverse section of the lesser sac showing the arrangement of the peritoneum in the formation of the lesser omentum, the gastrosplenic omentum, and the splenicorenal ligament. Arrow indicates the position of the opening of the lesser sac.

11. The cardiac orifice is where the esophagus enters the stomach.
The pyloric orifice is formed by the pyloric canal, which is about 1 in. (2.5 cm) long. The circular muscle coat of the stomach is much thicker here and forms the anatomic and physiologic pyloric sphincter. The pylorus lies on the transpyloric plane, and its position can be recognized by a slight constriction on the surface of the stomach.

12. Function of the Pyloric Sphincter
The pyloric sphincter controls the outflow of gastric contents into the duodenum. The sphincter receives
motor fibers from the sympathetic system
and
inhibitory fibers from the vagi.
In addition, the pylorus is controlled by local nervous and hormonal influences from the stomach and duodenal walls.

13. The mucous membrane
of the stomach is thick and vascular and is thrown into numerous folds, or rugae,
that are mainly longitudinal in direction. The folds flatten out when the stomach is distended.
The muscular wall
of the stomach contains longitudinal fibers, circular fibers, and oblique fibers.
The peritoneum (visceral peritoneum)
completely surrounds the stomach. It leaves the lesser curvature as the lesser omentum and the greater curvature as the gastrosplenic omentum and
the greater omentum.

14. Relations
Anteriorly:
The anterior abdominal wall, the left costal margin, the left pleura and lung, the diaphragm, and the left lobe of the liver.

15. Posteriorly:
The lesser sac, the diaphragm, the spleen, the left suprarenal gland, the upper part of the left kidney, the splenic artery, the pancreas, the transverse mesocolon, and the transverse colon.
Structures situated on the posterior abdominal wall behind the stomach.

16. The arteries are derived from the branches of the celiac artery.
Blood Supply
Arteries
The arteries are derived from the branches of the celiac artery.
The left gastric artery arises from the celiac artery. It passes upward and to the left to reach the esophagus and then descends along the lesser curvature of the stomach. It supplies the lower third of the esophagus and the upper right part of the stomach.
Arteries that supply the stomach. Note that all the arteries are derived from branches of the celiac artery.

17. The right gastric artery arises from the hepatic artery at the upper border of the pylorus and runs to the left along the lesser curvature. It supplies the lower right part of the stomach.
The short gastric arteries arise from the splenic artery at the hilum of the spleen and pass forward in the gastrosplenic omentum (ligament) to supply the fundus.
The left gastroepiploic artery arises from the splenic artery at the hilum of the spleen and passes forward in the gastrosplenic omentum (ligament) to supply the stomach along the upper part of the greater curvature.
The right gastroepiploic artery arises from the gastroduodenal branch of the hepatic artery. It passes to the left and supplies the stomach along the lower part of the greater curvature.

18. Veins
The veins drain into the portal circulation. The left and right gastric veins drain directly into the portal vein. The short gastric veins and the left gastroepiploic veins join the splenic vein. The right gastroepiploic vein joins the superior mesenteric vein.
Tributaries of the portal vein.

19. Lymph Drainage
The lymph vessels follow the arteries into the left and right gastric nodes, the left and right gastroepiploic nodes, and the short gastric nodes. All lymph from the stomach eventually passes to the celiac nodes located around the root of the celiac artery on the posterior abdominal wall.
Lymph drainage of the stomach. Note that all the lymph eventually passes through the celiac lymph nodes.

20. Nerve Supply
The nerve supply includes sympathetic fibers derived from the celiac plexus and parasympathetic fibers from the right and left vagus nerves.
The anterior vagal trunk, which is formed in the thorax mainly from the left vagus nerve, enters the abdomen on the anterior surface of the esophagus. The trunk, which may be single or multiple, then divides into branches that supply the anterior surface of the stomach. A large hepatic branch passes up to the liver, and from this a pyloric branch passes down to the pylorus.
Distribution of the anterior and posterior vagal trunks within the abdomen. Note that the celiac branch of the posterior vagal trunk is distributed with the sympathetic nerves as far down the intestinal tract as the left colic flexure.

21. The posterior vagal trunk, which is formed in the thorax mainly from the right vagus nerve, enters the abdomen on the posterior surface of the esophagus. The trunk then divides into branches that supply mainly the posterior surface of the stomach. A large branch passes to the celiac and superior mesenteric plexuses and is distributed to the intestine as far as the splenic flexure and to the pancreas.
The sympathetic innervation of the stomach carries a proportion of pain-transmitting nerve fibers, whereas the parasympathetic vagal fibers are secretomotor to the gastric glands and motor to the muscular wall of the stomach. The pyloric sphincter receives motor fibers from the sympathetic system and inhibitory fibers from the vagi.

22. Clinical Notes Trauma to the Stomach
It is protected on the left by the lower part of the rib cage. These factors greatly protect the stomach from blunt trauma to the abdomen. However, its large size makes it vulnerable to gunshot wounds.
Gastric Ulcer
The mucous membrane of the body of the stomach and, to a lesser extent, that of the fundus produce acid and pepsin. The secretion of the antrum and pyloric canal is mucous and weakly alkaline. The secretion of acid and pepsin is controlled by two mechanisms: nervous and hormonal. The vagus nerves are responsible for the nervous control, and the hormone gastrin, produced by the antral mucosa, is responsible for the hormonal control. In the surgical treatment of chronic gastric and duodenal ulcers, attempts are made to reduce the amount of acid secretion by sectioning the vagus nerves (vagotomy) and by removing the gastrin-bearing area of mucosa, the antrum (partial gastrectomy).
Areas of the stomach that produce acid and pepsin (blue) and alkali and gastrin (red).

23. Gastric ulcers occur in the alkaline-producing mucosa of the stomach, usually on or close to the lesser curvature. A chronic ulcer invades the muscular coats and, in time, involves the peritoneum so that the stomach adheres to neighboring structures. An ulcer situated on the posterior wall of the stomach may perforate into the lesser sac or become adherent to the pancreas. Erosion of the pancreas produces pain referred to the back. The splenic artery runs along the upper border of the pancreas, and erosion of this artery may produce fatal hemorrhage. A penetrating ulcer of the anterior stomach wall may result in the escape of stomach contents into the greater sac, producing diffuse peritonitis. The anterior stomach wall may, however, adhere to the liver, and the chronic ulcer may penetrate the liver substance.
Gastric Pain
The sensation of pain in the stomach is caused by the stretching or spasmodic contraction of the smooth muscle in its walls and is referred to the epigastrium. It is believed that the pain-transmitting fibers leave the stomach in company with the sympathetic nerves. They pass through the celiac ganglia and reach the spinal cord via the greater splanchnic nerves.

24. Cancer of the Stomach
Because the lymphatic vessels of the mucous membrane and submucosa of the stomach are in continuity, it is possible for cancer cells to travel to different parts of the stomach, some distance away from the primary site. Cancer cells also often pass through or bypass the local lymph nodes and are held up in the regional nodes. For these reasons, malignant disease of the stomach is treated by total gastrectomy, which includes the removal of the lower end of the esophagus and the first part of the duodenum; the spleen and the gastrosplenic and splenicorenal ligaments and their associated lymph nodes; the splenic vessels; the tail and body of the pancreas and their associated nodes; the nodes along the lesser curvature of the stomach; and the nodes along the greater curvature, along with the greater omentum. This radical operation is a desperate attempt to remove the stomach en bloc and, with it, its lymphatic field. The continuity of the gut is restored by anastomosing the esophagus with the jejunum.
Gastroscopy
Gastroscopy is the viewing of the mucous membrane of the stomach through an illuminated tube fitted with a lens system. The patient is anesthetized and the gastroscope is passed into the stomach, which is then inflated with air. With a flexible fiberoptic instrument, direct visualization of different parts of the gastric mucous membrane is possible. It is also possible to perform a mucosal biopsy through a gastroscope.

25. Nasogastric Intubation
Nasogastric intubation is a common procedure and is performed to empty the stomach, to decompress the stomach in cases of intestinal obstruction, or before operations on the gastrointestinal tract; it may also be performed to obtain a sample of gastric juice for biochemical analysis.
Three sites of esophageal narrowing may offer resistance to the nasogastric tube at the beginning of the esophagus behind the cricoid cartilage (7.2 in. [18 cm]), where the left bronchus and the arch of the aorta cross the front of the esophagus (11.2 in. [28 cm]), and where the esophagus enters the stomach (17.2 in. [44 cm]). The upper esophageal narrowing may be overcome by gently grasping the wings of the thyroid cartilage and pulling the larynx forward. This maneuver opens the normally collapsed esophagus and permits the tube to pass down without further delay.
Anatomy of Complications
The nasogastric tube enters the larynx instead of the esophagus.
Rough insertion of the tube into the nose will cause nasal bleeding from the mucous membrane.
Penetration of the wall of the esophagus or stomach. Always aspirate tube for gastric contents to confirm successful entrance into the stomach.

26. Vagotomy
Vagotomies may be truncal, highly selective, or extended highly selective.
Highly selective vagotomy (HSV):
HSV provides the best overall operative treatment, and can be safely performed in most patient.
While the role of open operations for ulcer complications is well established, there is little doubt that laparoscopic approaches will increase in popularity for appropriate candidates. If we continue to consider the merits of this operation compared with alternatives, HSV will always have a well-deserved place among surgical options.

27. Gastric Ulcers, Helicobacter pylori, and Vagotomy
Gastric ulcers are open lesions of the mucosa of the stomach, whereas the term peptic ulcers is applied to lesions of the mucosa of the pyloric canal or, more often, the duodenum. Most ulcers (9 of 10) of the stomach and duodenum are associated with an infection of a specific bacterium, Helicobacter pylori (H. pylori).

28. Because the secretion of acid by parietal cells of the stomach is largely controlled by the vagus nerves, vagotomy (surgical section of the vagus nerves) is performed in some people with chronic or recurring ulcers to reduce the production of acid. Vagotomy may also be performed in conjunction with resection of the ulcerated area (antrectomy, or resection of the pyloric antrum) to reduce acid secretion. A truncal vagotomy (surgical section of the vagal trunks) is rarely performed because the innervation of other abdominal structures is also sacrificed. In selective gastric vagotomy, the stomach is denervated but the vagal branches to the pylorus, liver and biliary ducts, intestines, and celiac plexus are preserved. A selective proximal vagotomy attempts to denervate even more specifically the area in which the parietal cells are located, hoping to affect the acid-producing cells while sparing other gastric function (motility) stimulated by the vagus nerve.
Vagotomy. Truncal (A), selective gastric (B), and selective proximal (C) vagotomy are shown.

29. A posterior gastric ulcer may erode through the stomach wall into the pancreas, resulting in referred pain to the back. In such cases, erosion of the splenic artery results in severe hemorrhage into the peritoneal cavity. Pain impulses from the stomach are carried by visceral afferent fibers that accompany sympathetic nerves. This fact is evident because the pain of a recurrent peptic ulcer may persist after complete vagotomy, whereas patients who have had a bilateral sympathectomy may have a perforated peptic ulcer and experience no pain.