Duodenum- Duodenal Relations-The first part of the duodenum-second part of the duodenum-The third part of the duodenum-The fourth part of the duodenum-Trauma to the Duodenum-Duodenal Ulcer

Duodenum

Description

The duodenum is a C-shaped tube, about25 cm (10 in.) long, which joins the stomach to the jejunum. It receives the openings of the bile and pancreatic ducts. The duodenum curves around the head of the pancreas

 Duodenal Relations

The duodenum is situated in the epigastric and umbilical regions and, for purposes of description, is divided into four parts.

 

The first part of the duodenum

it begins at the pylorus and runs upward and backward on the transpyloric plane at the level of the 1st lumbar vertebra

The relations of this part are as follows:

■■ Anteriorly: The quadrate lobe of the liver and the gallbladder

■■ Posteriorly: The lesser sac (first inch only), the gastroduodenal artery, the bile duct and the portal vein, and the inferior vena cava

■■ Superiorly: The entrance into the lesser sac (the epiploic foramen)

■■ Inferiorly: The head of the pancreas


The second part of the duodenum

runs vertically downward in front of the hilum of the right kidney on the right side of the 2nd and 3rd lumbar vertebrae. About halfway down its medial border, the bile duct and the main pancreatic duct pierce the duodenal wall. They unite to form the ampulla that opens on the summit of the major duodenal papilla. The accessory pancreatic duct, if present, opens into the duodenum a little higher up on the minor duodenal papilla.

The relations of this part are as follows:

■■ Anteriorly: The fundus of the gallbladder and the right lobe of the liver, the transverse colon, and the coils of the small intestine

■■ Posteriorly: The hilum of the right kidney and the right ureter

■■ Laterally: The ascending colon, the right colic flexure, and the right lobe of the liver

■■ Medially: The head of the pancreas, the bile duct, and the main pancreatic duct


The third part of the duodenum

it runs horizontally to the left on the subcostal plane, passing in front of the vertebral column and following the lower margin of the head of the pancreas

The relations of this part are as follows:

■■ Anteriorly: The root of the mesentery of the small intestine, the superior mesenteric vessels contained within it, and coils of jejunum

■■ Posteriorly: The right ureter, the right psoas muscle, the inferior vena cava, and the aorta

■■ Superiorly: The head of the pancreas

■■ Inferiorly: Coils of jejunum Fourth Part of the Duodenum

The fourth part of the duodenum

it runs upward and to the left to the duodenojejunal flexure .The flexure is held in position by a peritoneal fold, the ligament of Treitz, which is attached to the right crus of the diaphragm. The relations of this part are as follows:

■■ Anteriorly: The beginning of the root of the mesentery and coils of jejunum

■■ Posteriorly: The left margin of the aorta and the medial border of the left psoas muscle

Trauma to the Duodenum

Apart from the first inch, the duodenum is rigidly fixed to the posterior abdominal wall by peritoneum and therefore cannot move away from crush injuries. In severe crush injuries to the anterior abdominal wall, the third part of the duodenum may be severely crushed or torn against the third lumbar vertebra.

 

Duodenal Ulcer

As the stomach empties its contents into the duodenum, the acid chyme is squirted against the anterolateral wall of the first part of the duodenum. This is thought to be an important factor in the production of a duodenal ulcer at this site. An ulcer of the anterior wall of the first inch of the duodenum may perforate into the upper part of the greater sac, above the transverse colon. The transverse colon directs the escaping fluid into the right lateral paracolic gutter and thus down to the right iliac fossa. The differential diagnosis between a perforated duodenal ulcer and a perforated appendix may be difficult. An ulcer of the posterior wall of the first part of the duodenum may penetrate the wall and erode the relatively large gastroduodenal artery, causing a severe hemorrhage. The gastroduodenal artery is a branch of the hepatic artery, a branch of the celiac trunk.

Stomach Pain -Gastric Ulcer-Cancer of the Stomach-Gastroscopy-

Stomach Pain

the stretching or spasmodic contraction of the smooth muscle is The main reason for  sensation of pain in the stomach which is caused by its walls and is referred to the epigastrium. It is believed that the paintransmitting 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.

Gastric Ulcer

pepsin  is produced in The mucous membrane of the body of the stomach and, to a lesser extent, that of the fundus produce acid. 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). 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.

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