Abdominal Cavity PDF

M.B.Ch.B. M.Sc. Ph.D. Anatomy 1/10/2024 1  Learning Objectives 1. Label the Peritoneum and Peritoneal Cavity. 2. Describe the Anatomy of Abdominal Viscera. 3. Demonstrate the Anatomical parts of GIT: I. Stomach II. Duodenum...

M.B.Ch.B. M.Sc. Ph.D. Anatomy 1/10/2024 1  Learning Objectives 1. Label the Peritoneum and Peritoneal Cavity. 2. Describe the Anatomy of Abdominal Viscera. 3. Demonstrate the Anatomical parts of GIT: I. Stomach II. Duodenum III. Jejunum IV. Ileum 1/10/2024 Email :[email protected] Website :http://Alkafeel.edu.iq 2  Peritoneum and Peritoneal Cavity Peritoneum is a thin membrane lines the wall of the abdominal cavity and covers much of the viscera. The parietal peritoneum lines the walls of the cavity and the visceral peritoneum covers the viscera. Between the parietal and visceral layers of peritoneum is a potential space (the peritoneal cavity). Email :[email protected] Website :http://Alkafeel.edu.iq 3  Peritoneal Reflections Abdominal viscera are either suspended in the peritoneal cavity by folds of peritoneum (mesenteries) and they are called intrapritoneal organs, like stomach, jejunum, ileum, transverse and sigmoid colon. Organs outside the peritoneal cavity, with only one surface or part of one surface covered by peritoneum, are retroperitoneal. They are either partially retroperitoneal like ascending and descending colon, or totally retroperitoneal like duodenum. Email :[email protected] Website :http://Alkafeel.edu.iq 4  Peritoneal Cavity It is subdivided further into the greater sac and the lesser sac (omental bursa). Greater sac is most of the space in the peritoneal cavity from the diaphragm and continue downward to the pelvic cavity. Lesser sac (Omental bursa) is smaller subdivision posterior to the stomach and liver and is continuous with greater sac through an opening (omental foramen). Email :[email protected] Website :http://Alkafeel.edu.iq 5  Omental Foramen (Epiploic foramen) is surrounded by numerous structures covered with peritoneum, include: a) Anteriorly: portal vein, hepatic artery and bile duct. b) Posteriorly: inferior vena cava c) Superiorly: caudate lobe of liver d) Inferiorly: first part of duodenum Email :[email protected] Website :http://Alkafeel.edu.iq 6  Peritoneal Folds There are three types of folds (omentum, mesentery and ligament) developed from original dorsal and ventral mesenteries suspending the developing GIT in the embryonic coelomic cavity. Some contain vessels and nerves supplying the viscera, while others help maintain the proper positioning of the viscera. Email :[email protected] Website :http://Alkafeel.edu.iq 7  Omentum The omenta consist of two layers of peritoneum, which pass from the stomach and the first part of the duodenum to other viscera. There are two omenta: 1. The greater omentum is a large, apron-like, peritoneal fold that attaches to the greater curvature of the stomach and the first part of the duodenum and drapes inferiorly over jejunum and ileum then return upward to attach to transverse colon. Email :[email protected] Website :http://Alkafeel.edu.iq 8  Omentum 2. The lesser omentum is also doubled layers of peritoneum extends from lesser curvature of stomach and first part of duodenum to inferior surface of liver. Email :[email protected] Website :http://Alkafeel.edu.iq 9  Mesenteries They are peritoneal folds that attach viscera to the posterior abdominal wall. They allow some movement and provide a canal for vessels, nerves, and lymphatics to reach the viscera and include: a. The mesentery-associated with parts of the small intestine. b. The transverse mesocolon-associated with the transverse colon. c. The sigmoid mesocolon-associated with the sigmoid colon. Email :[email protected] Website :http://Alkafeel.edu.iq 10  Peritoneal Ligaments Peritoneal ligaments are two-layered folds of peritoneum that connect solid viscera to the abdominal walls. The liver, for example, is connected to the diaphragm by the falciform ligament, the coronary ligament, and the right and left triangular ligaments. Email :[email protected] Website :http://Alkafeel.edu.iq 11  Abdominal Viscera GIT: stomach, small and large intestines, liver, pancreas, and gallbladder. Spleen. Urinary system: kidneys and ureters. Suprarenal glands. Major neurovascular structures. Email :[email protected] Website :http://Alkafeel.edu.iq 12  Stomach It is the most dilated part of the gastrointestinal tract and has a J-like shape. Positioned between the abdominal esophagus and the small intestine, the stomach is in the epigastric, umbilical, and left hypochondrial regions of the abdomen. Email :[email protected] Website :http://Alkafeel.edu.iq 13  Stomach The stomach is divided into four regions: 1) Cardia 2) Fundus 3) Body 4) Pylorus; antrum and canal Stomach has two curvatures: greater and lesser. The anterior surface lies behind diaphragm, liver and anterior abdominal wall. Posterior surface lies on left kidney, spleen & pancreas. Email :[email protected] Website :http://Alkafeel.edu.iq 14  Stomach Other features of the stomach include: A. Greater curvature, which is a point of attachment for the gastrosplenic ligament and the greater omentum B. Lesser curvature, which is a point of attachment for the lesser omentum C. Cardial notch, which is the superior angle created when the esophagus enters the stomach D. Angular incisure, which is a bend on the lesser curvature. Email :[email protected] Website :http://Alkafeel.edu.iq 15  Wall of Stomach 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 visceral peritoneum completely surrounds the stomach. It leaves the lesser curvature as the lesser omentum and the greater curvature as the greater omentum. Email :[email protected] Website :http://Alkafeel.edu.iq 16  Blood Supply of Stomach The arteries are derived from the branches of the celiac artery: 1) Left gastric artery from celiac artery. 2) Right gastric artery from hepatic artery. 3) Short gastric arteries from splenic artery. 4) Left gastroepiploic artery from splenic artery. 5) Right gastroepiploic artery from gastroduodenal artery. Email :[email protected] Website :http://Alkafeel.edu.iq 17 Blood Supply of Stomach Email :[email protected] Website :http://Alkafeel.edu.iq 18  Veins of Stomach 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. Email :[email protected] Website :http://Alkafeel.edu.iq 19  Nerve supply of Stomach 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. The posterior vagal trunk, which is formed in the thorax mainly from the right vagus nerve. Email :[email protected] Website :http://Alkafeel.edu.iq 20  Lymphatics of Stomach 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. Email :[email protected] Website :http://Alkafeel.edu.iq 21  Gastric Ulcer Stomach ulcers (gastric ulcers) are open sores that develop on the lining of the stomach. The most common symptom of a stomach ulcer is a burning pain in the center of the abdomen, in addition to indigestion, nausea and heart burn. Stomach ulcers occur when the layer protecting the stomach lining from stomach acid breaks down. This allows the stomach lining to become damaged. Email :[email protected] Website :http://Alkafeel.edu.iq 22  Small Intestine It is convoluted tube extending from pylorus till ileocecal junction. It is about 6 m (20 ft) long It consists of three parts: 1) Duodenum: 25 cm 2) Jejunum: 2/5 of small intestine 3) Ileum: 3/5 of small intestine Email :[email protected] Website :http://Alkafeel.edu.iq 23  DUODENUM First part of small intestine, C shape, enclosing of head of pancreas. It is fixed to posterior abdominal wall. Bile duct and pancreatic duct open at midway of the second part. Its lumen is the widest of the small intestine. Email :[email protected] Website :http://Alkafeel.edu.iq 24  The duodenum is situated in the epigastric and umbilical regions and, for purposes of description, is divided into four parts. 1. The first part of the duodenum begins at the pylorus and runs upward and backward on the transpyloric plane at the level of the first lumbar vertebra. It passes anteriorly to the bile duct, gastroduodenal artery, portal vein, and inferior vena cava. Clinically, the beginning of this part of the duodenum is referred to as the ampulla or duodenal cap, and most duodenal ulcers occur in this part of the duodenum. 2. The second (Descending) part of the duodenum runs vertically downward in front of the hilum of the right kidney on the right side of the second and third lumbar vertebrae, contains the major duodenal papilla, which is the common entrance for the bile and pancreatic ducts, and the minor duodenal papilla, which is the entrance for the accessory pancreatic duct. Email :[email protected] Website :http://Alkafeel.edu.iq 25 3. The third (inferior or transverse) part of the duodenum 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. crossing the inferior vena cava, the aorta, and the vertebral column. It is crossed anteriorly by the superior mesenteric artery and vein. 4. The fourth (ascending) part of the duodenum passes upward on, or to the left of, the aorta to approximately the upper border of vertebra L2 and terminates at 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. Email :[email protected] Website :http://Alkafeel.edu.iq 26 Email :[email protected] Website :http://Alkafeel.edu.iq 27  Blood supply of Duodenum The superior pancreaticoduodenal artery, a branch of the gastroduodenal artery supplies the upper half. The inferior pancreaticoduodenal artery, a branch of the superior mesenteric artery supplies the lower half. The superior pancreaticoduodenal vein drains into the portal vein; the inferior vein joins the superior mesenteric vein. Email :[email protected] Website :http://Alkafeel.edu.iq 28  Lymph Drainage of Duodenum The lymph vessels follow the arteries and drain upward via pancreaticoduodenal nodes to the gastroduodenal nodes and then to the celiac nodes. Drain downward via pancreaticoduodenal nodes to the superior mesenteric nodes around the origin of the superior mesenteric artery. Email :[email protected] Website :http://Alkafeel.edu.iq 29  The jejunum and ileum measure about 20 ft (6 m) long; the upper two fifths of this length make up the jejunum. Each has distinctive features, but there is a gradual change from one to the other. The jejunum begins at the duodenojejunal flexure, and the ileum ends at the ileocecal junction. The coils of jejunum and ileum are freely mobile and are attached to the posterior abdominal wall by a fan-shaped fold of peritoneum known as the mesentery of the small intestine. Email :[email protected] Website :http://Alkafeel.edu.iq 30  Jejunum can be distinguished from the ileum by the following features: 1. The jejunum lies coiled in the upper part of the peritoneal cavity below the left side of the transverse mesocolon; the ileum is in the lower part of the cavity and in the pelvis. 2. The jejunum is wider bored, thicker walled, and redder than the ileum. Email :[email protected] Website :http://Alkafeel.edu.iq 31 3. The jejunal mesenteric vessels form only one or two arcades, with long and infrequent branches passing to the intestinal wall. The ileum receives numerous short terminal vessels that arise from a series of three or four or even more arcades 4. Aggregations of lymphoid tissue (Peyer's patches) are present in the mucous membrane of the lower ileum along the antimesenteric border. In the living persons these may be visible through the wall of the ileum from the outside. Email :[email protected] Website :http://Alkafeel.edu.iq 32  The arterial supply is from branches of the superior mesenteric artery. The intestinal branches arise from the left side of the artery and run in the mesentery to reach the gut. They anastomose with one another to form a series of arcades. The lowest part of the ileum is also supplied by the ileocolic artery. Email :[email protected] Website :http://Alkafeel.edu.iq 33  The veins correspond to the branches of the superior mesenteric artery and drain into the superior mesenteric vein. The lymph vessels pass through many intermediate mesenteric nodes and finally reach the superior mesenteric nodes, which are situated around the origin of the superior mesenteric artery. Email :[email protected] Website :http://Alkafeel.edu.iq 34 1. Gray’s Anatomy for Students. 2. Clinical Anatomy by Regions. Richard S. Snell. 3. Clinically Oriented Anatomy. Keith L. Moore. Email :[email protected] Website :http://Alkafeel.edu.iq