Liver, Pancreas & Spleen Abdomen, Pelvis & Perineum Unit Lecture 8 د. حيدر جليل الأعسم

Liver It is the largest gland in the body. Functions: production of bile; metabolism; filtration of blood; detoxification of toxins & Heparin synthesis. Liver occupies upper part of abdominal cavity just beneath diaphragm. Greater part of liver is situated under cover of right costal margin, and right hemidiaphragm. It extends to the left to reach left hemidiaphragm. It has convex upper surface molded to undersurface of diaphragm & Posteroinferior (visceral surface) molded to adjacent viscera; Relations: Anteriorly: Diaphragm, right & left costal margins, right & left pleura and lower margins of both lungs, xiphoid process, & anterior abdominal wall in subcostal angle. Posteriorly: Diaphragm, right kidney, hepatic flexure of colon, duodenum, gallbladder, inferior vena cava, and esophagus and fundus of the stomach

Liver Liver is divided into a large right lobe & a small left lobe by attachment of falciform ligament. Right lobe is further divided into a quadrate lobe and a caudate lobe by presence of gallbladder, ligamentum teres fissure, inferior vena cava, and fissure for ligamentum venosum. Porta hepatis (hilum of liver) is found on posteroinferior surface and lies between caudate and quadrate lobes. Liver is completely surrounded by a fibrous capsule but only partially covered by peritoneum. Liver is made up of liver lobules.

Peritoneal Ligaments of Liver Falciform ligament: has sickle-shaped free margin contains ligamentum teres. It passes on to anterior & then superior surfaces of liver and then splits into two layers. Right layer forms upper layer of coronary ligament; left layer forms upper layer of left triangular ligament. Right extremity of coronary ligament is known as right triangular ligament of liver. coronary ligament layers are widely separated, leaving an area of liver devoid of peritoneum (bare area of the liver). Ligamentum teres passes into a fissure on visceral surface of liver and joins left branch of portal vein in porta hepatis. Ligamentum venosum, a fibrous band that is the remains of ductus venosus, is attached to left branch of portal vein and ascends in a fissure on visceral surface of liver to be attached above to inferior vena cava.

Blood Supply of Liver: Arteries: hepatic artery Veins: portal vein divides into right and left terminal branches that enter porta hepatis. Hepatic veins emerge from posterior surface of liver and drain into inferior vena cava. Lymph Drainage: Liver produces a large amount of lymph (1/3 – ½ all body lymph). Porta hepatis lymph nodes send efferent vessels to celiac nodes. Vessels pass from bare area of liver through diaphragm to posterior mediastinal LNs. Nerve Supply: Celiac plexus and anterior vagal trunk which gives large hepatic branch directly to the liver.

Biliary System of liver Bile is secreted by liver, stored and concentrated in gallbladder, and delivered later to the duodenum. Biliary system of liver consists of right & left hepatic ducts, common hepatic duct, bile duct, gallbladder & cystic duct. Right hepatic duct drains right lobe & left duct drains left, caudate & quadrate lobes. Hepatic Ducts Right & left hepatic ducts emerge from right & left lobes of liver in porta hepatis. After a short course, hepatic ducts unite to form common hepatic duct. Common hepatic duct is about 4 cm long & descends within free margin of lesser omentum & joined on its right side by cystic duct to form Common bile duct. Cystic Duct It is about 3.8 cm long & connects neck of GB to common hepatic duct. Mucous membrane of cystic duct is raised to form a spiral fold (spiral valve) that is continuous with a similar fold in neck of gallbladder. Spiral valve serves to keep lumen constantly open.

Biliary System of liver Common Bile Duct: It is about 8 cm long. Its first part lies in right free margin of lesser omentum. Here, it lies in front portal vein and on right of hepatic artery. Its second part is situated behind first part of duodenum to the right of gastroduodenal artery. Its third part lies in a groove on posterior surface of head of pancreas; where itcomes into contact with main pancreatic duct. Common Bile duct ends below by piercing medial wall of 2nd part of duodenum. It is usually joined by main pancreatic duct, & together they open into a small ampulla, called hepatopancreatic ampulla (ampulla of Vater). Ampulla opens into lumen of duodenum by means of a small papilla, major duodenal papilla. Terminal parts of both ducts & ampulla are surrounded by circular muscle, called sphincter of hepatopancreatic ampulla (sphincter of Oddi).

Biliary System of liver Gallbladder: is a pear-shaped sac lying on undersurface of liver. It is divided into: Fundus is rounded & projects below inferior margin of liver, in contact with anterior abdominal wall at level of tip of 9th right costal cartilage. Body lies in contact with visceral surface of liver and is directed upward, backward. Neck becomes continuous with cystic duct. Relations Anteriorly: Anterior abdominal wall & inferior surface of liver Posteriorly: Transverse colon, first & second parts of duodenum Blood Supply: Cystic artery & Cystic vein. Sometimes very small arteries & veins also run between liver and gallbladder. Lymph Drainage: into a cystic lymph node near neck of GB. Then to celiac nodes. Nerve Supply: Celiac plexus also Gallbladder response to hormone cholecystokinin.

Pancreas Pancreas is an elongated structure that lies in epigastrium & left upper quadrant. It is soft and lobulated and situated on posterior abdominal wall along transpyloric plane. Pancreas is divided into: Head: disc shaped, within concavity of duodenum. Part of head extends to left behind superior mesenteric vessels, called uncinate process. Neck: is constricted portion of pancreas & connects head to body. It lies in front of beginning of portal vein & superior mesenteric artery. Body: runs upward and to the left across midline. Tail: passes in splenicorenal ligament & in contact with hilum of spleen. Relations Anteriorly: From right to left: transverse colon and attachment of transverse mesocolon, lesser sac & stomach Posteriorly: From right to left: bile duct, portal and splenic veins, inferior vena cava, aorta, origin of superior mesenteric artery, left psoas muscle, left suprarenal gland, left kidney, and hilum of the spleen.

Pancreas Pancreatic Ducts Main duct of pancreas begins in the tail and runs the length of pancreas. It opens into 2nd part of duodenum with bile duct on major duodenal papilla. Accessory duct of pancreas, when present, drains upper part of head and then opens into duodenum a short distance above main duct on minor duodenal papilla. Accessory duct frequently communicates with main pancreatic duct. Blood Supply Arteries: splenic superior & inferior pancreaticoduodenal arteries. Veins: corresponding veins into portal system. Lymph Drainage: celiac & superior mesenteric lymph nodes. Nerve Supply: Sympathetic & parasympathetic (vagal) nerve.

Spleen It is oval shaped, reddish & largest lymphoid tissue in the body. It has a notched anterior border. It lies just beneath left half of diaphragm close to 9th, 10th & 11th ribs. Its long axis lies along shaft of 10th rib, & its lower pole extends forward only as far as mid-axillary line. Spleen is surrounded by peritoneum, which passes from it at the hilum as gastrosplenic omentum (ligament) to greater curvature of stomach. Peritoneum also passes to the left kidney as splenicorenal ligament. Relations Anteriorly: stomach, tail of pancreas, & left colic flexure. Left kidney lies along its medial border. Posteriorly: diaphragm; left pleura (left costo- diaphragmatic recess); left lung; & 9th, 10th& 11th ribs. Blood Supply Arteries: splenic artery. Veins: splenic vein leaves hilum & runs behind tail and body of pancreas. Behind neck of pancreas. Lymph Drainage: celiac nodes. Nerve Supply: celiac plexus.

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