Liver Academic Notes

Liver • • • • Position - Hepatorenal recess (Morison’s pouch) – space separating liver from right kidney - Subphrenic recesses (left and right) – spaces separating liver from diaphragm - Subhepatic space – space separating liver from transverse colon - predominantly located in the right hypochondrium and epigastric areas, and extends into the left hypochondrium Anatomy relations - Inferior to diaphragm - Superior to stomach, spleen, bowel - Gallbladder lies on gallbladder fossa of the liver Diaphragmatic surface - covered with visceral peritoneum, except posteriorly in the bare area of the liver where it lies in direct contact with the diaphragm - Glisson’s capsule ✓ bare area is demarcated by the reflection of peritoneum from the diaphragm to it as the anterior and posterior layers of the coronary ligament ✓ These layers meet on the right to form the right triangular ligament and diverge toward the left to enclose the triangular bare area ✓ The anterior layer of the coronary ligament is continuous on the left with the right layer of the falciform ligament, and the posterior layer is continuous with the right layer of the lesser omentum Visceral surface - Covered with visceral peritoneum except the fossa of the gallbladder and the porta hepatis - Two sagittal oriented fissures, linked centrally by the transverse porta hepatis, form the letter H on the visceral surface - The right sagittal fissure is the continuous groove formed anteriorly by the fossa for the gallbladder and posteriorly by the groove for the vena cava. The umbilical (left sagittal) fissure is the continuous groove formed anteriorly by the fissure for the round ligament and posteriorly by the fissure for the ligamentum venosum Anatomical lobes - Left and right lobe – divided by falciform ligament - Caudate lobe – on upper aspect of visceral surface - Quadrate lobe – on lower aspect of visceral surface Fissures and planes - Main lobar fissure (Cantlie’s line): separates right and left lobes surgically ✓ Runs from IVC to gallbladder - Left intersegmental fissure: divides left lobe into medial and lateral segments - Right intersegmental fissure divides right lobe into anterior and posterior segment - Portal plane (horizonal): divides the liver into superior and inferior segments Portal hepatis - Location of entrance and exist of all vessels, nerves and ducts to the liver Peritoneal attachments - Falciform ligament: ✓ Separates right and left lobes anatomically ✓ Attaches liver to anterior abdominal wall - Right and left triangular ligaments ✓ Attach liver to diaphragm - Upper and lower coronary ligaments ✓ Attach liver to diaphragm - Lesser omentum ✓ Attaches liver to duodenum and stomach - Ligamentum venosum ✓ Embryonic remnant of ductus venosus - Ligamentum teres hepatis ✓ Round ligament of the liver ✓ Remnant of umbilical vein Hepatic ducts - Right and left hepatic ducts -> common hepatic duct - Common hepatic duct joins with cystic duct to form bile duct Blood Supply - Receives dual supply - Common hepatic artery > Hepatic artery proper > Right and left hepatic arteries (from heart) - Hepatic portal vein (from stomach/intestines) - Drainage via hepatic vein > IVC Nerve Supply - Parasympathetic from vagus nerve - Sympathetic from hepatic plexus (via celiac plexus) - Glisson’s capsule innervated by lower intercostal nerves - • • • • • • • Gallbladder • Position - lies in the fossa for the gallbladder on the visceral surface of the liver • • - This shallow fossa lies at the junction of the right and left (parts of the) liver Parts - Fundus: the wide blunt end that usually projects from the inferior border of the liver at the tip of the right 9th costal cartilage in the MCL - Body: main portion that contacts the visceral surface of the liver, transverse colon, and superior part of the duodenum - Neck: narrow, tapering end, opposite the fundus and directed toward the porta hepatis; it typically makes an S-shaped bend and joins the cystic duct Cystic duct - 3-4cm long - connects the neck of the gallbladder to the common hepatic duct - The mucosa of the neck spirals into the spiral fold (spiral valve) Fascia The spiral fold helps keep the cystic duct open; thus, bile can easily be diverted into the gallbladder when the distal end of the bile duct is closed by the sphincter of the bile duct and/or hepatopancreatic sphincter, or bile can pass to the duodenum as the gallbladder contracts - The spiral fold also offers additional resistance to sudden dumping of bile when the sphincters are closed, and intra-abdominal pressure is suddenly increasing as during sneeze or cough Blood supply - Right hepatic artery > Cystic artery - Cystic vein > portal vein Innervation - Parasympathetic from vagus - Sympathetic and sensory from celiac plexus - • • Bile duct • • • • Intrahepatic ducts - develop from autonomic growth of the distal biliary ducts that arise from the par’s hepatica of the septum transversum - a network of small tubes that carry bile inside the liver Extrahepatic ducts - Extrahepatic bile ducts are small tubes that carry bile outside of the liver Hepatopancreatic ampulla (ampulla of Vater) - entry point of bile into the second portion of the duodenum Hepatopancreatic sphincter (sphincter of Oddi) - muscular valve in your digestive tract Horizontal Sections