Anatomy of the Liver Lecture

Overview of the Liver

• The liver is the largest gland and second largest organ in the body, weighing approximately 1500g (2.5% of adult body weight).
• In a mature fetus, the liver is proportionately larger (5% of body weight) and serves as a hematopoietic organ.

Position of the Liver

• The liver is located in the right upper quadrant (mainly) and left upper quadrant of the abdomen.
• It also extends into the right hypochondrium (mainly) and upper part of the epigastric region and left hypochondrium.
• The sharp inferior border of the normal liver crosses the midline at the level of L1 vertebra.
• During inspiration or when standing upright, the liver moves inferiorly and part of it lies in the right lumbar region.
• At full expiration, the liver reaches the level of the 4th intercostal space, and its apex lies deep to the left nipple.

Surfaces of the Liver

• The liver has two surfaces: diaphragmatic and visceral.
• The diaphragmatic surface is smooth, dome-shaped, and convex, representing the anterior, superior, lateral, and some posterior aspects of the liver.
• The visceral surface is irregular and relatively flat or even concave, bearing multiple fissures and impressions from contact with other organs.

Fissures on the Visceral Surface of the Liver

• The visceral surface has two sagittal fissures (right and left) linked centrally by a transverse fissure, forming the letter H on the visceral surface.
• The right sagittal fissure is formed by the fossa for the gallbladder anteriorly and the groove for the vena cava posteriorly.
• The left sagittal (umbilical) fissure is formed by the fissure for the round ligament of the liver anteriorly and the fissure for the ligamentum venosum posteriorly.
• The transverse fissure is formed by the porta hepatis, where the hepatic portal vein, hepatic artery, lymphatic vessels, hepatic nerve plexus, and hepatic bile ducts enter and leave the liver.

Relations of the Liver with Peritoneum

• The liver is an intraperitoneal organ, with its surface covered by visceral peritoneum, except for the bare area of the liver.
• The bare area of the liver is demarcated by the upper and lower layers of the coronary ligament and the right and left triangular ligaments.
• The liver is connected to other structures by peritoneal reflections, including the falciform ligament, coronary ligaments, and lesser omentum.
• The lesser omentum is composed of two ligaments: the hepatogastric ligament and the hepatoduodenal ligament.

Peritoneal Spaces Related to the Liver

• The subphrenic space exists between the diaphragm and the diaphragmatic surface of the liver, separated into right and left subphrenic spaces by the falciform ligament.
• The subhepatic space exists immediately inferior to the liver, with a posterosuperior extension called the hepatorenal recess (hepatorenal pouch or Morison pouch).