Anatomy of Liver - Bare Area

Bare Area of the Liver

• The bare area of the liver is a triangular region on the posterior surface of the right lobe, where there is no intervening peritoneum between the liver and the diaphragm.
• Boundaries of the bare area: anterior - superior layer of coronary ligament, posterior - inferior layer of coronary ligament, laterally - right and left triangular ligaments.

Surfaces of the Liver

• The liver has two surfaces: a convex diaphragmatic surface (anterosuperior) and a relatively flat or even concave visceral surface (postero-inferior).

Diaphragmatic Surface

• The convex upper surface is smooth and molded to the undersurface of the domes of the diaphragm.
• It separates the liver from the pleurae, lungs, pericardium, and heart.
• Covered with visceral peritoneum, except posteriorly in the bare area of the liver.

Visceral Surface

• The posteroinferior surface is related to abdominal viscera.
• Covered with peritoneum, except at the fossa for the gallbladder, porta hepatis, and IVC groove.
• Bears multiple fissures and impressions for contact with other organs.

Fissures of the Liver

• Two sagittally oriented fissures, linked centrally by the transverse porta hepatis, form the letter H on the visceral surface.
• The left fissure is the continuous groove formed by the fissure for the round ligament (lig. teres) and the fissure for the ligamentum venosum.
• The right fissure is the continuous groove formed by the fossa for the gallbladder and the groove for the inferior vena cava.

Relations of Visceral Surface of the Liver

• The visceral surface is related to the stomach and duodenum, esophagus, lesser omentum, gallbladder, right colic flexure, right kidney, and right suprarenal gland.

Porta Hepatis (Hilum of the Liver)

• A transverse fissure found on the posteroinferior surface and lies between the caudate and quadrate lobes.
• Structures passing through the porta hepatis include the right and left hepatic ducts, right and left branches of the hepatic artery, right and left branches of the portal vein, sympathetic and parasympathetic nerve fibers, and a few hepatic lymph nodes.

Ligaments of the Liver

• Falciform ligament: a two-layered fold of peritoneum connecting the liver with the diaphragm and anterior abdominal wall.
• Ligamentum teres (round ligament) of liver: the remains of the umbilical vein, which carried oxygenated blood from the placenta to the fetus.
• Ligamentum venosum: the fibrous remnant of the fetal ductus venosus, which shunted blood from the umbilical vein to the IVC.

Lobes of the Liver

• The liver is divided into a large right lobe and a small left lobe by the attachment of the falciform ligament.
• The right lobe is further divided into a quadrate lobe and a caudate lobe by the presence of the gallbladder, the fissure for the ligamentum teres, the inferior vena cava, and the fissure for the ligamentum venosum.
• The caudate lobe is connected to the right lobe by the caudate process.

Blood Circulation through the Liver

• The blood vessels conveying blood to the liver are the hepatic artery (30%) and portal vein (70%).
• The hepatic artery brings oxygenated blood to the liver.
• The portal vein brings venous blood rich in the products of digestion, which have been absorbed from the gastrointestinal tract to the liver.
• The venous blood is drained by right and left hepatic veins into the inferior vena cava.

Lymph Drainage

• The liver produces a large amount of lymph—about one third to one half of all body lymph.
• The lymph vessels leave the liver and enter several lymph nodes in the porta hepatis.
• The efferent vessels pass to the celiac nodes.

Nerve Supply

• Sympathetic and parasympathetic nerves supply the liver.
• Sympathetic nerves come from the celiac plexus.
• Parasympathetic nerves come from the anterior vagal trunk.

Portal-Systemic (Portacaval) Anastomoses

• Sites: esophagus (lower part), upper anal canal, paraumbilical region, retroperitoneal, and intrahepatic (patent ductus venosus).
• Form venous dilatation called varices in portal hypertension.

Spleen

• The largest single mass of lymphoid tissue.
• Located in the left hypochondrium, deep to 9, 10, and 11 ribs.
• Long axis lies along the shaft of the 10th rib and separated from them by the diaphragm and the costodiaphragmatic recess.
• Ovoid in shape with notched anterior border.
• Lower pole extends forward as far as the midaxillary line.
• Normal size spleen cannot be palpated on clinical examination.

Surfaces of the Spleen

• Diaphragmatic surface: convexly curved to fit the concavity of the diaphragm and curved bodies of the adjacent ribs.
• Visceral surface: related to viscera.
• Borders: superior and anterior borders are sharp, anterior border is notched, and posterior (medial) and inferior borders are rounded.