Liver

The liver is the largest abdominal gland, located in the abdominal cavity, mainly in the right hypochondrium and right flank, and partially protected by the rib cage. It plays a central role in metabolism, plasma protein synthesis, detoxification, glycogen storage, and bile production.

The canine liver is divided into six main lobes:

• Right lateral lobe

• Right medial lobe

• Quadrate lobe: located medially, opposite the gallbladder.

• Caudate lobe: includes the caudate process and the papillary process.

• Left lateral lobe

• Left medial lobe

These lobes are separated by ligaments:

• Falciform ligament: connects the liver to the ventral abdominal wall and the diaphragm.

• Coronary ligament: surrounds the diaphragm-facing fossa.

• Triangular ligaments: lateral extensions of the coronary ligaments.

The liver has different surfaces:

• Diaphragmatic surface: convex, in contact with the diaphragm.

• Visceral surface: concave, in relation to the stomach, intestines, right kidney, and gallbladder.

The porta hepatis is the entry point on the visceral surface for the portal vein, hepatic artery, and nerves, and the exit point for the bile ducts.

The gallbladder is located on the visceral surface, between the quadrate and right lobes. The liver’s blood supply relies on a dual inflow: the hepatic artery delivers oxygenated blood, while the portal vein carries blood from the digestive tract. Ligaments provide anchoring and stabilization of the liver within the abdominal cavity.

Comparative anatomy:

• In the cat, ruminants, and pig, the liver organization is similar to that of the dog.

• In the horse, the liver is divided into five lobes (right, left medial, left lateral, caudate, quadrate), and the gallbladder is absent.

• In humans, the right and left lobes are large and symmetrical, while the quadrate and caudate lobes are smaller. The gallbladder is located beneath the right lobe.