Caudate process

The caudate process of the caudate lobe is a portion of the liver located dorsally and caudally in many domestic animals. It is part of the larger caudate lobe, which itself is a distinct division of the liver situated near the porta hepatis. The morphology of the caudate process varies among domestic species but generally retains certain anatomical features.

General Description Across Species

The caudate lobe of the liver typically consists of two subdivisions:

• Papillary process

• Caudate process

The caudate process projects caudally and to the right, often forming a pointed or tongue-like extension. It lies adjacent to the right kidney, fitting into the renal impression on the visceral surface of the liver. This positioning is consistent in species such as cattle, sheep, goats, pigs, horses, and dogs, although species-specific variations exist.

Species-Specific Variations

• Ruminants (Cattle, Sheep, Goats): The caudate process is prominent and triangular, overlying the cranial pole of the right kidney. It is separated from the papillary process by the portal fissure. In these species, the caudate process is an important landmark in liver ultrasonography and necropsy.

• Equines (Horses): The caudate process is rudimentary or absent. The caudate lobe is relatively underdeveloped in horses, and the renal impression is also indistinct or lacking, due to the positioning of the equine kidney and liver.

• Canines (Dogs): The caudate process is well-developed and elongated, making up a large part of the caudate lobe. It fits over the cranial pole of the right kidney and contains branches of the hepatic portal vein and hepatic artery as well as bile ducts.

• Felines (Cats): Similar to dogs, the caudate process is prominent and envelops part of the right kidney.

• Pigs: The caudate process is moderately developed and fits against the right kidney, much like in ruminants. The liver lobulation is more distinct in pigs, which makes the caudate process more anatomically defined.