Bare area

The bare area of the diaphragmatic surface of the liver is the portion of the liver that is not covered by peritoneum and lies in direct contact with the diaphragm.

General Anatomy of the Bare Area

• Definition: The bare area of the liver is a region on the diaphragmatic (cranial) surface of the liver where the liver is in direct contact with the diaphragm due to the absence of the intervening peritoneum.

• Boundaries: It is generally bounded by folds of peritoneum known as the coronary ligaments, which mark the transition from the peritoneal to the non-peritoneal surface.

• Relations: It is closely associated with the caudal aspect of the diaphragm and indirectly with the pleural cavity and lungs.

Species-Specific Features

Dog and Cat (Carnivores)

• The bare area is well defined and relatively extensive.

• It is located dorsal to the caudate lobe and adjacent to the caudal vena cava which traverses this region.

• In the dog, the bare area is often triangular in shape and directly adjacent to the diaphragm.

Horse

• The bare area is small and less distinct.

• It lies mostly dorsally on the diaphragmatic surface, adjacent to the caudate process and the caudal vena cava.

• Due to the equine liver's more oblique and compact orientation, the area of diaphragmatic contact is limited.

Ruminants (Cattle, Sheep, Goats)

• The bare area is more pronounced in cattle due to the larger size and vertical orientation of the liver.

• It is located dorsally and to the right of the median plane, adjacent to the caudal vena cava and diaphragm.

• In small ruminants, the bare area is less developed but still present in similar dorsal regions.

Pig

• The pig liver has a more symmetrical lobulation.

• The bare area is also present dorsally, bounded by the coronary ligament and adjacent to the caudal vena cava.

• It is relatively larger than in the horse but smaller than in cattle.

Functional Importance

• Peritoneal Reflections: The bare area represents a site where peritoneal continuity is interrupted, which has implications for the spread of infection (e.g., subphrenic abscesses).

• Surgical Relevance: Knowing the location of the bare area is important in surgical access to the liver and understanding the spread of disease.

• Imaging and Pathology: On ultrasonography or CT, the bare area lacks the surrounding peritoneal line, which may help identify the region.