The human liver is divided into five distinct lobes.

The five-lobed liver shows how expectations can survive direct access to anatomy.

The idea appears in the Hippocratic tradition and was adopted by Galen. It makes sense in the context of animal dissection: dogs, cats, rabbits, pigs, and some primates have much more conspicuously separated liver lobes than humans.

What is striking is how long the inherited picture survived after human autopsies had resumed. Anatomists did not necessarily walk into a dissection with a blank conceptual slate; ancient authorities told them what structures ought to be there.

Vesalius provides an unusually visible example of self-correction. His 1538 anatomical tables still show a five-lobed liver. During public anatomy at Bologna in 1540, and then in the Fabrica of 1543, he rejected the old description for humans.

Modern anatomy normally describes right, left, caudate, and quadrate lobes, while clinicians often use a separate functional segmental scheme based on blood supply and biliary drainage.

The history is more complicated than a simple “Vesalius corrected Galen” story. Vesalius initially reproduced the inherited error himself and then changed his mind.