calcar avis

A dispute about the calcar avis in the 1860s was satirised as the Great Hippocampus Question.

The anterior part of this fissure gives rise to the prominence of the calcar avis in the posterior cornu of the lateral ventricle.

At a subsequent stage the hippocampus was described as pes hippocampi major, with the calcar avis being named pes hippocampi minor.

The calcar avis and bulb of the posterior cornu are extremely variable in their degree of development; in some cases they are ill-defined, in others prominent.

On its medial wall is a longitudinal eminence, the calcar avis (hippocampus minor), which is an involution of the ventricular wall produced by the calcarine fissure.

At that same time a ridge on the occipital horn was named the calcar avis, but in 1786 this was renamed the hippocampus minor, with the hippocampus being called the hippocampus major.

The ridge was originally described by anatomists as the calcar avis, while the ridge running along the floor of the temporal horn of the lateral ventricle was described by various names, in particular as the hippocampus.