Posterior horn of lateral ventricle

Overview
The posterior cornu (occipital horn; postcornu) passes into the occipital lobe, its direction being backward and lateralward, and then medialward.

Its roof is formed by the fibers of the corpus callosum passing to the temporal and occipital lobes.

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.

Above this the forceps posterior of the corpus callosum, sweeping around to enter the occipital lobe, causes another projection, termed the bulb of the posterior cornu.

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.