The shape of the inferior horn of the lateral ventricle in relation to collateral and occipitotemporal sulci.

The shape of the inferior horn of the lateral ventricle has been investigated in 100 (50 right and 50 left) human brain hemispheres which were fixed in 40% formaldehyde solution and cut frontally. It has been found that the shape of the inferior horn depends on the course and depth of the collateral and occipitotemporal sulci. In most cases a part from two main ventricular surfaces: the hippocampal and superolateral, there is one surface more, either the inferior-collateral eminence (Type I--97% of cases in the posterior part of the inferior horn, 49%--in the middle and 42%--in the anterior part) or the inferolateral, adjecent to the occipitotemporal sulcus (Type II--0%, 26% and 35%, respectively). In a few cases both collateral eminence and inferolateral surface were present (Type III--3%, 2% and 6% respectively). In type IV neither collateral eminence nor the inferolateral surface appeared (0%, 23%, 17% respectively). The authors suggest to designate the inferolateral surface, not mentioned in the literature, as the occpitotemporal eminence (of the inferior horn).