The division of the third ventricle in the segments of white rat.

In this paper the third brain ventricle (ventriculus tertius) of rat was studied on the frontal histological slices. Based on the change in the ventricle form and on the peculiarities of the surrounding nerve structures the third ventricle was divided into the upper and lower part and every part was divided into the segments denoted by capital T (tertius) and by the order number; the segments of the lower parts of the third ventricle were indicated as T 1 to T 4 and the segments of the upper part as T 5 to T 9. The adjacent part of aqueductus cerebri (A) was divided into the segments A 1 and A 2. The suggested method of the division aims to serve as an aid for the determination of the precise localization and the denomination of the examined parts of the third ventricle during the morphological studies.