[Morphometry of the brainstem with transverse section of the upper pons]

The authors developed new method of morphometry in the brainstem, which used transverse section of the upper pons. After fixation with formalin, the brainstem was separated from the cerebrum and the cerebellum. Both junctions of midbrain-pons and pons-medulla were cut and then the pons was horizontally separated into four slices. The oral surface of the second slice from oral side, in which the central portion of the locus ceruleus is located, was measured with computed digitizer after enlarging the picture. The authors measured the total size of the slice in the pons (Total S), the tegmentum size (Teg S), the total length (Total L), the tegmentum length (Teg L) and so on. The tegmentum was separated from the base along the ventral line of the medial leminiscus. In the study of 23 control cases (16 to 77 year old, 13 male and 10 female, all were Japanese), Total S (563 +/- 85 mm) and Teg S (136 +/- 19 mm) ranged to some extent, while the percentage of the tegmentum size to the total size (Teg S/Total S X 100: %Teg S) distributed in narrow range (24.4 +/- 2.3%), which was considered to be an appropriate index to reveal normal structure of the upper pons. The percentage of the tegmentum length to the total length (%Teg L) was also an appropriate and a simple index. Using this method to stained preparation, it was confirmed that the tegmentum size of such cases with olivopontocerebellar atrophy or infantile spasms were significantly small.