[Morphologic asymmetry of the frontal lobe of the cerebral hemisphere in man].

The morphology and the left-right asymmetry of the frontal lobe convexity (sulcus frontalis superior and inferior, sulcus precentralis, gyrus precentralis, gyrus frontalis superior and medius) were studied on 19 formaline fixed human brains. During the study, the gyral and sulcal patterns were marked as similar, partially similar or different. Sulcal patterns on the left and right side were completely different (in at least more than half) in the greatest number of cases. Gyral patterns were also asymmetric (mirror image analysis). However, using the "essential gyral line"--the line indicating longitudinal gyral axis--the results changed dramatically. The majority of patterns appeared to be very similar, indicating that the method of analysis largely influences the results of morphological studies of human brain asymmetry. This explains different findings reported in the literature. We suggest that the use of the "essential gyral line" provides standardized method of morphological analysis, which was not available up to date.