Background. The importance of normal development of hemispheric dominance and its significance for the
development of an individual is sufficiently known. The internationally not well known procedure according to Zlab
(1) represents one of the most suitable examinations for right-handedness and laterality testing.
Methods and Results. In our study we used one of the most popular questionnaires for phenotype testing of
handedness- Edinburgh’s Inventory (2). According to this questionnaire we have examined 65 children 10 years of
age (± one year), and classified them into 3 groups: a) pure right-handed (n=51), b) pure left-handed (n=5) (all have
fulfilled +90–100% resp. –90–100% of answers on corresponding ten questions) and c) a group of mixed laterality-
-ambidextrous (n=9). The questionnaire we have accomplished by means of objective testing of hair whorl direction
presupposed clockwise in right-handed and counter clockwise in lefthanded. Some of other tests we used turn to be
more reliable than lid opening and using a broom (upper hand) by „dominant“ hand used in Edinburg’s Handedness
Inventory. We have examined also hand, elbow, knee and leg joints excursibiliy (enlarged passivity and/or diminished
muscle tonus) to define cerebellar dominance: right cerebellar hemisphere in right-handed and left cerebellar
hemisphere in left-handed. In the group of pure right-handers we found clockwise hair whorl in 23 of 25 boys. In girls
(probably due tu various hair combing) we found clockwise hair whorl only in 12 of 26 children.
Conclusions. Examination of the hair whorl direction seems to be enrichment for a quick clinical phenotype and
genotype laterality testing.
hair whorl, genotype, right-handedness, left-handedness, hemispheric dominance.