Abstract

The principal objective of this work is to investigate the relationship between lateral functions of the brain and morphology of the hands, eyes and feet. The study was carried out with 233 volunteers within the age range of 18 to 27 years. Out of the total number of participants, 208 (94%) of them were right-handed and the remaining 13 (6%) were left-handed. The participants were divided into two groups and assessed by twenty items. First ten (Q1) and second ten (Q2) items were taken from Edinburg Handedness Inventory (EHI) and the Yetkin Laterality Questionnaire (YLQ). The degree of hand preference was determined by Geshwind scores (GSs). Q1 was used to assess only hand preference, while Q2 was used for laterality of the one side of the body from eye to foot. Statistically, non-significant (p>0.05) difference (3%) was observed between the Q1 (63%) and Q2 (60%). Breadths and lengths of the hands were measured across 2 to 5 metacarpal region, from peripheral line on the wrist to middle fingertip. While the difference between the breadths of right and left hand was significant (p<0.05), the difference between the lengths of hand was non-significant (p> 0.05). The breadths and lengths of the feet were also measured in the same way. Subjects performed three different voluntary motor activities, such as basketing (throwing basketball: BT), aiming at (targeting: TT) and peg moving tasks (PMT) with their right and left hands in turn to perform the tasks, respectively. In the BT and TT tasks, the difference between the right and left hand performance was non-significant (p>0.05), though, the difference was significant (p<0.05) for PMT. The findings suggest that both the proximity of the hand preferences and the difference of the hand sizes could be the results of the hemispheric dominance in the brain. In this study, it was found that there was a significant difference for left- versus right- hand breadths and left and right-hand motor performances which is shown to be both morphological and functional in asymmetry.

Key words: Laterality, hand preference, basketing, targeting, peg-moving, motor performances, brain asymmetry, human.