Bilateral Variation in Adolescents: Handedness, Arm Positioning and Thumb Positioning

摘要

The interrelation between hand and brain apprehend the creativity of researchers because it would be so helpful and so non-invasive to study patterns of brain asymmetries by using a person's handedness as a marker for the lateralization of brain. In total population 10% of people are left handed and this is due to the asymmetry of the cerebral hemisphere.The motor and sensory activities of the human body are strongly associated with the structural and functional behavior of the two cerebral hemispheres in controlling the postural lateral preferences like arm positioning,thumb positioning and hand preferences. The establishment of motor system in humans pursue the basic principle of control of distal movements contralaterally. This principle is reflected at the anatomical level in virtually complete crossing of corticospinal fibers which innervate distal muscles, including hand muscles. However, a particular feature of the human brain is that the two cerebral hemispheres are not symmetrical but including the motor control of the both hands they are specialized in a number of functions. Arm positioning is the preference of the arm during folding and thumb positioning is the preference of the thumb during interlocking the digits. According to handedness anatomical asymmetry of language regions also appears to vary . In the present study we attempted to find the association between handedness, arm positioning,thumb positioning and foot positioning in an adolescent population.