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Significance of Handedness in neurology

  • Handedness is the preference to use the hand of a particular side right or left for complicated, fine and skillful motor acts
  • Dominant hand is the hand  that is used for combing the hair , buttoning the shirt or picking up a coin. This is also be tested indirectly by asking the person to kick a ball or to use his or her eye to see through a small hole. 
  • The leg or the eye used by the person preferentially, gives a clue to the side of cerebral dominance.
  • When the person is  asked to fold his arms across the chest, the dominant arm is placed anteriorly. likewise, when asked  the patient to stand at ease, the dominant hand comes posteriorly.
  • There is an anatomic difference in the sizes of dominant and nondominant cerebral hemispheres.
  • Planum temporale is an area adjacent to the auditory centre of Heschl's transverse gyrus,it is larger in the left hemisphere in the right handed individuals. Left handedness either hereditary or may due to disease of the left hemisphere in early life.
  • Left hemisphere dominance for language occurs in 95% of right handed people. Even in 50% of left handed individuals, left hemisphere is dominant.