Bilateral post-pointing is due to defect in -

Ans. is 'c' i.e., Vestibular system Past-pointingo Past-pointing is the deviation of the extremities caused by either cerebellar hemisphere or vestibular disease.o Testing is usually done with arms. The traditional method is to have the patient extend the arm and place his extended finger on the examiner's index finger; then with the eye closed raise the arm directly overhead; than bring it back down precisely onto the examiner's finger,.o If vestibular or cerebellar lesion is there, past pointing (deviation of limb) will be present.o The two types (cerebellar and vestibular) past pointing have different patterns *With vestibular imbalance, the normal labyrinth will push the limb toward the abnormal side and the patient will miss the target. The past pointing will always be to the same side of target and will occur with either limb.With a cerebellar hemispheric lesion, the ipsilateral limbs will have ataxia and incoordination; past pointing occurs only with the involved arm and may be to the side of lesion or erratically to either side of the target.So,o Bilateral past-pointing - Vestibular system defect.o Unilateral past-pointing - Cerebellar hemisphere defect.