It should not be confused with alexia without agraphia, an unrelated condition which is also sometimes called "Dejerine syndrome".> Presentation: The condition usually consists of: A weakened tongue on the affected side of the brainstem (due to involvement of the hypoglossal nerve root). Weakness of the limbs on the contralateral (opposite) side (caused by pyramidal tract damage), (medullary pyramid) A loss of discriminative touch, conscious proprioception and vibration sense on the contralateral side (from medial lemniscus involvement).> Sensation of pain and temperature from the body is preserved, as this travels up the spinothalamic tract which is more late al in this part of the brainstem, and supplied by the vertebral or the posterior inferior cerebellar artery. Sensation on the face is usually intact, as this travels mostly by the trigeminal nucleus; most of this nucleus is higher up in the pons, and the spinal part (responsible for pain sensation) is lateral to the infarct. It is in the corticospinal tract. (Patients may have 2 long tract signs caused by a kssion of the MEDIAL LEMNISCUS & the CORTICOSPINAL TRACT, combined with a lesion of the HYPOGLOSSAL NERVE).> Lateral medullary syndrome is caused by the lesion of the posteriori inferior cerebellar artery.> It affects the inferior cerebellar peduncle causing ipsilateral cerebellar signs, dysmetria, ataxia, loss of unconscious proprioception, past pointing etc.> It also causes contralateral loss of pain and temperature sensation, crude touch etc. on trunk, upper and lower limb( spinothalamic tract) there is ipsilateral loss of pain and temperature, on the face, (spinal tract of trigeminal)> Ipsilateral nucleus ambiguous lesions, causes difficulty in swallowing, absent gag reflex, ipsilateral palatal paralysis, the soft palate is pulled towards the normal side, hoarseness of voice etc.> Horner's syndrome on the ipsilateral side.">