Restricted dissociated sensory loss in a patient with a lateral medullary syndrome: A clinical-MRI study

Various sensory syndromes in lateral medullary infarctions are described. A small variation in the location of a lesion may lead to very different clinical features, owing to the complex anatomy of the medulla oblongata. MRI may identify the location and extent of the ischemic lesions, allowing a clear clinical-anatomical correlation.

We describe a man with an ischemic lesion in the right portion of the lower medulla that presented a contralateral impairment of spinothalamic sensory modalities and an ipsilateral impairment of lemniscal modalities with a restricted distribution (left forearm and hand, right hand and fingers, respectively). The restricted and dissociated sensory abnormalities represent the only permanent neurological consequence of that lesion.

The atypical sensory syndrome may be explained by the involvement of the medial portion of spinothalamic tract and the lateral portion of archiform fibers at the level of the lemniscal decussation.