"Nine" syndrome: A new neuro-ophthalmologic syndrome: Report of two cases.

"Eight-and-a-half" syndrome is a rare condition involving the ipsilateral abducens nucleus or paramedian pontine reticular formation (PPRF), the ipsilateral medial longitudinal fasciculus (MLF), and the adjacent facial colliculus/facial nerve fascicle. The condition is often caused by a lesion (vascular or demyelinating) in the dorsal tegmentum of the caudal pons. There are new variants of this syndrome caused by extension of lesion to involve new adjacent structures in pontine tegmentum. We report two patients with different etiology presenting with clinical features suggestive of eight-and-a-half syndrome associated with hemiataxia representing "nine" syndrome (8½ + ½ = 9) adding new dimension to "eight-and-a-half" syndrome.