One-and-a-half syndrome
= caused by lesions of the dorsal pons
Signs:
– ipsilateral conjugate horizontal gaze palsy
– internuclear ophthalmoplegia on contralateral gaze
– exotropia of the eye opposite to the side of the lesion
Causes:
– any lesions causing compression of the dorsal pons – trauma, neoplasms, hydrocephalus
– pontine haemorrhage
– ischaemia – thromboembolic / vasculitis
– multiple sclerosis