Which syndrome is classically associated with medial pons and tegmentum, presenting with hemiparesis and horizontal gaze palsy, and dysarthria?

• A. Millard-Gubler syndrome
• B. Weber's syndrome
• C. Foville's syndrome
• D. Locked-in syndrome

Answer: (C)

Key idea: localization of a brainstem stroke explains the combination of eye movement, limb weakness, and speech symptoms. When the lesion sits in the medial pontine tegmentum, it can disrupt the horizontal gaze center near the abducens nucleus (and the adjacent PPRF) while also involving long motor tracts that run through the tegmentum. This produces a horizontal gaze palsy on the side of the lesion along with contralateral hemiparesis, and bulbar pathways can be affected, leading to dysarthria.

This pattern—dorsal/medial pontine tegmental involvement causing horizontal gaze palsy with contralateral weakness and bulbar (speech) involvement—is classic for Foville's syndrome. Other pontine or brainstem syndromes have different hallmark findings: ventral pontine lesions typically cause facial nerve weakness with ipsilateral involvement and contralateral weakness but not the characteristic horizontal gaze palsy; midbrain lesions produce oculomotor palsy with contralateral motor signs; locked-in syndrome is a ventral pontine catastrophe with quadriparesis and preserved consciousness but classic loss of voluntary movement rather than a focal horizontal gaze palsy with hemiparesis.