Congenital third nerve palsy with synergistic depression on attempted adduction and trigemino-oculomotor synkinesis: Underpinnings of a spectral dysinnervation disorder.

The authors describe a case of congenital partial pupil-sparing third cranial nerve palsy with absent adduction, synergistic depression of globe and widening of palpebral fissure on attempted adduction and synergistic elevation and adduction on mouth opening and sideways thrusting of jaw. The case illustrates trigemino-oculomotor synkinesis associated with congenital third nerve palsy. The possible mechanism of miswiring involving the medial longitudinal fasciculus and trigeminal nuclei is discussed. At least some cases of congenital third cranial nerve palsy may fall in the realm of congenital cranial dysinnervation disorders (CCDDs) sharing a much wider spectrum of presentation.