It has been postulated that the synkinesis is due to damage to cranial nerve nuclei, caused by peripheral nerve injury and the nuclear lesion releases evolutionarily older neural mechanisms with their tendency toward associated movements, and so primitive reflexes are not inhibited.<unk> <unk>  jaw-winking is an exaggeration of a very weak physiologic co-contraction that has been disinhibited secondary to a congenital brain stem lesion. The stimulation of the trigeminal nerve by contraction of the pterygoid muscles of jaw results in the excitation of the branch of the oculomotor nerve that innervates the levator palpebrae superioris ipsilaterally (on the same side of the face), so the patient will have rhythmic upward jerking of their upper eyelid. There are two major groups of trigemino-oculomotor synkineses: 1) External pterygoid-levator synkinesis is when the eyelid raises upon: * Jaw thrust to opposite side (homolateral external pterygoid) * Jaw is projected forward (bilateral external pterygoid) * Mouth is opened widely 2) Internal pterygoid-levator synkinesis is when the eyelid raises upon teeth clenching External pterygoid-levator synkinesis is the more common group.
Marcus Gunn phenomenon
Tullio phenomenon
Dawn phenomenon
Gallavardin phenomenon
Renbök phenomenon
Ashman phenomenon
Azzopardi phenomenon
Waddell's signs