Hering's Law, the Levators, and Their Relationship in Disease States

A clinical finding is presented which is of interest in disease states with asymmetric lid positioning. It is suggested that Hering's law applies to the levator palpebrae superioris as well as the extraocular muscles concerned with motion of the globe. Two cases of myasthenia gravis are presented; one case of orbital myositis, and one case of asymmetric lid positioning of undetermined etiology, all of which seem to indicate that the levator palpebrae superioris obeys the same law of equal innervation as previously ascribed only to the extraocular muscles involved in ocular motility.