Unilateral paralysis of the elevators of supranuclear origin.

UNILATERAL paralysis of the elevators (inferior oblique and superior rectus) is a syndrome treated only briefly by most authors (see Duke-Elder, 1949). It is, nevertheless, a relatively frequent clinical entity and of great importance in practice. Bielschowsky (1939) considered this paralysis and the anterior internuclear syndrome to be the only unilateral supranuclear paralysis which could be diagnosed clinically. White (1942) described the syndrome and suggested a useful semiological classification. Malbran (1944, 1949) and Malbran and Sevrin (1952) have accepted Bielschowsky's idea of pathological evolution, and White's classification of the signs. Apart from clinical reasons, and considering the anatomy only, it is clearly difficult to assign this syndrome to a nuclear or infranuclear lesion. For the first, it would be necessary to accept the existence of a lesion which slowly affected the nuclei corresponding to the superior rectus and inferior oblique, without affecting the intra-ocular muscles and other muscles innervated by the 3rd nerve. An infranuclear lesion is even less probable, as it entails the postulation of a pedicular or truncular lesion which would affect selectively these fibres destined to the two muscles in question. That both elevator muscles of the same eye could be affected by a paralysis of orbital origin is also improbable in view of their anatomical separation. Per contra clinical arguments favour a supranuclear pathology, as in these cases the integrity of the peripheral neurone can be demonstrated. In examining a patient with this syndrome, it is possible to ascertain that the movements of elevation of one eye are totally absent; occasionally both muscles appear completely inactive, in other cases the functional deficiency of the inferior oblique is more marked than that of the superior rectus or vice versa. Generally, the patient offers the whole clinical picture of vertical strabismus with descent of the affected eye with pseudo or true ptosis (both forms exist as we will see later). More rarely the paralysed eye maintains fixation, and the normal eye displays a strong vertical strabismus with elevation in secondary deviation. If the patient is asked to look up, the eye will not usually succeed in rising above the horizontal meridian. There exist, nevertheless, special manoeuvres which enable us to show the integrity of the elevator action of these muscles.