New View on Aberrant Innervation of the Oculomotor Muscles

Overview

Aberrant innervations of oculomotor muscles are a special group of clinicalentities, the common sign of which is an abnormal innervation of the oculomotormuscles with nerve fibres which originally were not meant for this purpose. Themajority of these anomalies develops during the embryonic period of lesions atthe level of nuclei of cranial nerves or peripheral fibres. Congenital aberrationsaffect most frequently n. VI, less frequently n. III and rarely n. IV. Acquiredaffections are most frequent in n. III. Abnormal innervation connections concernnot only oculomotor muscles but also muscles engaged in mastication and thoseof the upper eyelid. Clinically they are manifested as eyelid and facial synkinesias.Among aberrant innervations which lack an uniform terminology belong accordingto the more recent classification the following clinical units: Duan´s syndrome,synergic divergence, double-elevator palsy, misdirection syndrome, MarcusGunn phenomenon, some forms of congenital fibrous syndrome, trigemino-abducenssynkinesia, pseudohyperfunctionof the lower obliquemuscle,crocodile tearssyndrome, and aberrant affection of n. III. The authors describe the course,possible etiology of these anomalies and demonstrate, based on their own observations,clinical cases which can be explained by these mechanisms.

Key words:
congenital and acquired aberrant innervations, aplasia of the nucleiof oculomotor nerves, eyelid synkinesis, facial synkinesis