[New views on aberrant innervation of oculomotor muscles ]

Aberrant innervations of oculomotor muscles are a special group of clinical entities, the common sign of which is an abnormal innervation of the oculomotor muscles with nerve fibres which originally were not meant for this purpose. The majority of these anomalies develops during the embryonic period of lesions at the level of nuclei of cranial nerves or peripheral fibres. Congenital aberrations affect most frequently n. VI, less frequently n. III and rarely n. IV. Acquired affections are most frequent in n. III. Abnormal innervation connections concern not only oculomotor muscles but also muscles engaged in mastication and those of the upper eyelid. Clinically they are manifested as eyelid and facial synkinesias. Among aberrant innervations which lack an uniform terminology belong according to the more recent classification the following clinical units: Duan's syndrome, synergic divergence, double-elevator palsy, misdirection syndrome, Marcus Gunn phenomenon, some forms of congenital fibrous syndrome, trigemino-abducens synkinesia, pseudohyperfunction of the lower oblique muscle, crocodile tears syndrome, 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.