[The function of the human posterior vertical canal and the extent of central compensation in unilateral dissection of the vestibular nerve].

The vestibular nerve innervates the semicircular canals through two branches. The first branch innervates the anterior vertical and the horizontal canals and the second branch innervates the posterior vertical canal. In transtemporal neurectomy the dissection of the vestibular nerve was sometimes only in the upper part. In these cases the fibres to the posterior vertical canal are still intact. In Düsseldorf 41 patients were treated by transtemporal neurectomy from 1970 until 1977. Five of these patients show an incomplete dissection of the vestibular nerve. They had a normal endolymph circulation with afferent nerve fibres only from the posterior vertical canal. These patients were examined by caloric and rotatory stimulation in different head positions. Vertical and horizontal eye movements were simultaneously recorded. The stimulation of the posterior vertical canal shows a rotatory eye movement. The results were compared with the second Ewald law.