Radiographic position of the trigeminal nerve in the skull for angiographic determination of arterial-nerve relationship in trigeminal neuralgia: results of a radiologic-anatomic study.

The positions of 20 trigeminal nerves in the skulls of 12 cadavers were evaluated radiographically. Small metal clips were attached to the nerves and radiographs were obtained in straight AP, Towne and lateral projections. It was found that the trigeminal nerve had a fairly constant position in the skull with respect to the internal auditory meatus in the AP and Towne projections and the petrous ridges in the lateral view. This information can be used during vertebral angiography to predict whether an arterial loop is sufficiently close to the trigeminal nerve root for arterial compression of the nerve, causing trigeminal neuralgia, to be a realistic possibility.