Computed tomography of the medulla.

The medulla was studied in cadavers and in 100 patients both with and without the intrathecal administration of contrast material. The computed tomographic (CT) anatomy was correlated with the appearance of anatomic dissections. The pyramids, olives, and inferior cerebellar peduncles produced characteristic contours on cross sections of the medulla. The hypoglossal nerve by its location and course in the medullary cistern could be distinguished from the glossopharyngeal, vagal, and spinal accessory nerves. For optimal evaluation of the medulla, intrathecal administration of metrizamide and 5- and/or 1.5-mm-thick axial and coronal sections are recommended.