Condylar canal vein: unfamiliar normal structure as seen at CT and MR imaging.

Abstract

The vein of the posterior condylar canal is often seen (and occasionally misinterpreted) at computed tomography (CT) and magnetic resonance (MR) imaging. The CT appearance of the canal and the vein on a skull specimen was compared with the CT and MR appearance in patients. One condylar canal of the skull specimen was marked with a wire that also indicated the course of the vein beneath the skull base. Axial and coronal CT images of the specimen were compared with CT or MR images of six patients, studied for various clinical indications, in whom the vein was apparent. In all six patients, the location of the vein beneath the skull base corresponded to the location predicted by the wire on the specimen. The normal vein may be prominent or diminutive. Recognition of the normal vein of the posterior condylar canal may prevent misinterpretation of the vein as a neoplasm or an abnormal lymph node at CT or MR imaging.