[Intratympanic course of the internal carotid artery as an accidental finding of ear surgery and as a roentgen diagnostic problem].

The rare anomaly of an intratympanic course of the internal carotid artery is, like the equally rare aneurysm of this artery, a differential diagnosis of tumours of the middle ear. A biopsy would lead to obvious complications. Petrous bone tomography, even using the most modern spiral type of movement, is of limited value because of the difficulty in interpretation and plays little part in the diagnosis as compared with arteriography.