C3 segmental vertebral artery diagnosed by computed tomography angiography.

Extremely rarely, the vertebral artery (VA) enters the subarachnoid space via the intervertebral space of the C2-3 vertebrae. We have identified three cases with this anomalous VA in the literature. We report here another case involving aberrant VA penetration of the dura at the C2-3 vertebral level diagnosed by computed tomography (CT) angiography. A 71-year-old-woman with memory disturbance underwent brain CT and CT angiography. The right VA was aberrant and penetrated the dura at the C1-2 vertebral level. On the left side, the VA penetrated the dura at the C2-3 vertebral level. To our knowledge, this anomalous VA is the first case of C3 segmental VA diagnosed by CT angiography. To prevent VA injury, it is important to identify this variation before performing a posterior fusion of the cervical vertebrae.