Cervical root compression by a loop of the vertebral artery: case report.

A case of an abnormal loop of the extracranial vertebral artery enlarging the intervertebral foramen at C5-C6 and the transverse foramen at C5 is reported. This occurrence is rare and was associated with cervicobrachial neuralgia caused by neurovascular compression of the C6 root. The patient was cured by microvascular decompression.