Traumatic dissection of the extracranial internal carotid artery.

Six cases of traumatic dissection of the extracranial carotid artery that were all treated conservatively are reported. The initial trauma was believed to be an intimal tear caused by severe stretching of the artery over the process of a cervical vertebra due to sudden hyperextension and lateral flexion of the neck to the opposite side. No clinical evidence of neck trauma was present, but one patient had roentgenographic evidence of cervical spine fracture. Four-vessel angiography was diagnostic in all six patients and was useful during follow-up in the four in whom it was done.