Traumatic aneurysm of the extracranial internal carotid artery due to hyperextension of the neck.

Aneurysms of the extracranial internal carotid artery (ICA) are rare. The majority arise iatrogenically after surgery, but a few follow trauma. Traumatic aneurysms of the ICA may follow penetrating injury, direct "blunt trauma" injury or hyperextension of the neck. We report a case of traumatic ICA aneurysm which probably followed a hyperextension injury to the cervical spine in a young woman.