Traumatic tear of the basilar artery associated with vertebral column injuries.

An unusual case of traumatic basal subarachnoid hemorrhage (SAH) due to a mechanical tear of the basilar artery is reported. A 70-year-old man who had been suffering from cerebrovascular dementia was found dead in a ditch. Externally, subcutaneous hemorrhage with abrasions was observed on the left side of the forehead, face, and lower jaw, together with small contusions in the left superciliary arch. Internally, a 3-mm-long transversal tear of the basilar artery was observed, and dislocations of both C6-C7 and T1-T2 as well as a small fracture of the processus spinosus of C5 were found. No pathological vascular lesions such as aneurysms and vasculitis, other than arteriosclerosis, were observed in the vertebral-basilar system. Ethanol was not detected in the intracardiac blood or in the urine. These findings indicate that when the man fell into the ditch, severe hyperextension occurred as a result of minor blunt forces to the face, and that the traumatic tear of the basilar artery was mechanically caused by overstretching due to hyperextension of the head. It is also suggested that due to his advanced age the muscle tone of the neck might have declined, impairing its defense action, and that head hyperextension might, therefore, occur rather more readily under such conditions.