[Carotid-vertebrobasilar anastomosis]

Anastomoses between carotid and vertebrobasilar vascular bed in extracranial region are less usual compensatory anastomoses of the brain vascular bed. They are either langer compensatory arteries--a. hypoglossica primitiva or a. proatlantica or smaller anastomoses between a. carotis externa and a. vertebralis. A precise differential diagnosis is difficult, as it requires selective catheterization of a. carotis externa, interna, a. vertebralis, or arcography. The paper demonstrates two cases. In a 75 years old man with symptoms of vertebrobasilar insufficiency there was a substantial filling of the whole vertebrobasilar vascular bed in puncture of a. carotis communis. In a 14 years old girl with coarctation of the aorta, acute hemiplegia and occlusion of a. carotis interna in supraclinoideal area there was a conspicuous abnormal filling of large veins in dorsal part of the neck and filling of the atlas loop of a. vertebralis. Selective catheterization could not be performed. The author is of the opinion that the case was an anastomosis between a. occipitalis and a. vertebralis.