RESUMO
The authors proposed a new rentgenometrie method allowing objective determination of the site of expanding lesions in the posterior cranial fossa. On the lateral angiograms of the vertebral arteries they determined the position of the choroid point of the posterior inferior cerebellar artery in relation to the line joining internal occipital protuberance with the upper ridge of acetabulum of the mandibular articulation. On the material of 50 subjects with expanding lesions of the posterior cranial fossa the authors determined interrelationship between the shift of the choroid point and the site of the lesion. They pointed out that the presented method can be of a considerable diagnostic value. In the presented material it allowed for the precise determination of localisation of the tumour in 86% of the cases.