[Roentgen diagnosis of fracture of the calcaneus with involvement of the lower ankle joint].

The prognosis and therapy of the fracture of the calcaneum largely depend on an involvement of the talo-calcaneonavicular joint. Incongruities and grated fractures in the region of the posterior joint facet are prognostically unfavourable but can be tackled by surgery. Standard X-ray films of the calcaneonavicular joint and of the tarsus do not offer sufficiently conclusive criteria. Oblique X-ray films with 60 degree internal and external rotation visualise the talo-calcaneonavicular joint almost free from overshadowing. The diagnostic value and technique of the standard and oblique X-ray films, as well as the topography of the joint facets under different projections, are demonstrated in this article by means of X-ray films of preparations and by case reports.