[The peculiarities of petrotympanic fissure topography in Costen syndrome and possible causes of its development].

A complex study of morphometric characteristics of the articular surfaces of the temporomandibular joint and the examination of the peculiarities of the petrotympanic fissure topography were performed on 138 samples of skulls of adult individuals with intact occlusion, complete anodontia and different forms of cranial skull (dolicho-, meso- and brachicranial). No distinct differences in studied parameters were found between the studied groups. However, in the hypsicranial group the petrotympanic fissure was found to pass more often through the medial third of the mandibular fossa, which may be a predisposing anatomical factor for Costen syndrome. Due to the fact that in anodontia the parameters characterizing the articular surfaces of the temporomandibular joint, are significantly changed, the immediate cause of the Costen syndrome are the changes of the articular surfaces of the temporomandibular joint, primarily the reduction in the size of mandibular condyle, which is accompanied by its pathological displacement and compression of the chorda tympani.