The vascular compression of a nerve is known to be the most important cause of idiopathic trigeminal neuralgia (ITN) by most authors. However, several cases of skull base deformities in patients with ITN have been reported in our bibliographic review. AIM. To compare the existence of platybasia between a group of patients with ITN and a randomized control group.Twenty-five patients with ITN and twenty-five control subjects were X-rayed and their basal angles were measured and compared.The basal angle measured to investigate the existence of platybasia is significantly greater in the ITN group than in the control group. Platybasia was found in 10 patients with ITN. However, only two cases of platybasia were reported in the control group. Therefore in our study we have found that the incidence of platybasia in patients with ITN is significantly increased.Our data demonstrated that platybasia has an important role in the pathogenesis of the ITN by altering the normal anatomy of the nerves and vessels within the posterior fossa.