The temporomandibular joint: pneumatic temporal cells open into the articular and extradural spaces

The pneumatisation of the articular tubercle (PAT) of the temporal squama isa rare condition that modifies the barrier between the temporomandibular joint(TMJ) space and the middle cranial fossa. During a routine examination of thecone-beam computed tomography (CBCT) files of patients who were scannedfor dental medical purposes, we identified a case with multiple rare anatomicvariations. First, the petrous apex was bilaterally pneumatised. Moreover, bilateraland multilocular PAT were observed, while on one side it was further found thatthe pneumatic cells were equally dehiscent towards the extradural space and thesuperior joint space. To the best of our knowledge, such dehiscence has not previouslybeen reported. The two temporomastoid pneumatisations were extendedwith occipital pneumatisations of the lateral masses and occipital condyles, thelatter being an extremely rare evidence. The internal dehiscence of the mandibularcanal in the right ramus of the mandible was also noted. Additionally, doublemental foramen and impacted third molars were found on the left side. Suchmultilocular PAT represents a low-resistance pathway for the bidirectional spreadof fluids through the roof of the TMJ. Further, it could add to a morphologicalpicture of hyperpneumatisation of the posterior cranial fossa floor, which couldsignify the involvement of the last four cranial nerves in the clinical picture of TMJpain.