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

The pneumatisation of the articular tubercle (PAT) of the temporal squama is a rare condition that modifies the barrier between the temporomandibular joint (TMJ) space and the middle cranial fossa. During a routine examination of the cone-beam computed tomography (CBCT) files of patients who were scanned for dental medical purposes, we identified a case with multiple rare anatomic variations. First, the petrous apex was bilaterally pneumatised. Moreover, bilateral and multilocular PAT were observed, while on one side it was further found that the pneumatic cells were equally dehiscent towards the extradural space and the superior joint space. To the best of our knowledge, such dehiscence has not previously been reported. The two temporomastoid pneumatisations were extended with occipital pneumatisations of the lateral masses and occipital condyles, the latter being an extremely rare evidence. The internal dehiscence of the mandibular canal in the right ramus of the mandible was also noted. Additionally, double mental foramen and impacted third molars were found on the left side. Such multilocular PAT represents a low-resistance pathway for the bidirectional spread of fluids through the roof of the TMJ. Further, it could add to a morphological picture of hyperpneumatisation of the posterior cranial fossa floor, which could signify the involvement of the last four cranial nerves in the clinical picture of TMJ pain.