The pneumatic spaces of the temporal bone: relationship to the temporomandibular joint

Objectives: To assess the topographic relationship between the pneumatic sp aces of the temporal bone and the temporomandibular joint (TMJ) using high- resolution CT. Methods: Findings from 100 consecutive patients who had undergone high-reso lution axial CT of the base of the skull were reviewed on a digital imaging workstation, Additional multiplanar reformatted images were created in the sagittal and coronal planes through the TMJ, The extension of the pneumati c spaces of the temporal bone and their relation to the TMJ were determined on both sides. Results: The extent of pneumatisation of the temporal bone varied considera bly. The roof of the TMJ fossa was pneumatised in 51 patients. The articula r eminence contained air spaces in 12 patients, the root of the zygomatic p rocess in five patients. Air cells in the peritubal area extended into the medial wall of the glenoid fossa 53 patients. In approximately 25% the exte nt of pneumatisation showed marked asymmetry. Conclusions: Pneumatisation of the temporal bone frequently extends close t o the TMJ. Knowledge of these air spaces is helpful for the interpretation of imaging studies such as panoramic radiographs and to understand the spre ad of pathological processes into the joint.