The posterior or tubal sphenoidal plate extending into the tympanosquamous fissure - A novel finding.

Objective: The tympanic plate typically joins the articular tubercle in the medial glenoid wall. It is aimed to report a peculiar anatomic variant of the latter.

Methods: The computed tomography scans of two adult male cases were documented for the anatomical details of the temporomandibular joint.

Results: The absence of the tubal processes of the tympanic plates was found bilaterally. The medial glenoid walls were penetrated by posterior or tubal sphenoidal plates extending posteriorly from the sphenoidal spines, 6.6 mm/12.2 mm on the right/left sides in the first case, and 9.8/8.4 mm on the right/left sides in the second case. These plates formed the lateral tubal walls and modified the tubal sulci on the sphenopetrosal fissures into musculotubal pseudo-canals. On the sides of the tubal sphenoidal plates formed in the medial wall of the glenoid fossa additional fissures, an anterolateral sphenotemporal one and a postero-medial sphenotympanic one.

Conclusion: As far as the authors know, the tubal plate of the sphenoid bone was not observed previously to participate in the glenoid fossa's medial wall. It could be regarded as a rare anatomic variation.