Bony eminence on the middle cranial fossa corresponding to the temporomandibular joint

Abstract

We report a nameless bony eminence over the temporomandibular joint (TMJ) and its possible clinical significance. Forty-two half heads of 21 UK Caucasian cadavers (61-95 years old, mean 84.3 +/- 8.2 years, male:female = 11:10) were used to investigate the surface of the middle cranial fossa (MCF) over the TMJ. The thickness of the bony roof of the glenoid fossa was also measured. A bony eminence over the glenoid fossa was observed in half of the specimens. Some showed a complete oval bulge, which completely reflected the contour of the glenoid fossa. The others showed a bony bulge, which partially reflected that contour. The mean (+/-SD) thickness of the bone in the roof of glenoid fossa was 1.5 +/- 1.2 mm. The mean bony thickness of specimens showing the eminence was 0.8 +/- 0.5 mm, whereas it was 2.3 +/- 1.2 mm in specimens without an eminence. These differences were statistically significant (P < 0.01). The osteological features we describe may be relevant to certain clinical problems. Traumatic dislocation of mandibular condyle, for example, might relate to a weakness of the glenoid fossa.