The accessory foramen ovale of the skull: an osteological study.

The sphenoid bone is known to have several foramina and the foramen ovale is one amongst them. The foramen ovale transmits the mandibular nerve, accessory meningeal artery, lesser petrosal nerve and the emissary veins. There have been past reports on the variations of the different foramina present in the skull but there are no reports on the variations of the skull foramina from any of the South-East Asian countries. The present study aims to highlight the presence of an accessory foramen ovale in the skull in Malaysian population. Both sides of fifteen adult skulls (n = 30) were taken for observation of any variations in the foramen ovale. We observed the presence of accessory foramen ovale on the left side of a single skull (3.33%). The minute accessory foramen ovale was located 0.1 cm medial to the normal foramen ovale. The anomalous accessory foramen ovale was circular in shape and measured 0.1 cm in diameter. Anatomical knowledge of the foramen ovale is important for all neurosurgical procedures involving the trigeminal nerve and administration of anaesthesia in the mandibular nerve. Interestingly, the percutaneous biopsy of the cavernous sinus is also performed through the foramen ovale. Prior knowledge of the presence of an accessory foramen ovale may be important for academic, anthropological, forensic and clinical purpose and the present study aims to highlight such.