Anatomical Variations of Foramen Ovale and Clinical Significance

INTRODUCTION: The foramen ovale is present in sphenoid bone which transmits the mandibular nerve, accessory meningeal artery, emissary vein and the lesser petrosal nerve. MATERIALS & METHODS: This study was conducted on a total 100 sides in 50 dry adult skulls. The shape of foramen will be determined by a visual examination. Margins of foramen were carefully observed for the abnormal bony outgrowths such as sharp bony projections (spine), small blunt bony projection (tubercle), bony plate and bony bar. RESULTS: We observed the variations in shape of foramen ovale. We found oval, almond, round, triangular, slit like and irregular shaped in 62 %, 20 %, 9 %, 4 %, 3 % and 2 % foramina ovale respectively. We also observed abnormal bony outgrowths in the foramen ovale like spines, tubercles, bony plate and bony bar. Abnormal bony bar was dividing the foramen ovale in 2 compartments (Anterior and Posterior). CONCLUSIONS: The precise knowledge of variations of foramen ovale is of valuable contribution for neurosurgeons to development of new and different techniques to approach the middle cranial fossa. In our study we found, 100 % tubercles and 80 % spines were arising from anterior margin of foramen ovale. These findings are important for neurosurgeons to approach middle cranial fossa via foramen ovale for neurosurgical and diagnostic procedures like percutaneous biopsy of cavernous sinus tumours, electroencephalographic analysis, microvascular decompression, percutaneous trigeminal rhizotomy and administration of anaesthesia to the mandibular nerve. Surgeons should avoid to go, close to the anterior margin of foramen ovale as spines and tubercles could interrupt the procedures.