Foramen ovale

Two structures in the human body are called foramen ovale, meaning circular hole.

In the fetal heart the foramen ovale allows blood to enter the left atrium of the heart from the right atrium. Normally this opening closes in the first year of life, however in about 30% of adults a small patent foramen ovale is still present.

At the base of the skull the foramen ovale is a hole that transmits the mandibular nerve, the otic ganglion , the accessory meningeal artery , emissary veins (from the cavernous sinus to the pterygoid plexus ) and the lesser superficial petrosal nerve.