opening (foramen) in the occipital bone of the skull. It is present in humans, and in many other animals. Anteriorly, it is bounded by the basiocciput. Posteriorly, it is bounded by the supraocciput. Laterally, it is bounded by the occipital condyles.

On the occipital bone, the foramen magnum presents two midline cephalometric landmarks. The opisthion