Foramen Magnum of occipital boneCheck our Apps3D Heart AnatomyXR Anatomy3D Osteology 3D OsteologyAll visual materials are sourced directly from the app 3D OsteologyLearn MoreThe Foramen Magnum is a hole that provides a passageway for the brainstem, nerves, and vessels. It is encompassed by the four constituent parts of the occipital bone: the Squamous part, the Basilar part, and two Lateral Parts.. (3,7).