Main Page | See live article | Alphabetical index In anatomy, the foramen magnum is the large hole in the occipital bone in the base of the skull, through which the medulla oblongata (an extension of the spinal cord) exits the skull vault. In humans the foramen magnum is farther underneath the head than in great apes. Thus, the neck muscles do not need to be as robust in order to hold the head upright. This is a stub article. This article is from Wikipedia. All text is available under the terms of the GNU Free Documentation License.