foramen magnum

In anatomy, in the occipital bone, the foramen magnum is one of the several oval or circular apertures in the base of the skull, through which the medulla oblongata (an extension of the spinal cord) enters and exits the skull vault. Apart from the transmission of the medulla oblongata and its membranes, the foramen magnum transmits the Spinal Accessory nerve, vertebral arteries, the anterior and posterior spinal arteries, the membrana tectoria and alar ligaments. [WP,unvetted]. Every claim on this page comes from the Leumas anatomy graph and carries its source.

What the foramen magnum is

In anatomy, in the occipital bone, the foramen magnum is one of the several oval or circular apertures in the base of the skull, through which the medulla oblongata (an extension of the spinal cord) enters and exits the skull vault. Apart from the transmission of the medulla oblongata and its membranes, the foramen magnum transmits the Spinal Accessory nerve, vertebral arteries, the anterior and posterior spinal arteries, the membrana tectoria and alar ligaments. [WP,unvetted]. The atlas records it as a bone at the organ scale in the human body.

Where the foramen magnum is

It sits in the head, within the skeletal system. Not positioned individually, and containment is not asserted either. Drawn near structures of the same kind, which is a weak claim about location.

What the foramen magnum connects to

The atlas records 4 typed relationships for it, across 4 kinds of connection. a kind of foramen of skull.

Supply and innervation

This dataset asserts no arterial supply, venous drainage or innervation for the foramen magnum. Only a minority of structures carry those edges here, so an empty answer means nothing has been recorded — not that there is nothing to record.

Source

Uberon multi-species anatomy ontology (Mungall et al.), CC BY 4.0. Term UBERON:0003687, version 2026-06-19, retrieved 2026-08-24. Licence: CC-BY-4.0.

• A kind of: foramen of skull.
• located in: occipital bone.
• transports: medulla oblongata.
• surrounded by: occipital bone.

Questions

Where is the foramen magnum?

It sits in the head, within the skeletal system. Not positioned individually, and containment is not asserted either. Drawn near structures of the same kind, which is a weak claim about location.

What does the foramen magnum connect to?

A kind of: foramen of skull.

Is the foramen magnum the same in other species?

Leumas holds the same relationship vocabulary for every species it carries, so where another dataset records this structure you can put the two side by side on /compare.