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More on Bones and the Skeletal System

Foramen: A foramen is an opening in a bone that allows structures to pass through, such as nerves and blood vessels. The cranium of the skull has many such openings in its floor, most notably the foramen magnum, located on the base of the occipital bone, which allows the spinal cord to pass through. Although the spinal cord is continuous with the brain, it is said to begin at the level of this opening. Other such foramina (plural for foramen) of the cranium are the foramen lacerum, foramen ovale, foramen spinosium, greater palantine foramen, incisive foramen, foramen rotundum, intraorbital foramen, jugular foramen, mandibular foramen, and others. See The Axial Skeleton for more information about the skull. A foramen is sometimes referred to as a canal when it is a narrow tube, channel, or passageway rather than just an opening.

The image below shows the foramen magnum at the base of the skull and also the spinal nerves colored red. There are also glimpses of the brain through the foramen magnum and through other passages of the inferior skull.

animated image of the base of the skull showing foramen magnum on occipital bone and spinal nerves exiting the foramen magnum colored red and brain tissue colored brown

Foramen Magnum with Spinal Nerves Colored Red

The next image is a labelled view of the inner cranial vault, with many bones and foramen labelled.

photo on interior vault of cranium (inside of top of skull) with many bones and foramen labelled including the olfactory, cecum, ovale, lacerum, jugular, magnum, optic canal, sella turcica, spinosum, crista galli, occipital bone, sphenoid bone, parietal bone, spenoid bone, and frontal bone

Labelled Interior Vault of Cranium Showing Different Foramen
image by Didier Descouens via wikimedia

This page created 22 Oct 2012 01:09
Last updated 18 Jul 2016 19:32

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