Foramen Magnum

Foramen Magnum is a large oval opening in the occipital bone of the skull in humans and various other animals. It is one of the several oval or circular openings (foramina) in the base of the skull. The spinal cord, an extension of the medulla, passes through the foramen magnum as it exits the cranial cavity.

Anatomy

The foramen magnum is situated in the anterior part of the occipital bone. It is oval in shape and its longest diameter is anteroposterior (from front to back). The foramen magnum is larger in males than in females, which can help in determining sex in forensic investigations.

Function

The foramen magnum serves as a conduit for the medulla oblongata (an extension of the spinal cord) which connects the brain to the spinal cord, and the meninges, which are membranes that envelop the brain and spinal cord. It also allows passage for the vertebral arteries, the anterior and posterior spinal arteries, the tectorial membranes and alar ligaments.

Clinical significance

The size and shape of the foramen magnum is significant in the study of human evolution, and it also has clinical importance in terms of conditions such as Chiari malformation, where part of the brain descends into the spinal canal through the foramen magnum.

See also

• Occipital bone
• Spinal cord
• Medulla oblongata
• Chiari malformation

References

Foramen Magnum Resources
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