Foramen magnum


Foramen magnum
Bone: Foramen magnum
Gray130.png
Occipital bone. Inner surface.
Gray's subject #31 129
MeSH Foramen+Magnum

In anatomy, the foramen magnum (Latin: 'great hole') is a large opening in the occipital bone of the cranium. It is one of the several oval or circular apertures in the base of the skull (the foramina), 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.

Contents

Importance

In humans, the foramen magnum is farther underneath the head than in other great apes. Thus, in humans, the neck muscles (including the occipitofrontalis muscle) do not need to be as robust in order to hold the head upright. Comparisons of the position of the foramen magnum in early hominid species are useful to determine how comfortable a particular species was when walking on two limbs (bipedalism) rather than four (quadrupedalism)..

Additional images

Occipital bone. Outer surface.  
Base of skull. Inferior surface.  
Base of the skull. Upper surface.  
Human brain dura mater (reflections)  

See also

External links

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.


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  • Foramen magnum — Saltar a navegación, búsqueda Foramen magnum es el nombre del orificio mayor situado en la parte pósteroinferior del cráneo (base del cráneo, piso témporo occipital), a través del cual se establece la continuidad del sistema nervioso central… …   Wikipedia Español

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  • Foramen magnum — es el nombre del orificio en la parte inferior del cráneo, a través del cual el extremo de la espina dorsal se inserta en el cerebro. En la evolución del hombre, mientras mas abajo estuviera el foramen magnum, mas erguida era la posicion de la… …   Enciclopedia Universal

  • foramen magnum — [mag′nəm] n. [ModL, large opening] the opening at the base of the skull where the spinal cord merges with the medulla oblongata …   English World dictionary

  • Foramen magnum — Os occipital Vue interne …   Wikipédia en Français

  • Foramen magnum — The large hole at the base of the skull which allows passage of the spinal cord. * * * foramen mag·num mag nəm n the opening in the skull through which the spinal cord passes to become the medulla oblongata * * * [TA] the large opening in the… …   Medical dictionary

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