- Foramen magnum
Bone: Foramen magnum 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.
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)..
- SUNY Figs 22:4b-10
- cranialnerves at The Anatomy Lesson by Wesley Norman (Georgetown University) (XI)
- Roche Lexicon - illustrated navigator, at Elsevier 34257.000-1
Bones of head and neck: the neurocranium of the skull (TA A02.1.01–07, GA 2.129–155) OccipitalOther Parietal Frontal Temporal SphenoidSurfacesOther EthmoidPlatesSurfaces
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