Foramen magnum 285118 219276457 2008-06-14T12:56:05Z 68.40.238.79 {{Infobox Bone | Name = Foramen magnum | Latin = | GraySubject = 31 | GrayPage = 129 | Image = Gray130.png | Caption = Occipital bone. Inner surface. | System = | MeshName = Foramen+Magnum | MeshNumber = A02.835.232.781.572.434 | }} In [[anatomy]], in the [[occipital bone]], the '''foramen magnum''' (Latin: 'great hole') is one of the several oval or circular apertures in the base of the [[skull]] (the [[Foramina of skull|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 artery|vertebral arteries]], the [[Anterior spinal artery|anterior]] and [[Posterior spinal artery|posterior spinal arteries]], the [[membrana tectoria]] and [[alar ligaments]]. ==Importance== In humans, the foramen magnum is farther underneath the head than in great apes. Thus, in humans, the neck muscles 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 ([[bipedal|bipedality]]) rather than four. The foramen magnum is the border line above which is the brain, and below, the spinal cord. ==Additional images== <gallery> Image:Gray129.png|Occipital bone. Outer surface. Image:Gray187.png|Base of skull. Inferior surface. Image:Gray193.png|Base of the skull. Upper surface. Image:Human brain dura mater (reflections) description.JPG|Human brain dura mater (reflections) </gallery> ==See also== * [[Posterior cranial fossa]] ==External links== * {{SUNYAnatomyFigs|22|4b|10}} * {{NormanAnatomy|cranialnerves}} ({{NormanAnatomyFig|XI}}) * {{RocheLexicon|34257.000-1}} {{Gray's}} {{Skull}} {{Foramina of skull}} [[Category:Head and neck]] [[Category:Foramina of the skull]] {{musculoskeletal-stub}} [[de:Foramen magnum]] [[es:Foramen magnum]] [[it:Foro occipitale]] [[hu:Öreglyuk]] [[pt:Foramen magnum]] [[simple:Foramen magnum]] [[sk:Veľký otvor]] [[sv:Stora nackhålet]] [[th:ฟอราเมน แมกนัม]]