<Tr> <Th> FMA </Th> <Td> 75306 </Td> </Tr> <Tr> <Td_colspan="2"> Anatomical terms of bone (edit on Wikidata) </Td> </Tr> <P> The foramen magnum (Latin: great hole) is a large oval opening (foramen) 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 . Apart from the transmission of the medulla oblongata and its membranes, the foramen magnum transmits the vertebral arteries, the anterior and posterior spinal arteries, the tectorial membranes and alar ligaments . It also transmits the spinal component of the accessory nerve into the skull . </P> <P> The opisthion is the midpoint on the posterior margin of the foramen magnum and is a cephalometric landmark . Another landmark is the basion located at the midpoint on the anterior margin of the foramen magnum . </P>

The foramen magnus is a big hole in which of the following bones