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With the foramen magnum being position anterior in the cranium, the body of bipedal mammals is given a different center of gravity compared to quadrupedal mammals. The anterior foramen magnum shifts the weight of the body more to the mammals' pelvis and femur, present in some primates, like great apes.
The foramen magnum is located inferiorly under the skull, which puts much of the weight of the head behind the spine. The flat human face helps to maintain balance on the occipital condyles . Because of this, the erect position of the head is possible without the prominent supraorbital ridges and the strong muscular attachments found in, for ...
The condyles are oval or reniform (kidney-shaped) in shape, and their anterior extremities, directed forward and medialward, are closer together than their posterior, and encroach on the basilar portion of the bone; the posterior extremities extend back to the level of the middle of the foramen magnum.
The skull was an indicator of orthograde posture because of the location and orientation of the foramen magnum. The foramen magnum is the space in the skull that acts as the bridge to the central nervous system from the spinal cord to the brain. For animals with "pronograde posture, the foramen magnum is dorsally oriented, whereas in humans it ...
A further plate composed of four pairs of bones forms the roof of the mouth; these include the vomer and palatine bones. The base of the cranium is formed from a ring of bones surrounding the foramen magnum and a median bone lying further forward; these are homologous with the occipital bone and parts of the sphenoid in mammals. Finally, the ...
On its lower surface, about 1 cm. in front of the foramen magnum, is the pharyngeal tubercle which gives attachment to the fibrous raphe of the pharynx.. On either side of the middle line the longus capitis and rectus capitis anterior are inserted, and immediately in front of the foramen magnum the anterior atlantooccipital membrane is attached.
The posterior cranial fossa is the part of the cranial cavity located between the foramen magnum, and tentorium cerebelli. It is formed by the sphenoid bones, temporal bones, and occipital bone. It lodges the cerebellum, and parts of the brainstem.
Below the neurocranium is a complex of openings and bones, including the foramen magnum which houses the neural spine. The auditory bullae, located in the same region, aid in hearing. [7] The size of the neurocranium is variable among mammals. The roof may contain ridges such as the temporal crests.