In the

occipital bone The occipital bone () is a neurocranium, cranial dermal bone and the main bone of the occiput (back and lower part of the skull). It is trapezoidal in shape and curved on itself like a shallow dish. The occipital bone overlies the occipital lobe ...

, the lower division of the

cruciate eminence The cruciform eminence (or cruciate eminence) divides the deeply concave internal surface of the occipital bone into four fossae: * The upper two fossae are called the cerebral fossae, are triangular and lodge the occipital lobes of the cerebrum. ...

is prominent, and is named the internal occipital crest; it bifurcates near the

foramen magnum The foramen magnum ( la, great hole) is a large, oval-shaped opening in the occipital bone of the skull. 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 oblon ...

and gives attachment to the

falx cerebelli The falx cerebelli is a small sickle-shaped fold of dura mater projecting forwards into the posterior cerebellar notch as well as projecting into the vallecula of the cerebellum between the two cerebellar hemispheres. The name comes from two ...

; in the attached margin of this falx is the

occipital sinus The occipital sinus is the smallest of the dural venous sinuses. It is usually unpaired, and is sometimes altogether absent. It is situated in the attached margin of the falx cerebelli. It commences near the foramen magnum, and ends by draining int ...

, which is sometimes duplicated. In the upper part of the internal occipital crest, a small depression is sometimes distinguishable; it is termed the vermian fossa since it is occupied by part of the

cerebellar vermis The cerebellar vermis (from Latin ''vermis,'' "worm") is located in the medial, cortico-nuclear zone of the cerebellum, which is in the posterior fossa of the cranium. The primary fissure in the vermis curves ventrolaterally to the superior ...

of the

cerebellum The cerebellum (Latin for "little brain") is a major feature of the hindbrain of all vertebrates. Although usually smaller than the cerebrum, in some animals such as the mormyrid fishes it may be as large as or even larger. In humans, the cerebel ...

Additional images

File:Internal occipital crest - animation.gif, Position of internal occipital crest (shown in red). Animation. File:Internal occipital crest - superior view.png, Base of the skull. Internal occipital crest shown in red. File:Gray193 Internal occipital crest.png ,

Base of the skull The base of skull, also known as the cranial base or the cranial floor, is the most inferior area of the skull. It is composed of the endocranium and the lower parts of the calvaria. Structure Structures found at the base of the skull are for ...

. Upper surface. (Internal occipital crest visible below

.) File:Occipital bone 3.jpg, Base of the skull. Internal occipital crest labelled at bottom.

References

External links

* Bones of the head and neck {{musculoskeletal-stub