The cerebellar tentorium or tentorium cerebelli ( Latin for "tent 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 ...

") is an extension of the dura mater that separates the cerebellum from the inferior portion of the occipital lobes.

Structure

The cerebellar tentorium is an arched lamina, elevated in the middle, and inclining downward toward the circumference. It covers the top of the

, and supports the

occipital lobes The occipital lobe is one of the four major lobes of the cerebral cortex in the brain of mammals. The name derives from its position at the back of the head, from the Latin ''ob'', "behind", and ''caput'', "head". The occipital lobe is the v ...

of the brain. Its anterior border is free and concave, and bounds a large oval opening, the

tentorial incisure The tentorial notch (also known as the tentorial incisure or incisura tentorii) refers to the anterior opening between the free edge of the cerebellar tentorium and the Clivus (anatomy), clivus for the passage of the brainstem. The midbrain cont ...

, through which pass the cerebral peduncles. It is attached, behind, by its convex border, to the transverse ridges upon the inner surface of 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 ...

, and there encloses the transverse sinuses; in front, to the superior angle of the petrous part of the temporal bone on either side, enclosing the superior petrosal sinuses. At the apex of the petrous part of the temporal bone the free and attached borders meet, and, crossing one another, are continued forward to be fixed to the

anterior Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...

and posterior clinoid processes (respectively) of the

sphenoid bone The sphenoid bone is an unpaired bone of the neurocranium. It is situated in the middle of the skull towards the front, in front of the basilar part of occipital bone, basilar part of the occipital bone. The sphenoid bone is one of the seven bones ...

. To the middle line of its upper surface the posterior border of the falx cerebri is attached, the straight sinus being placed at their line of junction.

Clinical significance

Brain tumors are often characterized as supratentorial (above the tentorium) and infratentorial (below the tentorium). The location of the tumor can help in determining the type of tumor, as different tumors occur with different frequencies at each location. Additionally, most childhood primary brain tumors are infratentorial, while most adult primary brain tumors are supratentorial. The location of the tumor may have prognostic significance as well. Since the tentorium is a hard structure, if there is an expansion of the volume of the brain or its surrounding matter above the tentorium, such as because of a tumour or bleeding, the brain can get pushed down partly through the tentorium. This is called herniation and will often cause an enlarged pupil on the affected side, due to pressure on the

oculomotor nerve The oculomotor nerve, also known as the third cranial nerve, cranial nerve III, or simply CN III, is a cranial nerve that enters the orbit through the superior orbital fissure and innervates extraocular muscles that enable most movements of ...

. Tentorial herniation is a serious symptom, especially since the brainstem is likely to be compressed as well if the intracranial pressure rises further. A common type of herniation is uncal herniation. Calcifications within the cerebellar tentorium are relatively common in elderly people; they seem to rarely cause symptoms.

Additional images

File:Falxcerebri.jpg, Dura mater and its processes exposed by removing part of the right half of the skull, and the brain. File:Sobo 1909 589.png , Tentorium cerebelli seen cut out in the back of the skull. File:Gray568.png, Sagittal section of the skull, showing the sinuses of the dura. File:Human brain dura mater (reflections) description.JPG, Human brain dura mater (reflections) File:Tentorum cerebelli.jpg, Tentorium cerebelli

References

External links

Photo
at Indiana University * {{Authority control Meninges