The cerebellar tentorium or tentorium cerebelli (

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

for "tent of the

cerebellum The cerebellum (: cerebella or cerebellums; 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 it or eve ...

") is one of four dural folds that separate the

cranial cavity The cranial cavity, also known as intracranial space, is the space within the skull that accommodates the brain. The skull is also known as the cranium. The cranial cavity is formed by eight cranial bones known as the neurocranium that in human ...

into four (incomplete) compartments. The cerebellar tentorium separates the

from the

cerebrum The cerebrum (: cerebra), telencephalon or endbrain is the largest part of the brain, containing the cerebral cortex (of the two cerebral hemispheres) as well as several subcortical structures, including the hippocampus, basal ganglia, and olfac ...

forming a supratentorial and an infratentorial region; the cerebrum is supratentorial and the cerebellum infratentorial. The free border of the tentorium gives passage to the

midbrain The midbrain or mesencephalon is the uppermost portion of the brainstem connecting the diencephalon and cerebrum with the pons. It consists of the cerebral peduncles, tegmentum, and tectum. It is functionally associated with vision, hearing, mo ...

(the upper-most part of the

brainstem The brainstem (or brain stem) is the posterior stalk-like part of the brain that connects the cerebrum with the spinal cord. In the human brain the brainstem is composed of the midbrain, the pons, and the medulla oblongata. The midbrain is conti ...

Structure

Free border

The free border of the tentorium is U-shaped; it forms an aperture - the tentorial notch (tentorial incisure) - which gives passage to the

. The free border of each side extends anteriorly beyond the medial end of the superior petrosal sinus (i.e. the apex of the petrous part of the temporal bone) to overlap the attached margin, thenceforth forming a ridge of dura matter upon the roof of the

cavernous sinus The cavernous sinus within the human head is one of the dural venous sinuses creating a cavity called the lateral sellar compartment bordered by the temporal bone of the skull and the sphenoid bone, lateral to the sella turcica. Structure The ...

, terminating anteriorly by attaching at the anterior clinoid process. The tentorium slopes superior-ward so that the free border is situated at a more superior level than its bony attachment, thus conforming to the shape of the surfaces of the cerebrum and cerebellum with which it is in contact.

Attached border

The attached margin of the tentorium cerebelli is attached at the edges of the transverse sinuses and superior petrosal sinus (here, the two layers of the tentorium diverge to embrace the sinuses); it thus attaches onto 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 lies over the occipital lob ...

posteriorly, and (the superior angle of) the petrous part of the

temporal bone The temporal bone is a paired bone situated at the sides and base of the skull, lateral to the temporal lobe of the cerebral cortex. The temporal bones are overlaid by the sides of the head known as the temples where four of the cranial bone ...

anteriorly. Anteriorly, its attachment extends to the posterior clinoid processes; posteriorly, it extends to the internal occipital protuberance. It is attached, behind, by its convex border, to the transverse ridges upon the inner surface of the

, and there encloses the transverse sinuses; in front, to the superior angle of the petrous part of the

on either side, enclosing the superior petrosal sinuses.

Relations

The posterior end of the falx cerebri attaches onto the midline of the upper surface of the tentorium; the straight sinus runs along this line of junction.

Clinical significance

Brain tumor A brain tumor (sometimes referred to as brain cancer) occurs when a group of cells within the Human brain, brain turn cancerous and grow out of control, creating a mass. There are two main types of tumors: malignant (cancerous) tumors and benign ...

s 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 o ...

. 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.

Calcification Calcification is the accumulation of calcium salts in a body tissue. It normally occurs in the formation of bone, but calcium can be deposited abnormally in soft tissue,Miller, J. D. Cardiovascular calcification: Orbicular origins. ''Nature M ...

s within the cerebellar tentorium are not very common in elderly people; they are not accompanied by any disease and have no known cause.

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

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