[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Anatomy](https://durgical.com/en/anatomy/) › [Head and neck](https://durgical.com/en/anatomy/region/head-and-neck/) › Tentorium [Nervous system](https://durgical.com/en/anatomy/system/nervous-system/) · [Head and neck](https://durgical.com/en/anatomy/region/head-and-neck/) # Tentorium The tentorium cerebelli is a tent-like sheet of dura that separates the cerebellum from the cerebrum above; brain can herniate through its opening. Official name: Tentorium cerebelli [See in 3D →](https://durgical.app/?from=durgipedia&lang=en#region=head_neck&select=tentorium_cerebelli&side=r) Opens in the Durgical app, no sign-up needed. ## What it is A tent of dura between the cerebrum and the cerebellum. ## What it does Its notch is where the temporal lobe can herniate and press on nerve III. ## Key points - Divides the cranial cavity into supratentorial (cerebral hemispheres) and infratentorial (posterior fossa: cerebellum, [pons](https://durgical.com/en/anatomy/pons/), medulla) compartments; brain tumours are classed by this line - Uncal (transtentorial) herniation: the medial temporal lobe slides over the free edge and compresses the oculomotor nerve (dilated pupil, then ptosis, eye down and out) and the posterior cerebral artery - Pushing the opposite cerebral peduncle against the edge (Kernohan notch) gives weakness on the same side as the mass: a false localizing sign ## Key facts **Attaches** Petrous ridges, clinoid processes and the grooves of the transverse sinuses **Function** Dural roof over the cerebellum; its free edge (tentorial notch) surrounds the midbrain; uncal herniation here compresses III ## Relations **Contents** [Straight sinus](https://durgical.com/en/anatomy/straight-sinus/) along its junction with the [falx cerebri](https://durgical.com/en/anatomy/falx-cerebri/), the transverse sinuses in its attached outer border, the superior [petrosal sinuses](https://durgical.com/en/anatomy/superior-petrosal-sinus/) along the petrous ridges **Above** [Occipital lobe](https://durgical.com/en/anatomy/superior-occipital-gyri/) and the lower surface of the [temporal lobe](https://durgical.com/en/anatomy/middle-temporal-gyrus/) **Below** Upper surface of the [cerebellum](https://durgical.com/en/anatomy/anterior-quadrangular-lobule/) **Medial** [Midbrain](https://durgical.com/en/anatomy/midbrain/) in the tentorial notch; the [oculomotor nerve](https://durgical.com/en/anatomy/oculomotor-nerve/) passes forward between the [posterior cerebral artery](https://durgical.com/en/anatomy/posterior-cerebral-artery/) and the [superior cerebellar artery](https://durgical.com/en/anatomy/superior-cerebellar-artery/), and the [trochlear nerve](https://durgical.com/en/anatomy/trochlear-nerve/) runs along the free edge ## How to find it On coronal and sagittal MRI it is the tent-shaped sheet over the cerebellum, bright after contrast. Its outer edge follows the grooves of the transverse sinuses and the upper border of the petrous bone; its free edge forms the tentorial notch around the midbrain, where the oculomotor and trochlear nerves run close to it. ## On imaging Coronal and sagittal MRI show a thin, enhancing tent-shaped sheet; tentorial subdural blood layers along it. On CT, effaced cisterns around the midbrain suggest transtentorial herniation. ## Clinical notes - Compression of the posterior cerebral artery in uncal herniation can cause an occipital infarct with loss of the opposite visual field - Downward displacement of the brainstem through the notch can tear small perforating vessels: Duret haemorrhages in the midbrain and pons - Posterior fossa masses can push the cerebellum upward through the notch or drive the [cerebellar tonsils](https://durgical.com/en/anatomy/tonsil-of-cerebellum/) down into the [foramen magnum](https://durgical.com/en/anatomy/foramen-magnum/) ## Related conditions - [Raised intracranial pressure and brain herniation](https://durgical.com/en/conditions/raised-intracranial-pressure-and-brain-herniation/) - [Subdural haematoma](https://durgical.com/en/conditions/subdural-haematoma/) ## Test yourself Think of the answer, then tap the question to see it. ## Which compartments does the tentorium cerebelli divide the cranial cavity into? Supratentorial (cerebral hemispheres) and infratentorial (posterior fossa: cerebellum, pons, medulla). ## What does uncal herniation over the tentorium compress? The oculomotor nerve (dilated pupil, then ptosis, eye down and out) and the posterior cerebral artery. ## Why can compression of the posterior cerebral artery in uncal herniation cause visual loss? It can cause an occipital infarct with loss of the opposite visual field. [Add to my cards (3)](https://durgical.app/estudiar/?add=/en/anatomy/tentorium-cerebelli/) Educational information, not medical advice. For any symptom, see a health professional. ## Its names **Official Latin (TA2)** tentorium cerebelli TA2 5375 **Official Spanish (DeCS)** Tienda del cerebelo **English (TA2)** Tentorium cerebelli **Also called** cerebellar tentorium ## Related - [Transverse sinus](https://durgical.com/en/anatomy/transverse-sinus/) Sources: Terminologia Anatomica (TA2); [Neuroanatomy, Tentorium Cerebelli](https://www.ncbi.nlm.nih.gov/books/NBK557840/). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/anatomy/tentorium-cerebelli/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/anatomy/tentorium-cerebelli/