Tentorial notch | |
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Details | |
Part of | Tentorium cerebelli |
Identifiers | |
Latin | incisura tentorii |
TA98 | A14.1.01.105 |
TA2 | 5376 |
FMA | 306052 |
Anatomical terms of neuroanatomy |
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 for the passage of the brainstem. [1] [2]
The midbrain continues with the thalamus of the diencephalon through the tentorial notch. [3]
The tentorial notch is located between the tentorial edges and communicates the supratentorial and infratentorial spaces. This area can be divided into three spaces: anterior, middle (lateral to), and posterior to the brainstem. The middle incisural space is close to the midbrain and the upper pons at the level of the pontomesencephalic sulcus. Medial temporal lobe structures such as the uncus, the parahippocampal gyrus and the hippocampal formation, are also intimately related to the incisura. The principal vascular structures coursing along the middle incisural space are the posterior cerebral artery and the superior cerebellar artery which pass around the brainstem, parallel to the free tentorial edge. The incisura has also a close relationship with the first 6 cranial nerves. [4]
If intracranial pressure superior to the cerebellar tentorium is increased, it may force part of the temporal lobe through this notch. This is referred to as a tentorial brain herniation. The consequences are unconsciousness, widening of the pupil of the affected side, and hemiparesis on the opposite side.
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The pons is part of the brainstem that in humans and other mammals, lies inferior to the midbrain, superior to the medulla oblongata and anterior to the cerebellum.
The brainstem is the stalk-like part of the brain that connects the forebrain with the spinal cord. In the human brain, the brainstem is composed of the midbrain, the pons, and the medulla oblongata. The midbrain is continuous with the thalamus of the diencephalon through the tentorial notch.
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 the eye and that raise the eyelid. The nerve also contains fibers that innervate the intrinsic eye muscles that enable pupillary constriction and accommodation. The oculomotor nerve is derived from the basal plate of the embryonic midbrain. Cranial nerves IV and VI also participate in control of eye movement.
The trochlear nerve, also known as the fourth cranial nerve, cranial nerve IV, or CN IV, is a cranial nerve that innervates a single muscle - the superior oblique muscle of the eye. Unlike most other cranial nerves, the trochlear nerve is exclusively a motor nerve.
The midbrain or mesencephalon is the rostral-most portion of the brainstem connecting the diencephalon and cerebrum with the pons. It consists of the cerebral peduncles, tegmentum, and tectum.
The internal capsule is a white matter structure situated in the inferomedial part of each cerebral hemisphere of the brain. It carries information past the basal ganglia, separating the caudate nucleus and the thalamus from the putamen and the globus pallidus. The internal capsule contains both ascending and descending axons, going to and coming from the cerebral cortex. It also separates the caudate nucleus and the putamen in the dorsal striatum, a brain region involved in motor and reward pathways.
The subarachnoid cisterns are spaces formed by openings in the subarachnoid space, an anatomic space in the meninges of the brain. The space is situated between the two meninges, the arachnoid mater and the pia mater. These cisterns are filled with cerebrospinal fluid (CSF).
The cerebellar tentorium or tentorium cerebelli is one of four dural folds that separate the cranial cavity into four (incomplete) compartments. The cerebellar tentorium separates the cerebellum from the cerebrum forming a supratentorial and an infratentorial region; the cerebrum is supratentorial and the cerebellum infratentorial.
Brain herniation is a potentially deadly side effect of very high pressure within the skull that occurs when a part of the brain is squeezed across structures within the skull. The brain can shift across such structures as the falx cerebri, the tentorium cerebelli, and even through the foramen magnum. Herniation can be caused by a number of factors that cause a mass effect and increase intracranial pressure (ICP): these include traumatic brain injury, intracranial hemorrhage, or brain tumor.
The posterior cerebral artery (PCA) is one of a pair of cerebral arteries that supply oxygenated blood to the occipital lobe, part of the back of the human brain. The two arteries originate from the distal end of the basilar artery, where it bifurcates into the left and right posterior cerebral arteries. These anastomose with the middle cerebral arteries and internal carotid arteries via the posterior communicating arteries.
The superior cerebellar artery (SCA) is an artery of the head. It arises near the end of the basilar artery. It is a branch of the basilar artery. It supplies parts of the cerebellum, the midbrain, and other nearby structures. It is the cause of trigeminal neuralgia in some patients.
Duret haemorrhages are small linear areas of bleeding in the midbrain and upper pons of the brainstem. They are caused by a traumatic downward displacement of the brainstem.
The middle cranial fossa is formed by the sphenoid bones, and the temporal bones. It lodges the temporal lobes, and the pituitary gland. It is deeper than the anterior cranial fossa, is narrow medially and widens laterally to the sides of the skull. It is separated from the posterior cranial fossa by the clivus and the petrous crest.
The posterior clinoid processes are the tubercles of the sphenoid bone situated at the superior angles of the dorsum sellæ which represents the posterior boundary of the sella turcica. They vary considerably in size and form. The posterior clinoid processes deepen the sella turcica, and give attachment to the tentorium cerebelli, and the dura forming the floor of the hypophyseal fossa.
The uncus is an anterior extremity of the parahippocampal gyrus. It is separated from the apex of the temporal lobe by a slight fissure called the incisura temporalis.
The interpeduncular cistern is the subarachnoid cistern situated between the dorsum sellae (anteriorly) and the two cerebral peduncles of the mesencephalon (midbrain). Its roof is represented by the floor of the third ventricle. Its floor is formed by the arachnoid membrane extending between the temporal lobes of either side. Anteriorly, it extends to the optic chiasm.
The quadrigeminal cistern is a subarachnoid cistern situated between splenium of corpus callosum, and the superior surface of the cerebellum. It contains a part of the great cerebral vein, the posterior cerebral artery, quadrigeminal artery, glossopharyngeal nerve, and the pineal gland.
Pacchionian foramen means: