collection of blood between the dura mater and the arachnoid
Dura mater


V1, V2 and V3). The innervation for the infratentorial dura mater are via upper cervical nerves. Many medical conditions involve the dura mater. A subdural hematoma occurs when there is an abnormal collection of blood between the dura and the arachnoid, usually as a result of torn bridging veins secondary to head trauma. An epidural hematoma is a collection of blood between the dura and the inner surface of the skull, and is usually due to arterial bleeding. Intradural procedures, such as removal of a brain tumour, or treatment
3451614
Meninges


at different points along the subarachnoid space; these are the subarachnoid cisterns, which are filled with cerebrospinal fluid. The dura mater is attached to the skull, whereas in the spinal cord, the dura mater is separated from the vertebrae by a space called the epidural space, which contains fat and blood vessels. The arachnoid is attached to the dura mater, while the pia mater is attached to the central nervous system tissue. When the dura mater and the arachnoid separate through injury or illness, the space between them is the
14808693
Arachnoid mater


into its sulci (folds), as does the pia mater, with the exception of the longitudinal fissure, which divides the left and right cerebral hemispheres. Cerebrospinal fluid (CSF) flows under the arachnoid in the subarachnoid space. The arachnoid mater makes arachnoid villi, small protrusions through the dura mater into the venous sinuses of the brain, which allow CSF to exit the subarachnoid space and enter the blood stream. The arachnoid mater and dura mater are very close together throughout the cranium and spinal canal all the way to S2
889365
Meninges


capillaries in the pia mater. It is composed of dense fibrous tissue, and its inner surface is covered by flattened cells like those present on the surfaces of the pia mater and arachnoid mater. The dura mater is a sac that envelops the arachnoid mater and surrounds and supports the large dural sinuses carrying blood from the brain toward the heart. The dura has four areas of infolding: The middle element of the meninges is the arachnoid mater, so named because of its spider web-like appearance. It cushions the central nervous
14808688
Arachnoid mater


, where the two layers fuse into one and end in the filum terminale, which attaches to the coccygeal end of the spinal canal. Sandwiched between the dura and arachnoid maters lie some veins that connect the brain's venous system with the venous system in the dura mater. The arachnoid mater covering the brain is referred to as the "arachnoidea encephali," and the portion covering the spinal cord as the "arachnoidea spinalis." The arachnoid and pia mater are sometimes considered as a single structure, the leptomeninx, or the
889366
Arachnoid mater


The arachnoid mater is one of the three meninges, the protective membranes that cover the brain and spinal cord. The arachnoid mater is a derivative of the neural crest mesectoderm in the embryo. It is interposed between the two other meninges, the more superficial and much thicker dura mater and the deeper pia mater, from which it is separated by the subarachnoid space. The delicate arachnoid layer is not attached to the inside of the dura but against it and surrounds the brain and spinal cord. It does not line the brain down
889364
Epidural administration


, as compared with early initiation of analgesia with parenteral opioids. The epidural space is the space inside the bony spinal canal but just outside the dura mater ("dura"). In contact with the inner surface of the dura is another membrane called the arachnoid mater ("arachnoid"). The cerebrospinal fluid that surrounds the spinal cord is contained by the arachnoid mater. In adults, the spinal cord terminates around the level of the disc between L1 and L2 (in neonates it extends to L3 but can reach as
11373683
Spinal cord


the dura mater and the surrounding bone of the vertebrae is a space called the epidural space. The epidural space is filled with adipose tissue, and it contains a network of blood vessels. The arachnoid mater, the middle protective layer, is named for its open, spiderweb-like appearance. The space between the arachnoid and the underlying pia mater is called the subarachnoid space. The subarachnoid space contains cerebrospinal fluid (CSF), which can be sampled with a lumbar puncture, or "spinal tap" procedure. The delicate
7480428
Dural venous sinuses


The dural venous sinuses (also called dural sinuses, cerebral sinuses, or cranial sinuses) are venous channels found between the endosteal and meningeal layers of dura mater in the brain. They receive blood from the cerebral veins, receive cerebrospinal fluid (CSF) from the subarachnoid space via arachnoid granulations, and mainly empty into the internal jugular vein. The walls of the dural venous sinuses are composed of dura mater lined with endothelium, a specialized layer of flattened cells found in blood vessels. They differ from other blood vessels in that
3085667
Meninges


The meninges (, "singular:" meninx ( or ), from , "adjectival:" meningeal ) are the three membranes that envelop the brain and spinal cord. In mammals, the meninges are the dura mater, the arachnoid mater, and the pia mater. Cerebrospinal fluid is located in the subarachnoid space between the arachnoid mater and the pia mater. The primary function of the meninges is to protect the central nervous system. The dura mater () (also rarely called "meninx fibrosa" or "pachymeninx"
14808686
Subdural space


The subdural space (or subdural cavity) is a potential space that can be opened by the separation of the arachnoid mater from the dura mater as the result of trauma, pathologic process, or the absence of cerebrospinal fluid as seen in a cadaver. In the cadaver, due to the absence of cerebrospinal fluid in the subarachnoid space, the arachnoid mater falls away from the dura mater. It may also be the site of trauma, such as a subdural hematoma, causing abnormal separation of dura and arachnoid mater. Hence,
889187
Dura mater


Dura mater is a thick membrane made of dense irregular connective tissue that surrounds the brain and spinal cord. It is the outermost of the three layers of membrane called the meninges that protect the central nervous system. The other two meningeal layers are the arachnoid mater and the pia mater. The dura surrounds the brain and the spinal cord and is responsible for keeping in the cerebrospinal fluid. It is derived from neural crest cells. The dura mater has several functions and layers. The dura mater is a membrane that envelops the arachnoid
3451608
Arachnoid granulation


Arachnoid granulations (also arachnoid villi, and pacchionian granulations or bodies) are small protrusions of the arachnoid mater (the thin second layer covering the brain) into the outer membrane of the dura mater (the thick outer layer). They protrude into the dural venous sinuses of the brain, and allow cerebrospinal fluid (CSF) to exit the subarachnoid space and enter the blood stream. The largest granulations lie along the superior sagittal sinus, a large venous space running from front to back along the center of the head (on
4174806
Meninges


portion (arachnoid barrier cell layer) with tightly packed cells and no extracellular collagen; that is why it is considered to represent an effective morphological and physiological meningeal barrier between the cerebrospinal fluid and subarachnoid space and the blood circulation in the dura. The arachnoid barrier layer is characterized by a distinct continuous basal lamina on its inner surface toward the innermost collagenous portion of the arachnoid reticular layer. The pia mater () is a very delicate membrane. It is the meningeal envelope that firmly adheres to the surface of the brain and spinal
14808690
Dura mater


the internal jugular vein. Arachnoid villi, which are outgrowths of the arachnoid mater (the middle meningeal layer), extend into the dural venous sinuses to drain CSF. These villi act as one-way valves. Meningeal veins, which course through the dura mater, and bridging veins, which drain the underlying neural tissue and puncture the dura mater, empty into these dural sinuses. A rupture of a bridging vein causes a subdural hematoma. The supratentorial dura mater membrane is supplied by small meningeal branches of the trigeminal nerve (
3451613
Brain tumor


of brain cancer is not based upon current phone usage. Human brains are surrounded by a system of connective tissue membranes called meninges that separate the brain from the skull. This three-layered covering is composed of (from the outside in) the dura mater, arachnoid mater, and pia mater. The arachnoid and pia are physically connected and thus often considered as a single layer, the "leptomeninges". Between the arachnoid mater and the pia mater is the subarachnoid space which contains cerebrospinal fluid (CSF). This fluid
16635922
Subdural hematoma


epidural hematomas are usually caused by tears in arteries, resulting in a build-up of blood between the dura mater and the skull. The third type of brain hemorrhage, subarachnoid hemorrhage, causes bleeding into the subarachnoid space between the arachnoid mater and the pia mater. Symptoms of subdural hematomas have a slower onset than those of epidural hematomas because the lower-pressure veins involved bleed more slowly than arteries. Signs and symptoms of acute hematomas may appear in minutes, if not immediately, but can also be delayed as much as
19202504
Pia mater


Pia mater ( or ), often referred to as simply the pia, is the delicate innermost layer of the meninges, the membranes surrounding the brain and spinal cord. "Pia mater" is medieval Latin meaning "tender mother". The other two meningeal membranes are the dura mater and the arachnoid mater. Both the pia and arachnoid mater are derivatives of the neural crest while the dura is derived from embryonic mesoderm. The pia mater is a thin fibrous tissue that is permeable to water and small solutes. The pia mater
8342023
Human brain


start of the midbrain area. The brainstem includes the midbrain, the pons, and the medulla oblongata. Behind the brainstem is the cerebellum (). The cerebrum, brainstem, cerebellum, and spinal cord are covered by three membranes called meninges. The membranes are the tough dura mater; the middle arachnoid mater and the more delicate inner pia mater. Between the arachnoid mater and the pia mater is the subarachnoid space and subarachnoid cisterns, which contain the cerebrospinal fluid. The outermost membrane of the cerebral cortex is the basement membrane
16628443
Ventricular system


protective membranes of the tough dura mater, the arachnoid mater and the pia mater. The cerebrospinal fluid (CSF) within the skull and spine provides further protection and also buoyancy, and is found in the subarachnoid space between the pia mater and the arachnoid mater. The CSF that is produced in the ventricular system is also necessary for chemical stability, and the provision of nutrients needed by the brain. The CSF helps to protect the brain from jolts and knocks to the head and also provides buoyancy and support to the brain against
1629553
Subdural hematoma


hematoma is usually caused by external trauma that creates tension in the wall of a bridging vein as it passes between the arachnoid and dural layers of the brain's lining—i.e., the subdural space. The circumferential arrangement of collagen surrounding the vein makes it susceptible to such tearing. Intracerebral hemorrhage and ruptured cortical vessels (blood vessels on the surface of the brain) can also cause subdural hematoma. In these cases, blood usually accumulates between the two layers of the dura mater. This can cause ischemic brain damage by two
19202509
Lumbar puncture


L4/L5 or L5/S1 and pushed in until there is a "give" as it enters the lumbar cistern wherein the ligamentum flavum is housed. The needle is again pushed until there is a second 'give' that indicates the needle is now past the dura mater. The arachnoid membrane and the dura mater exist in flush contact with one another in the living person's spine due to fluid pressure from CSF in the subarachnoid space pushing the arachnoid membrane out towards the dura. Therefore, once the needle has pierced
21467434
Pia mater


a connection to the anterior fissure. The pia mater attaches to the dura mater through 21 pairs of denticulate ligaments that pass through the arachnoid mater and dura mater of the spinal cord. These denticular ligaments help to anchor the spinal cord and prevent side to side movement, providing stability. The membrane in this area is much thicker than the cranial pia mater, due to the two-layer composition of the pia membrane. The outer layer, which is made up of mostly connective tissue, is responsible for this thickness. Between
8342030
Subdural hematoma


A subdural hematoma (SDH) is a type of hematoma—usually associated with traumatic brain injury—in which blood gathers between the inner layer of the dura mater and the arachnoid mater. It usually results from tears in bridging veins that cross the subdural space. Subdural hematomas may cause an increase in intracranial pressure (ICP), which in turn can cause compression of and damage to delicate brain tissue. Acute subdural hematomas are often life-threatening. Chronic subdural hematomas have a better prognosis if properly managed. In contrast,
19202503
Meningitis


the pia mater. The subarachnoid space separates the arachnoid and pia mater membranes and is filled with cerebrospinal fluid. The outermost membrane, the dura mater, is a thick durable membrane, which is attached to both the arachnoid membrane and the skull. In bacterial meningitis, bacteria reach the meninges by one of two main routes: through the bloodstream or through direct contact between the meninges and either the nasal cavity or the skin. In most cases, meningitis follows invasion of the bloodstream by organisms that live upon mucous surfaces such as
806770
Traumatic brain injury


subdural hematoma, bleeding occurs between the dura and the arachnoid mater. Subarachnoid hemorrhage involves bleeding into the space between the arachnoid membrane and the pia mater. Intraventricular hemorrhage occurs when there is bleeding in the ventricles. Symptoms are dependent on the type of TBI (diffuse or focal) and the part of the brain that is affected. Unconsciousness tends to last longer for people with injuries on the left side of the brain than for those with injuries on the right. Symptoms are also dependent on the injury's severity. With mild
414221
Kay's Tutor v Ayrshire & Arran Health Board


more of the three membranes which envelop the central nervous system consisting of the brain and spinal chord. The three membranes are the dura mater, the arachnoid and the pia mater. Between the arachnoid and the underlying pia mater is the subarachnoid space, which is filled with cerebro-spinal fluid (CSF). The general practitioner had treated the respiratory infection with ampicillin administered orally, but due to vomiting its therapeutic effect may have been to some extent frustrated. On admission to hospital Andrew was found to be seriously ill. He
17170081
Arachnoid mater


plural version, leptomeninges. ("Lepto"- from the Greek root meaning "thin"). Similarly, the dura in this situation is called the pachymeninx. There are two subdivisions of arachnoid mater surrounding the subarachnoid space, the dorsal layer and the ventral layer. The dorsal layer covers internal cerebral veins and fixes them to the surrounding tela choroidea. The ventral layer of arachnoid membrane, on the other hand, is a direct anterior extension of this arachnoid envelope that the dorsal layer forms over the pineal region. CSF circulates in
889367
Laminar organization


to form endoderm, and a third layer of cells known as mesoderm. Cells that remain in the epiblast become ectoderm. This is the trilaminar disc and the epiblast cells have given rise to the three germ layers. In the brain a laminar organization is evident in the arrangement of the three meninges, the membranes that cover the brain and spinal cord. These membranes are the dura mater, arachnoid mater, and pia mater. The dura mater has two layers a periosteal layer near to the bone of the skull, and a
20306367
Meninges


an internal leaflet: the secondary meninx, and into an external one: the dura mater. Finally, in higher vertebrates, even the secondary meninx divides into the arachnoid and the pia. In the same animals, Sterzi demonstrated that, while in the spinal medulla the dura keeps its identity, in the skull it fuses with the periosteum. He also demonstrated the continuity of all meninges with the envelopes of nerves and with the filum terminale. Mammals (as higher vertebrates) retain the dura mater, and the secondary meninx divides
14808696
Arachnoid mater


the subarachnoid space (between arachnoid and pia mater). Cerebrospinal fluid is produced by the choroid plexus (inside the ventricles of the brain, which are in direct communication with the subarachnoid space so the CSF can flow freely through the nervous system). Cerebrospinal fluid is a transparent, colourless fluid and it is produced at about 500 ml/day. Its electrolyte levels, glucose levels, and pH are very similar to those in plasma, but the presence of blood in cerebrospinal fluid is always abnormal. The arachnoid mater is
889368
Epidural space


In the spine, the epidural space (from Ancient Greek ἐπί, "on, upon" + dura mater also known as "epidural cavity", "extradural space" or "peridural space") is an anatomic space that is the outermost part of the spinal canal. It is the space within the canal (formed by the surrounding vertebrae) lying outside the dura mater (which encloses the arachnoid mater, subarachnoid space, the cerebrospinal fluid, and the spinal cord). In humans the epidural space contains lymphatics,
14193757
Denticulate ligaments


The denticulate ligaments are triangular shaped ligaments that anchor the spinal cord along its length, at each side, to the dura mater. The bases of the ligaments arise in the pia mater and they are firmly attached to the arachnoid mater and dura mater at the apex. They have 21 attachments per side. Named for their tooth-like appearance, the denticulate ligaments are traditionally believed to provide stability for the spinal cord against motion within the vertebral column. From a clinical standpoint, denticulate ligaments do not play a significant role in
9026431
Vein


and exits the fascia only near the knee. Incompetence of this vein is an important cause of varicose veins of lower limbs. The Thebesian veins within the myocardium of the heart are valveless veins that drain directly into the chambers of the heart. The coronary veins all empty into the coronary sinus which empties into the right atrium. The dural venous sinuses within the dura mater surrounding the brain receive blood from the brain and also are a point of entry of cerebrospinal fluid from arachnoid villi absorption. Blood eventually enters the internal jugular vein
8569234
Pathology of multiple sclerosis


inflammation. A relationship between neural damage and N-Acetyl-Aspartate concentration has been established, and this could lead to new methods for early MS diagnostic through magnetic resonance spectroscopy Axonal degeneration at CNS can be estimated by N-acetylaspartate to creatine (NAA/Cr) ratio, both measured by with proton magnetic resonance spectroscopy. The meninges are three layers that protect the brain and the spinal cord. They are called (from the outside to the inside) the dura mater, the arachnoid mater and the pia mater. The
3581447
Arachnoiditis


or because of efferent neurological or other motor symptoms, such as difficulties controlling limbs. Difficulty sitting can be problematic for patients who have trouble standing or walking for long periods, as wheelchairs are not always helpful in such cases. The root cause of the condition is not entirely clear, and it appears to have multiple causes, including iatrogenic cause from misplaced epidural steroid injection therapy when accidentally administered intrathecally (inside the dura mater, the sac enveloping the arachnoid mater), or from contrast media used in myelography prior to the introduction
18136287
Neuromere


it contains a network of blood vessels. The arachnoid mater is the middle protective layer. Its name comes from the fact that the tissue has a spiderweb-like appearance. The space between the arachnoid and the underlying pia mater is called the subarachnoid space. The subarachnoid space contains cerebrospinal fluid (CSF). The medical procedure known as a lumbar puncture (or "spinal tap") involves use of a needle to withdraw cerebrospinal fluid from the subarachnoid space, usually from the lumbar region of the spine. The pia mater
20485644
Lumbar puncture


the dura mater it has also traversed the thinner arachnoid membrane. The needle is then in the subarachnoid space. The stylet from the spinal needle is then withdrawn and drops of cerebrospinal fluid are collected. The opening pressure of the cerebrospinal fluid may be taken during this collection by using a simple column manometer. The procedure is ended by withdrawing the needle while placing pressure on the puncture site. The spinal level is so selected to avoid spinal injuries. In the past, the patient would lie on their back for at least six
21467435
Subdural hematoma


medications can have a subdural hematoma after a relatively minor traumatic event. Another cause can be a reduction in cerebrospinal fluid pressure, which can reduce pressure in the subarachnoid space, pulling the arachnoid away from the dura mater and leading to a rupture of the blood vessels. Factors increasing the risk of a subdural hematoma include very young or very old age. As the brain shrinks with age, the subdural space enlarges and the veins that traverse the space must cover a wider distance, making them more vulnerable to tears. The elderly
19202507
Meningioma


as meningiomas were referred to with a wide range of names in older medical literature, depending on the source. Various descriptors included "fungoid tumors", "fungus of the dura mater", "epithelioma", "psammoma", "dural sarcoma", "dural endothelioma", "fibrosarcoma", "angioendothelioma", "arachnoidal fibroboastoma", "endotheliosis of the meninges", "meningeal fibroblastoma", "meningoblastoma", "mestothelioma of the meninges", "sarcoma of the dura", and others
16673408
Cranial cavity


nervous system developed, which are the pia mater, the arachnoid mater, and the dura mater. The latter is the thickest and outermost of the three membrane layers; it contains the most collagen, and it is derived from the mesoderm - the middle germ layer or the primary layer of the cells formed in embryogenic development via epiginetic effects induced by developmental cues, in the early embryo. Also there are the two parietal bones and the two temporal bones, which are a part of the dorsal cavity located on the posterior of
8895828
Longitudinal fissure


following stages, a nerve tube appears and is folded into a hollow structure, as shown in . The bilateral sides of this structure then give rise to the two hemispheres of the Homo sapiens cortex, but do not merge at any point besides the corpus callosum. As a result, the longitudinal fissure is formed. All three meninges of the cortex (dura mater, arachnoid mater, pia mater) fold and descend deep down into the longitudinal fissure, physically separating the two hemispheres. Falx cerebri is the name given to the
12857192
Paleoneurobiology


-of-Paris while sitting in a water bath to equalize forces and retain the original shape. Natural endocasts are very rare; most of those that are studied are the result of artificial methods. Although the name implies that it is a copy of the once living brain, endocasts rarely exhibit convolutions due to buffering by the pia mater, arachnoid mater, and dura mater that once surrounded and protected the brain tissue. Furthermore, not all endocasts are created from a complete cranial fossil and subsequently, the missing parts are approximated
4804298
Giuseppe Sterzi


internal leaflet: the secondary meninx, and into an external one: the dura mater. Finally, in higher vertebrates, even the secondary meninx divides into the arachnoid and the pia. In the same animals, Sterzi demonstrated that, while in the spinal medulla the dura keeps its identity, in the skull it fuses with the periosteum (Sterzi,1902). He also demonstrated the continuity of all meninges with the envelopes of nerves and with the filum terminale. The second group of studies, “Vessels of the Spinal Medulla” (
18631783
Oculomotor nerve


the arachnoid. It passes between the superior cerebellar (below) and posterior cerebral arteries (above), and then pierces the dura mater anterior and lateral to the posterior clinoid process, passing between the free and attached borders of the tentorium cerebelli. It traverses the cavernous sinus, above the other orbital nerves receiving in its course one or two filaments from the cavernous plexus of the sympathetic nervous system, and a communicating branch from the ophthalmic division of the trigeminal nerve. As the oculomotor nerve enters the orbit it divides into a
11481282
Electrocorticography


and thus must be conducted through several layers of the cerebral cortex, cerebrospinal fluid (CSF), pia mater, and arachnoid mater before reaching subdural recording electrodes placed just below the dura mater (outer cranial membrane). However, to reach the scalp electrodes of a conventional electroencephalogram (EEG), electrical signals must also be conducted through the skull, where potentials rapidly attenuate due to the low conductivity of bone. For this reason, the spatial resolution of ECoG is much higher than EEG, a critical imaging advantage for presurgical
21110389
Dura mater


artery and some accessory arteries are responsible for blood supply, the middle meningeal artery is a direct branch from the maxillary artery and enter the cranial cavity through the foramen spinosum and then divides into anterior (which runs usually in vertical direction across the pterion) and posterior (which runs posteriosuperiorly) branches, while the accessory meningeal arteries (which are branches from the maxillary artery) enter the skull through foramen ovale and supply area between the two foramina, and the in posterior cranial fossa the dura mater has numerous blood supply from different
3451611
Complications of traumatic brain injury


such as meningitis. Pneumocephalus occurs when air enters the intracranial cavity and becomes trapped in the subarachnoid space. Infections within the intracranial cavity are a dangerous complication of TBI. They may occur outside of the dura mater, below the dura, below the arachnoid (meningitis), or within the brain itself (abscess). Most of these injuries develop within a few weeks of the initial trauma and result from skull fractures or penetrating injuries. Standard treatment involves antibiotics and sometimes surgery to remove the infected tissue. Injuries to the base
2524551
Spontaneous cerebrospinal fluid leak


, leading to CSF leak and intracranial hypotension. Patients with a "nude nerve root", where the root sleeve is absent, are at increased risk for developing recurrent CSF leaks. Lumbar disc herniation has been reported to cause CSF leaks in at least one case. Degenerative spinal disc diseases cause a disc to pierce the dura mater, leading to a CSF leak. Cerebrospinal fluid is produced by the choroid plexus in the ventricles of the brain and contained by the dura and arachnoid layers of the meninges. The brain floats in
9360542
Spinal cavity


The spinal cavity (or vertebral cavity or spinal canal) is the cavity that contains the spinal cord within the vertebral column, formed by the vertebrae through which the spinal cord passes. It is a process of the dorsal body cavity. This canal is enclosed within the vertebral foramen of the vertebrae. In the intervertebral spaces, the canal is protected by the ligamentum flavum posteriorly and the posterior longitudinal ligament anteriorly. The outermost layer of the meninges, the dura mater, is closely associated with the arachnoid mater which in turn is
9384200
Subarachnoid cisterns


The subarachnoid cisterns are spaces formed by openings in the subarachnoid space, an anatomic space in the meninges of the brain. The space separates two of the meninges, the arachnoid mater and the pia mater. These cisterns are filled with cerebrospinal fluid. Although the pia mater adheres to the surface of the brain, closely following the contours of its gyri and sulci, the arachnoid mater only covers its superficial surface, bridging across the gyri. This leaves wider spaces between the pia and arachnoid and the cavities are known as the subarachnoid
20303196
Superior sagittal sinus


on either side of the sinus: a small frontal, a large parietal, and an occipital, intermediate in size between the other two. Most of the cerebral veins from the outer surface of the hemisphere open into these lacunæ, and numerous arachnoid granulations (Pacchionian bodies) project into them from below. The superior sagittal sinus receives the superior cerebral veins, veins from the diploë and dura mater, and, near the posterior extremity of the sagittal suture, veins from the pericranium, which pass through the parietal foramina. Cerebrospinal
4868491
Dura mater


mater. It surrounds and supports the dural sinuses (also called dural venous sinuses, cerebral sinuses, or cranial sinuses) and carries blood from the brain toward the heart. The dura mater has two layers called "lamellae": The superficial layer (also called the periosteal layer), which serves as the skull's inner periosteum, called the endocranium; and a deep layer called the meningeal layer; the actual dura mater. When it covers the spinal cord it is known as the "dural sac" or thecal sac
3451609
Leptomeningeal collateral circulation


The leptomeningeal collateral circulation (also known as leptomeningeal anastomoses or pial collaterals) is a network of small blood vessels in the brain that connects branches of the middle, anterior and posterior cerebral arteries (MCA, ACA, and PCA). Leptomeningeal collaterals lie within the leptomeninges, the two deep layers of the meninges called the pia mater and the arachnoid mater. Their diameter has been measured at approximately 300 micrometers, but there is variability between individuals in the size, quantity and location of these vessels, and between either hemisphere within
18510913
Dura mater


to this anatomical relationship such as headaches, trigeminal neuralgia and other symptoms that involved the cervical dura. The rectus capitis posterior minor has a similar attachment. The dura-muscular, dura-ligamentous connections in the upper cervical spine and occipital areas may provide anatomic and physiologic answers to the cause of the cervicogenic headache. This proposal would further explain manipulation's efficacy in the treatment of cervicogenic headache. The American Red Cross and some other agencies accepting blood donations consider dura mater transplants, along with receipt of pituitary-derived growth hormone
3451616
Dura mater


possible arteries: A. posterior meningeal artery (from the ascending pharyngeal artery through the jugular foramen) B. meningeal arteries (from the ascending pharyngeal artery through hypoglossal canal) C. meningeal arteries (from occipital artery through jugular or mastoid foramen) D. meningeal arteries (from vertebral artery through foramen magnum) The two layers of dura mater run together throughout most of the skull. Where they separate, the gap between them is called a dural venous sinus. These sinuses drain blood and cerebrospinal fluid (CSF) from the brain and empty into
3451612
Cerebrospinal fluid


cerebral blood flow. CSF occupies the subarachnoid space (between the arachnoid mater and the pia mater) and the ventricular system around and inside the brain and spinal cord. It fills the ventricles of the brain, cisterns, and sulci, as well as the central canal of the spinal cord. There is also a connection from the subarachnoid space to the bony labyrinth of the inner ear via the perilymphatic duct where the perilymph is continuous with the cerebrospinal fluid. A sample of CSF can be taken via lumbar puncture. This can
7878716
Spinal root of accessory nerve


foramen, through which it passes, lying in the same sheath of dura mater as the vagus, but separated from it by a fold of the arachnoid. In the jugular foramen, it receives one or two filaments from the cranial part of the nerve, or else joins it for a short distance and then separates from it again. As it exits from the jugular foramen, it runs backward in front of the internal jugular vein in 66.6% of cases, and behind it in 33% of cases. The nerve then
961309
Cranial drill


it might be necessary to drill a hole in the skull to be able to access the dura mater or the brain itself, and to relieve brain pressure or blood clots. With the use of modern types of cranial drills, surgeons are able to create holes in the bone structure without traumatizing underlying brain tissue. The drill's working tool tip consists of a spiral blade that is framed by a guard device with an angled cranium guide that rests against the inner layer of the skull bone. The dura guard pushes the dura mater
8054940
Traumatic brain injury


among tissue. In contrast, intracranial hemorrhage involves bleeding that is not mixed with tissue. Hematomas, also focal lesions, are collections of blood in or around the brain that can result from hemorrhage. Intracerebral hemorrhage, with bleeding in the brain tissue itself, is an intra-axial lesion. Extra-axial lesions include epidural hematoma, subdural hematoma, subarachnoid hemorrhage, and intraventricular hemorrhage. Epidural hematoma involves bleeding into the area between the skull and the dura mater, the outermost of the three membranes surrounding the brain. In
414220
Cerebrospinal fluid


system by entering the dural venous sinuses via arachnoid granulations. These are outpouchings of the arachnoid mater into the venous sinuses around the brain, with valves to ensure one-way drainage. This occurs because of a pressure difference between the arachnoid mater and venous sinuses. CSF has also been seen to drain into lymphatic vessels, particularly those surrounding the nose via drainage along the olfactory nerve through the cribriform plate. The pathway and extent are currently not known, but may involve CSF flow along some cranial nerves and be more prominent in
7878732
Optic nerve


the other eleven cranial nerves and considered to be part of the peripheral nervous system. The optic nerve is ensheathed in all three meningeal layers (dura, arachnoid, and pia mater) rather than the epineurium, perineurium, and endoneurium found in peripheral nerves. Fiber tracts of the mammalian central nervous system (as opposed to the peripheral nervous system) are incapable of regeneration, and, hence, optic nerve damage produces irreversible blindness. The fibers from the retina run along the optic nerve to nine primary visual nuclei in the brain
19187989
Sports-related traumatic brain injury


basketball, motor cycling, scuba diving, mountaineering, hang gliding, skydiving, and horseback riding. Council on scientific affairs. Following a serve brain injury or a skull fracture one of the two hematomas may occur. An extradural hematoma is a TBI where blood collects between the inside of the skull and the dura, the thick outer covering of the brain. A subdural hematoma is a localized collection of blood under the surface of the dura matter. Blood collects on the outermost layer of the brain and creates an intracranial pressure.
15717268
Pia mater


The CSF travels from the ventricles and cerebellum through three foramina in the brain, emptying into the cerebrum, and ending its cycle in the venous blood via structures like the arachnoid granulations. The pia spans every surface crevice of the brain other than the foramina to allow the circulation of CSF to continue. Pia mater allows for the formation of perivascular spaces that help serve as the brain’s lymphatic system. Blood vessels that penetrate the brain first pass across the surface and then go inwards toward the brain. This direction of flow leads
8342034
Meninges


system. This thin, transparent membrane is composed of fibrous tissue and, like the pia mater, is covered by flat cells also thought to be impermeable to fluid. The shape of the arachnoid does not follow the convolutions of the surface of the brain and so looks like a loosely fitting sac. In particular, in the region of the brain a large number of fine filaments called arachnoid trabeculae pass from the arachnoid through the subarachnoid space to blend with the tissue of the pia mater. The arachnoid is composed of an outermost
14808689
Middle meningeal artery


that spread out between the dura mater and internal surface of the cranium, some passing upward as far as the vertex, and others backward to the occipital region. The "posterior branch" curves backward on the squamous part of the temporal bone, and, reaching the parietal bone some distance in front of its mastoid angle, divides into branches that supply the posterior part of the dura mater and cranium. The branches of the middle meningeal artery are distributed partly to the dura mater, but chiefly to the bones; they anastomose
16148417
Meninges


the leptomeninges along the surface of the brain. Because the arachnoid is connected to the pia by cob-web like strands, it is structurally continuous with the pia, hence the name pia-arachnoid or leptomeninges. They are responsible for the production of beta-trace protein (prostaglandin D2 synthase), a major cerebrospinal fluid protein. The subarachnoid space is the space that normally exists between the arachnoid and the pia mater, which is filled with cerebrospinal fluid, and continues down the spinal cord. Spaces are formed from openings
14808692
Pia mater


surface of the brain and loosely connects to the arachnoid layer. Because of this continuum, the layers are often referred to as the pia arachnoid or leptomeninges. A subarachnoid space exists between the arachnoid layer and the pia, into which the choroid plexus releases and maintains the cerebrospinal fluid (CSF). The subarachnoid space contains trabeculae, or fibrous filaments, that connect and bring stability to the two layers, allowing for the appropriate protection from and movement of the proteins, electrolytes, ions, and glucose contained within the CSF.
8342025
Cisterna magna


The cisterna magna (or cerebellomedullaris cistern) is one of three principal openings in the subarachnoid space between the arachnoid and pia mater layers of the meninges surrounding the brain. The openings are collectively referred to as the subarachnoid cisterns. The cisterna magna is located between the cerebellum and the dorsal surface of the medulla oblongata. Cerebrospinal fluid produced in the fourth ventricle drains into the cisterna magna via the lateral apertures and median aperture. The two other principal cisterns are the "pontine cistern" located between the pons and the medulla and the
20303209
Meninges


cord, following all of the brain's contours (the gyri and sulci). It is a very thin membrane composed of fibrous tissue covered on its outer surface by a sheet of flat cells thought to be impermeable to fluid. The pia mater is pierced by blood vessels to the brain and spinal cord, and its capillaries nourish the brain. The arachnoid and pia mater together are sometimes called the "leptomeninges", literally "thin meninges" ( leptos - thin). Acute meningococcal meningitis can lead to an exudate within
14808691
Intracranial hemorrhage


deficits depending on the site of hematoma and brain injury, increased intracranial pressure leading to herniation of brain and ischemia due to reduced blood supply and seizures. A "subarachnoid hemorrhage" is bleeding into the subarachnoid space—the area between the arachnoid membrane and the pia mater surrounding the brain. Besides from head injury, it may occur spontaneously, usually from a ruptured cerebral aneurysm. Symptoms of SAH include a severe headache with a rapid onset (thunderclap headache), vomiting, confusion or a lowered level of consciousness, and sometimes
12300692
Arachnoid cyst


space). Blood vessels on the surface of a cyst may tear and bleed into the cyst (intracystic hemorrhage), increasing its size. If a blood vessel bleeds on the outside of a cyst, a collection of blood (hematoma) may result. In the cases of intracystic hemorrhage and hematoma, the individual may have symptoms of increased pressure within the cranium and signs of compression of nearby nerve (neural) tissue. Some scientists debate whether arachnoid cysts are a true congenite condition or if this should be separated from secondary
782112
Human brain


a small posterior communicating artery to join with the internal carotid arteries. Cerebral veins drain deoxygenated blood from the brain. The brain has two main networks of veins: an exterior or superficial network, on the surface of the cerebrum that has three branches, and an interior network. These two networks communicate via anastomosing (joining) veins. The veins of the brain drain into larger cavities the dural venous sinuses usually situated between the dura mater and the covering of the skull. Blood from the cerebellum and midbrain drains into the great
16628466
Dura mater


of trigeminal neuralgia via a microvascular decompression require that an incision is made to the dura mater. To achieve a watertight repair and avoid potential post-operative complications the dura is typically closed with sutures. In the event that there is a dural deficiency, a dural substitute may be used to replace this membrane. Small gaps in the dura can be covered with a surgical sealant film. In 2011, researchers discovered a connective tissue bridge from the rectus capitis posterior major to the cervical dura mater. Various clinical manifestations may be linked
3451615
Pia mater


the two layers are spaces which exchange information with the subarachnoid cavity as well as blood vessels. At the point where the pia mater reaches the conus medullaris or medullary cone at the end of the spinal cord, the membrane extends as a thin filament called the filum terminale or terminal filum, contained within the lumbar cistern. This filament eventually blends with the dura mater and extends as far as the coccyx, or tailbone. It then fuses with the periosteum, a membrane found at the surface of all bones, and forms the
8342031
Arachnoiditis


Arachnoiditis is an inflammatory condition of the arachnoid mater or 'arachnoid', one of the membranes known as meninges that surround and protect the nerves of the central nervous system, including the brain and spinal cord. The arachnoid can become inflamed because of adverse reactions to chemicals, infection from bacteria or viruses, as the result of direct injury to the spine, chronic compression of spinal nerves, complications from spinal surgery or other invasive spinal procedures, or the accidental intrathecal injection of steroids intended for the epidural space. Inflammation can sometimes
18136284
Longitudinal fissure


dura mater in-between the two hemispheres, whose significance rises from the fact that it is the outermost layer of the meninges. These layers prevent any direct connectivity between the bilateral lobes of the cortex, thus requiring any tracts to pass through the corpus callosum. The vasculature of falx cerebri supplies blood to the innermost surfaces of the cortex, neighboring the midsagittal plane. The two hemispheres of the human cortex are not perfectly symmetrical, both in structure and in function. For example, the planum temporale, roughly corresponding to the
12857193
Neuromere


from and motor output goes to the arms. The lumbar enlargement, located between L1 and S3 spinal segments, handles sensory input and motor output coming from and going to the legs. The spinal cord is protected by three layers of tissue, called spinal meninges, that surround the canal. The dura mater is the outermost layer, and it forms a tough protective coating. Between the dura mater and the surrounding bone of the vertebrae is a space called the epidural space. The epidural space is filled with adipose tissue, and
20485643
Epidural blood patch


An epidural blood patch is a surgical procedure that uses autologous blood in order to close one or many holes in the dura mater of the spinal cord, usually as a result of a previous lumbar puncture. The procedure can be used to relieve post dural puncture headaches caused by lumbar puncture (spinal tap). A small amount of the patient's blood is injected into the epidural space near the site of the original puncture; the resulting blood clot then "patches" the meningeal leak. The procedure carries the typical risks of
9269615
Dura mater


. The dura separates into two layers at "dural reflections" (also known as "dural folds"), places where the inner dural layer is reflected as sheet-like protrusions into the cranial cavity. There are two main dural reflections: Two other dural infoldings are the cerebellar falx and the sellar diaphragm: This depends upon the area of the cranial cavity: in the anterior cranial fossa the anterior meningeal artery (branch from the ethmoidal artery) is responsible for blood supply, in the middle cranial fossa the middle meningeal
3451610
Brain herniation


downwards transtentorial herniation. In "cingulate" or "subfalcine herniation", the most common type, the innermost part of the frontal lobe is scraped under part of the falx cerebri, the dura mater at the top of the head between the two hemispheres of the brain. Cingulate herniation can be caused when one hemisphere swells and pushes the cingulate gyrus by the falx cerebri. This does not put as much pressure on the brainstem as the other types of herniation, but it may interfere with blood vessels in the frontal lobes that
13255274
Stroke


, such as cocaine and methamphetamine are at a high risk for ischemic strokes. There are two main types of hemorrhagic stroke: The above two main types of hemorrhagic stroke are also two different forms of intracranial hemorrhage, which is the accumulation of blood anywhere within the cranial vault; but the other forms of intracranial hemorrhage, such as epidural hematoma (bleeding between the skull and the dura mater, which is the thick "outermost" layer of the meninges that surround the brain) and subdural hematoma (bleeding in the subdural space
868689
Internal carotid artery


by the medial and inferior periosteum of the anterior clinoid process. The cavernous segment is surrounded by the cavernous sinus. In this part of its course, the artery is situated between the layers of the dura mater forming the cavernous sinus, but covered by the lining membrane of the sinus. It at first ascends toward the posterior clinoid process, then passes forward by the side of the body of the sphenoid bone, again curves upward on the medial side of the anterior clinoid process, and perforates the dura mater forming the roof
1733958
Subarcuate fossa


In the temporal bone at the sides of the skull, above and between the aquæductus vestibuli is an irregular depression which lodges a process of the dura mater and transmits a small vein and the subarcuate artery a branch of the meatal segment of anterior inferior cerebellar artery, which is an end artery that supplies blood to the inner ear; in the infant this depression is represented by a large fossa, the subarcuate fossa, which extends backward as a blind tunnel under the superior semicircular canal. It is extensive in most primates (except
4555216
Trigonocephaly


is moved 2 cm. forward and fixed only to the frontal process of the zygoma without fixation to the cranium. Lastly, the frontal bone is divided into two, rotated and attached to the supraorbital bar causing a nude area (craniectomy) between the parietal bone and frontal bone. Bone will eventually regenerate since the dura mater lies underneath (the dura mater has osteogenic capabilities). This results in an advancement and straightening of the forehead. The so-called 'floating forehead technique' combined with the remodelling of the supraorbital
8096069
Epidural abscess


An epidural abscess refers to a collection of pus and infectious material located in the epidural space of the central nervous system. Due to its location adjacent to brain or spinal cord, epidural abscesses have the potential to cause weakness, pain, and paralysis. Spinal epidural abscess (SEA) is a collection of pus or inflammatory granulation between the dura mater and the vertebral column. Currently the annual incidence rate of SEAs is estimated to be 2.5-3 per 10,000 hospital admissions. Incidence of SEA is on the rise, due to
4122690
Spinal cord injury research


Chemical stimulation of the spinal cord is administered through the microfluidic channel of the e-dura. The e-dura implants, unlike previous surface implants, closely mimic the physical properties of living tissue and can deliver electric impulses and pharmacological substances simultaneously. Artificial dura mater was constructed through the utilization of PDMS and gelatin hydrogel. The hydrogel simulates spinal tissue and a silicone membrane simulates the dura mater. These properties allow the e-dura implants to sustain long-term application to the spinal cord and brain without leading to inflammation,
8367052
List of English words of Arabic origin (T-Z)


or not. See List of English words of Semitic origin, excluding words known to be of Hebrew or Arabic origin. The list has been restricted to loan words: It excludes loan translations. Here's an example of a loan translation. In Arabic the words for father, mother and son are often used to denote relationships between things. Surrounding the brain and spinal chord is a tough outer layer of membrane called in today's English the dura mater. The words "dura" = "hard" and "mater"
140439
Mesoderm


mesodermal components of the limbs. Some of the mesoderm derivatives include the muscle (smooth, cardiac and skeletal), the muscles of the tongue (occipital somites), the pharyngeal arches muscle (muscles of mastication, muscles of facial expressions), connective tissue, dermis and subcutaneous layer of the skin, bone and cartilage, dura mater, endothelium of blood vessels, red blood cells, white blood cells, and microglia, the kidneys and the adrenal cortex. During the third week a process called gastrulation creates a mesodermal layer
17993264
Ramón Carrillo


papillitis; described in detail the cerebral scleroses, during whose research he performed many cerebral transplants (brain grafts) between living rabbits; and histologically reclassified the cerebral tumors and the inflammations of the innermost brain envelope (arachnoid mater) known as arachnoiditis. He also proposed a widely used, pre-DSM classification of mental illnesses. Against considerable opposition from conservative colleagues, in 1942 and at the age of 36 Carrillo became the Chair of Neurosurgery at the University of Buenos Aires School of Medicine. Among the influential Argentine physicians he trained
21949419
Diastematomyelia


is not accompanied by any bony spur or fibrous band and is rarely symptomatic unless hydromyelia or tethering is present. The other 40% of patients have a bony spur or a fibrous band that passes through the two hemicords. In these cases, the dura and arachnoid are split into two separate dural and arachnoidal sacs, each surrounding the corresponding hemicord which are not necessarily symmetric. Each hemicord contains a central canal, one dorsal horn (giving rise to a dorsal nerve root), and one ventral horn (giving rise to a
16609372
Failed back syndrome


In an extensive laminectomy involving 2 or more vertebra, post operative scarring is the norm. It is most often seen around the L5 and S1 nerve roots. Fibrous scarring can also be a complication within the subarachnoid space. It is notoriously difficult to detect and evaluate. Prior to the development of magnetic resonance imaging, the only way to ascertain the presence of arachnoiditis was by opening the dura. In the days of CT scanning and Pantopaque and later, Metrizamide myelography, the presence of arachnoiditis could be speculated based on radiographic findings
7971841
Zhang Haidi


Shandong Province. She became a paraplegic at age five. Due to pathological conditions in her blood vessels near the dura mater of her spine, she underwent six major operations to have six of her spinal plates removed between 1960 and 1976. As a result, she became paralyzed in her lower body. Unable to attend school because of her disability, she taught herself to university level. She learned multiple foreign languages, including English, Japanese, German, and Esperanto, and became a translator and writer. In 1993, Jilin
1580450
Pituitary adenoma


of the body's endocrine functions via the secretion of various hormones into the circulatory system. The pituitary gland is located below the brain in a depression (fossa) of the sphenoid bone known as the sella turcica. Although anatomically and functionally connected to the brain, the pituitary gland sits outside the blood–brain barrier. It is separated from the subarachnoid space by the diaphragma sella, therefore the arachnoid mater and thus cerebral spinal fluid cannot enter the sella turcica. The pituitary gland is divided into two lobes, the anterior
12747849
Dural venous sinuses


they lack a full set of vessel layers (e.g. tunica media) characteristic of arteries and veins. It also lacks valves (in veins; with exception of materno-fetal blood circulation i.e. placental artery and pulmonary arteries both of which carry deoxygenated blood). The sinuses can be injured by trauma in which damage to the dura mater, may result in blood clot formation (thrombosis) within the dural sinuses. Other common causes of dural sinus thrombosis include tracking of infection through the ophthalmic vein in orbital cellulitis. While rare,
3085668
Barrier membrane


skin and freeze-dried dura mater. Recently developed synthetic membranes often combine different materials. Collagen membranes are of either type I or II collagen from cows or pigs. They are often cross-linked and take between four and forty weeks to resorb, depending on the type. Collagen absorbable barrier membranes do not require surgical removal, inhibit migration of epithelial cells, promote the attachment of new connective tissue, are not strongly antigenic and prevent blood loss by promoting platelet aggregation leading to early clot formation and wound stabilization. Collagen membranes
15994716
Criticism of evolutionary psychology


young children, there are other organs in many other species that consume more calories than their human counterparts. This means that humans do not stand out in requirements for calories at any stage of life, though human brains stand out in requiring higher amounts of many different essential nutrients while other organs in other species may require higher amounts of two or three specific micronutrients. While studies of blood flow in the brain's dura mater in fossil humans show a negligible difference in oxygen and with it caloric requirements between Neanderthals and modern humans,
18325120
Pia mater


from the delicate strands of connective tissue called the arachnoid trabeculae. In the perivascular spaces, the pia mater begins as mesothelial lining on the outer surface, but the cells then fade to be replaced by neuroglia elements. Although the pia mater is primarily structurally similar throughout, it spans both the spinal cord’s neural tissue and runs down the fissures of the cerebral cortex in the brain. It is often broken down into two categories, the cranial pia mater (pia mater encephali) and the spinal pia mater (pia mater spinalis
8342027
Sphenoid wing meningioma


A sphenoid wing meningioma is a benign brain tumor near the sphenoid bone. A meningioma is a benign brain tumor. It originates from the arachnoid (not the dura), the tissue covering the brain and spinal cord lying deep to the dura. Meningiomas are much more common in females, and are more common after 50 years of age. Of all cranial meningiomas, about 20% of them are in the sphenoid wing. In some cases, deletions involving chromosome 22 are involved. Sphenoid wing meningiomas are diagnosed by the combination
22217190
Microvascular decompression


symptomatic side facing up. Electrical monitoring of facial function and hearing is used. A straight incision is made two finger-breadths behind the ear about the length of the ear. A portion of the skull around 30 mm (1.2 inches) in diameter is removed exposing the underlying brain covering known as the dura. The dura is opened to expose the cerebellum. The cerebellum is allowed to fall out of the way exposing the side of the brainstem. Using a microscope and micro-instruments, the arachnoid membrane is dissected allowing
568520