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- uncal: Anatomy. relating to the uncus. The uncus, is separated from the apex of the temporal lobe by a slight fissure. Two significant clinical aspects of the uncus:
Seizures, often preceded by hallucinations of disagreeable odors, often originate in the uncus.
In situations of tumor, hemorrhage, or edema, increased pressure within the cranial cavity, especially if the mass is in the middle fossa, can push the uncus over the tentorial notch against the brainstem and its corresponding cranial nerves. If the uncus becomes herniated the structure lying just medial to it, cranial nerve III, can become compressed. This causes problems associated with a non-functional or problematic CN III - the pupil on the ipsilateral side fails to constrict to light and absence of medial/superior movement of the orbit, resulting in a fixed, dilated pupil and an eye with a characteristic "down and out" position due to dominance of the abducens and trochlear nerves. Further pressure on the midbrain results in progressive lethargy, coma and death due to compression of the mesencephalic reticular activating system.
- undifferentiated: (adjective)
: not differentiated
- unilateral: Occurring on, performed on, or affecting one side of the body or one of its part.
- v p shunt: Ventriculoperitoneal shunting is surgery to relieve increased pressure inside the skull due to excess cerebrospinal fluid (CSF) on the brain (hydrocephalus). Placement of a VP-shunt is performed by a neurosurgeon.
- V.P. Shunt: Ventriculoperitoneal Shunt. A surgically implanted passage, often a tube, by cerebrospinal fluid (as blood) is diverted from between a ventricle of the brain and the peritoneal cavity to another area of the body.
- vaccine: matter or a preparation containing the virus of cowpox in a form used for vaccination
2 : a preparation of killed microorganisms, living attenuated organisms, or living fully virulent organisms that is administered to produce or artificially increase immunity to a particular disease ; also : a mixture of several such vaccines
- vagus: See: 10th cranial nerve.
- Vagus Nerve: See: 10th Cranial Nerve
- vallecula: An anatomical groove, channel, or depression, such as on the underside of the cerebellum separating the hemispheres and including the inferior vermis.
- VAS: Visual Analogue Scale, a scale in which a patient marks a point on a line between two points to indicate how much of a certain symptom, such as pain, he or she feels.
- vascular malformation: Defect, ventricular septal (VSD): A hole in the septum (the wall) between the lower chambers of the heart (the ventricles).
Ventricular Septal Defect is the most common type of heart malformation (congenital heart disease). At least 1 baby in every 500 is born with a VSD.
A VSD lets blood from the left ventricle (where it is under relatively high pressure) shunt into the right ventricle which has to do extra work to handle the additional blood, may have trouble keeping up with the load, enlarge, and fail. The lungs receive too much blood under too great pressure, the arterioles (small arteries) in the lungs thicken up in response, and permanent vascular damage can be done to the lungs.
Small VSDs (less than 0.5 square cm in area) permit only minimal shunting of blood and the pressure in the right ventricle remains normal and the heart (and lungs) function normally. Surgical repair is not recommended for small VSDs.
No matter what size a VSD is, it carries an increased risk for infection of the heart walls and valves (endocarditis). To prevent endocarditis, anyone with a VSD should take antibiotics before dental and other particular procedures.
With a large VSD (usually one greater than 1.0 square cm in area), there is a significant shunt into the right ventricle, excessive blood flow into the lungs, and pulmonary hypertension. The child may have labored breathing, difficulty feeding, and grow poorly. Medically, the heart that has a large VSD should be kept strong. Vascular disease in the lungs must not be allowed to develop. Surgery should be done to close a large VSD.
The prognosis (outlook) with VSD is generally excellent.
- vasculature: The disposition or arrangement of blood vessels in an organ or part.
- vasculitis: Inflammation of a blood or lymph vessel.
- vasogenic: See Vasogenic Edema
- vasogenic edema: Vasogenic Cerebral Edema occurs due to a breakdown of tight endothelial junctions which make up the blood-brain barrier (BBB). This allows normally excluded intravascular proteins and fluid to penetrate into cerebral parenchymal extracellular space. Once plasma constituents cross the BBB, the edema spreads; this may be quite fast and widespread. As water enters white matter it moves extracellularly along fiber tracts and can also affect the gray matter. This type of edema is seen in response to trauma, tumors, focal inflammation, late stages of cerebral ischemia and hypertensive encephalopathy.
- vasospasm: Sharp and often persistent contraction of a blood vessel reducing its caliber and blood flow.
- VElum: a membrane or membranous part resembling a veil or curtain: as a : SOFT PALATE b : SEMILUNAR CUSP
- velum interpositum: The velum interpositum or tela choroidea superior is a vascular membrane, and is a prolongation of the pia mater into the interior of the brain through the middle part of the transverse fissure. It is of a triangular form,and separates the under surface of the body and posterior pillars of the fornix from the cavity of the third ventricle.
- vena cava filter: Mechanical devices inserted in the inferior vena cava that prevent the migration of blood clots from deep venous thrombosis of the leg.
- venous: (adjective)
1 a : full of or characterized by veins
b : made up of or carried on by veins
2 : of, relating to, or performing the functions of a vein
3 of blood : having passed through the capillaries and given up oxygen for the tissues and become charged with carbon dioxide and ready to pass through the respiratory organs to release its carbon dioxide and renew its oxygen supply : dark red from reduced hemoglobin --compare ARTERIAL 2
- venous angioma: Caput medusae, wedge-shaped appearance with its base at the meninges and its apex directed toward the ventricles, prominent medullary vein drains into a markedly enlarged transcortical cerebral vein, angiogram: normal arterial phase without AV shunting.
- venous angioma: Congenital angioma of the brain composed of abnormal veins, usually those near the ventricular wall. It is often asymptomatic.
- venous sinuses: Venous sinus. A large vein or passage (as the canal of Schlemm) for venous blood.
- venous tumor: See: venous angioma
- Ventral: (adjective)
1 : of or relating to the belly : ABDOMINAL
2 a : being or located near, on, or toward the lower surface of an animal (as a quadruped) opposite the back or dorsal surface
b : being or located near, on, or toward the front or anterior part of the human body
-- ven*tral*ly (adverb)
- ventrical: One of the system of communicating cavities in the brain that are continuous with the central canal of the spinal cord, that like it are derived from the medullary canal of the embryo, that are lined with an epithelial ependyma, and that contain a serous fluid.
- ventricle: A cavity of a bodily part or organ.
- ventricles: See ventricle.
- ventricular system: The ventricular system is a set of structures in the brain continuous with the central canal of the spinal cord. The system comprises four ventricles:
right and left lateral ventricles
Each ventricle contains a choroid plexus that produces cerebrospinal fluid (CSF) used to bathe and cushion the brain and spinal cord within their bony confines.
See: cerebrospinal fluid
- ventriculostomy: (noun)
: the surgical establishment of an opening in a ventricle of the brain to drain cerebrospinal fluid esp. in hydrocephalus
- venus angioma: See: venous angioma
- venusangionoma: This appears to be a misspelling of venous angioma. Please see that entry.
- vermis: Either of two parts of the median lobe of the cerebellum: 1) one slightly prominent on the upper surface -- called also superior vermis; and 2) one on the lower surface sunk in the vallecula -- called also inferior vermis.
- versicolor: Tinea versicolor. A chronic noninflammatory infection of the skin especially of the trunk that is caused by a lipophilic fungus and is marked by the formation of irregular macular patches that often appear lighter than the surrounding area if the skin is tanned and may appear darker than the surrounding skin if the skin is not tanned or black -- called also pityriasis versicolor.
- vertebral: Pertaining to a vertebra (one of the 33 bony segments of the spinal column) or to the vertebral (spinal) column.
- vertical diploplia: See: Trochlear Nerve
- vertigo: Vertigo: Vertigo is a feeling that you are dizzily turning around or that things are dizzily turning about you. Vertigo is usually due to a problem with the inner ear. Vertigo can also be caused by vision problems.
- vestibular: (noun)
: the vestibule of the inner ear together with the end organs and nerve fibers that function in mediating the labyrinthine sense
- vestibulocochlear nerve: The vestibulocochlear nerve is responsible for the sense of hearing and balance (body position sense). The vestibulocochlear nerve is also referred to as cranial nerve VIII.
- vhl: Abbreviation for von Hippel-Lindau Syndrome
- villi: Inflected Form(s): plural vil·li /-"I/
: a small slender vascular process: as a : one of the minute fingerlike processes which more or less thickly cover and give a velvety appearance to the surface of the mucous membrane of the small intestine and serve in the absorption of nutriment and of which each has a central blindly ending lacteal surrounded by blood capillaries and covered with epithelium b : one of the branching processes of the surface of the chorion of the developing embryo of most mammals that are restricted to particular areas or diffusely arranged and over parts of the surface become vascular and help to form the placenta
- Vincristine: An anticancer drug that belongs to the vinca alkaloid family of drugs called mitotic inhibitors.
- viral: (adjective)
: of, relating to, or caused by a virus
-- vi*ral*ly (adverb)
- VIRAL MENINGITIS: Meningitis, viral: Inflammation of the meninges (the tissues that cover the brain and spinal cord) caused by a virus, usually one of the enteroviruses such as the mumps virus or Coxsackievirus. Viral meningitis can be a complication the common childhood diseases, including chickenpox.
Symptoms include fever, severe headache, stiff neck, bright lights hurt the eyes, drowsiness, confusion, and nausea and vomiting. In babies, the symptoms are more difficult to identify. They may include irritability, difficulty in awakening the baby, or poor feeding.
Viral meningitis is usually diagnosed by examination of a sample of spinal fluid obtained with a lumbar puncture (spinal tap).
Viral meningitis is serious but rarely fatal in persons with a normal immune system. Symptoms tend to last from 7 to 10 days. Most patients recover completely. Treatment, if warranted, is by antiviral drugs.
Since the viruses that cause viral meningitis are contagious, viral meningitis can often be prevented by improved hygiene. Viral meningitis is also called aseptic meningitis.
- virchow robin: See: Virchow-Robin spaces
- virchow robin space: See: Virchow-Robin spaces
- virchow robin spaces: See: Virchow-Robin spaces
- virchow robins: See: Virchow-Robin spaces
- virchow-robin space: See: Virchow-Robin spaces
- Virchow-Robin spaces: Virchow-Robin spaces, or enlarged perivascular spaces (EPVS) are spaces that surround blood vessels for a short distance as they enter the brain. Their wall is formed by prolongations of the pia mater. Virchow-Robin spaces are not usually present in the brains of healthy young adults. The presence of Virchow-Robin has been associated with multiple diseases.
- VISUAL CORTEX: a sensory area of the occipital lobe of the cerebral cortex receiving afferent projection fibers concerned with the sense of sight -- called also visual cortex
- visual defect: A problem or distorition with one's vision. Numerous problems can arise with one's vision such as double vision, blurred vision, blind spots, color-blindness and complete blindness to name some of them.
- visual field defect: An incontinuous area in one's vision. This area can be filled with nothing or images that are not really in one's visual field.
- vitamin: (noun)
: any of several fat-soluble vitamins or a mixture of two or more of them whose lack in the animal body causes keratinization of epithelial tissues
- von Hippel-Lindau Syndrome: Von Hippel-Lindau, abbreviated VHL, is a genetic condition involving the abnormal growth of blood vessels in some parts of the body which are particularly rich in blood vessels, including the brain and spinal cord. While blood vessels normally grow like trees, in people with VHL little knots of capillaries sometimes occur. These little knots are called angiomas, or hemangioblastomas.
- von hipple landau: See von Hippel-Lindau Syndrome.
- vonhipple: See von Hippel-Lindau Syndrome.
- vp-16: Also known as Etoposide, one of the mildest chemotherapeutics available at this time. The side effects are minimal and it provides the patient with a high quality of life. Nausea can be easily combated with oral Zofran or Kytril. Hair loss is minimal and as the course progresses hair may regrow while still on treatment. Most of the side effects appear to be transient rather than on-going and do not cause the patient too much discomfort. Although neutropenia occurs quite often it is tolerable and isolation from the community is not required. Click here for more information.
- wallerian degeneration: Wallerian degeneration is a process that results when a nerve fiber is cut or crushed, in which the part of the axon separated from the neuron's cell nucleus degenerates. This is also known as anterograde degeneration.
- well differentiated: Something that is well defined.
- WEN: : SEBACEOUS CYST ; broadly : an abnormal growth or a cyst protruding from a surface especially of the skin
- what controls the 4th ventricle: See: 4th ventricle.
- what is an aneurysm: an abnormal blood-filled dilatation of a blood vessel and especially an artery resulting from disease of the vessel wall
- what is annurism: See: aneurysm.
- white brain: The part of the brain that contains myelinated nerve fibers. The white matter is white because it is the color of myelin, the insulation covering the nerve fibers. The white matter is as opposed to the gray matter (the cortex of the brain which contains nerve cell bodies).
- white matter: Neural tissue that consists largely of myelinated nerve fibers, has a whitish color, and underlies the gray matter of the brain and spinal cord or is gathered into nerves.
World Health Organization
- WHO Classification: Brain tumors are classified into histological grades that generally correlate with biological behavior.
Low-grade tumors (WHO grades I and II) are comprised of neoplastic cells with relatively compact and homogenous nuclei and cytological differentiation reminiscent of their normal cells of origin.
High-grade tumors diverge from the appearance of their cells of origin. For example, anaplastic (less differentiated) astrocytomas (WHO grade III) have atypical nuclei, poorly differentiated cytoplasm and high rates of proliferation as evident by the presence of mitoses.
The most malignant tumors (WHO grade IV) have extremely atypical nuclei and very high mitotic rates, often associated with striking microvascular proliferation and regions of necrosis. The overall probability of survival is substantially lower for patients with high-grade tumors when compared to lower-grade tumors of the same histological type.
- WHO grade: WHO stands for World Health Organization, the entity which developed the widely used and accepted classification system for brain tumors. Brain tumors are graded from low grade (grade I) to high grade (grade IV). The grade of a tumor refers to the way the cells look under a microscope. Cells from higher grade tumors are more abnormal looking and generally grow faster than cells from lower grade tumors; higher grade tumors are more malignant than lower grade tumors. Higher grade tumors may also be referred to as anaplastic, for example, an Anaplastic Astrocytoma is a grade III tumor.
Because they are located in the brain, it is important to recognize that even a low grade brain tumor can be dangerous because, as a tumor in the brain grows, it presses upon normal brain tissues which can cause inflammation and brain swelling. It is therefore very important that both low and high grade tumors be treated as early as possible, even if the treatment is only serial MRIs for low grade tumors.
- WHO I: See: WHO grade
- willis disease: Willis' disease. Diabetes mellitus.
- Wilms' tumor: Also called Wilm's tumor. A malignant tumor of the kidney that primarily affects children.
- wilsons: a hereditary disease that is characterized by the accumulation of copper in the body (as in the liver, brain, or cornea) due to abnormal copper metabolism associated with ceruloplasmin deficiency, that is determined by an autosomal recessive gene, and that is marked especially by liver dysfunction and disease and neurologic or psychiatric symptoms (as tremors, slowness of speech, inappropriate behaviors, or personality changes) -- called also hepatolenticular degeneration -- see KAYSER-FLEISCHER RING
Wilson, Samuel Alexander Kinnier (1877-1937), British neurologist. Wilson enjoyed long-term associations with King's College Hospital and the National Hospital for the Paralyzed and Epileptic, both in London. His neurological studies covered such diverse topics as epilepsy, narcolepsy, speech disorders, apraxia, and pathological laughing and crying. In 1912 he published a monograph on progressive lenticular degeneration, which is now known as Wilson's disease. He was the first to detect the relationship between liver disease and putaminous destruction.
- x-knife: A device which radiates small areas of the brain. The x-knife can focus radiation therapy to a specific small area. Use of this type of radiation therapy allows a patient to receive radiation in smaller doses on repeated occasions and to be treated for tumors that are very close to very critical structures such as the visual nerves, which are sensitive to radiation. The x-knife is often used to remove pieces of the tumor left behind during surgery.
- xanthoastrocytoma: See: pleomorphic xanthoastrocytoma
- xanthoastrocytoma, pleomorphic: A low-grade astrocytic tumor which may exhibit anaplastic features and generally carries a relatively favorable prognosis and should not be classified with other high-grade gliomas, such as anaplastic astrocytoma and glioblastoma multiforme.
- ZD1839: Generic form of Iressa, an experimental drug manufactured by Astra Zeneca, and thought to be an inhibitor of epidermal growth factor receptor (EGFR) in the treatment of advanced squamous-cell head and neck cancers. It may have potential as an adjunct to radiation therapy or in combination with other agents
- Zofran: Anti-emetic (anti-nausea and vomiting drug) for chemotherapy and radiotherapy.
- zygomatic tumor: A tumor involving the area of the side of the face below the eye that forms part of the zygomatic arch and part of the orbit and articulates with the temporal, sphenoid, and frontal bones and with the maxilla of the upper jaw -- called also cheekbone, jugal, malar bone, zygoma.