acetylcholine: a neurotransmitter that allows messages to be passed from neuron to neuron across a synapse; released by cholinergic nerves.

acoustic nerve: the eighth cranial nerve responsible for hearing and balance, also known as the vestibulocochlear nerve.

acoustic neuroma: a benign, slow growing tumor that forms on the sheath of the eighth cranial nerve. This tumor can cause hearing loss, balance problems, and facial palsy.

acromegaly: enlargement of the hands, feet or face in adults due to overproduction of growth hormone; often from a growth hormone-secreting pituitary tumor.

acupuncture: an ancient Oriental system of holistic therapy that can be used to control pain by insertion of fine stainless steel needles into specific areas of the body.

acute: a condition of quick onset lasting a short time, opposite of chronic.

adenoma: a tumor that grows from a gland.

adjunct treatment: a treatment given in addition to another to make each work more effectively.

allograft: a portion of living tissue taken from one person (the donor) and implanted in another (the recipient) for the purpose of fusing two tissues together.

ambulate: a term used by medical personnel to describe a patient’s ability to walk or move around by themselves.

analgesics: a medicine that relieves pain without affecting consciousness, the most common of which is aspirin.

anaplastic: when cells divide rapidly and bear little or no resemblance to normal cells in appearance or function.

anastomosis: the connection of normally separate parts or spaces so they intercommunicate, as between two blood vessels.

anesthesiologist: a doctor who specializes in monitoring your life functions during surgery so that you don’t feel pain.

anesthetic: an agent that causes loss of sensation with or without the loss of consciousness.

aneurysm: a bulge or weakening of an artery wall.

aneurysm clip: a coil-spring device made of titanium used to treat aneurysms.

angiogenesis: the process of developing new blood vessels.

angiogram: a type of X-ray that takes pictures of blood vessels with the help of contrast dye injected via a catheter into the blood stream.

angioplasty: an endovascular procedure to insert a balloon-tipped catheter to enlarge a narrowing in an artery; performed during an angiogram.

ankylosing spondylitis: a chronic inflammatory disease that affects the joints between the vertebrae of the spine, and the joints between the spine and the pelvis. It eventually causes the affected vertebrae to fuse or grow together.

annulus (annulus fibrosis): tough fibrous outer wall of an intervertebral disc.

anterior: from the front.

anterior longitudinal ligament (ALL): a strong fibrous ligament that courses along the anterior surface of the vertebral bodies from the base of the skull to the sacrum.

anticonvulsant: a drug that stops or prevents convulsions or seizures. Used in patients with facial pain to block firing of nerves in order to control pain.

antiepileptic drug (AED): a medication used to control epileptic seizures.

apoplexy: sudden bleeding inside an organ.

arachnoid mater: one of three membranes that surround the brain and spinal cord; the middle web-like membrane.

arterial Doppler study: also known as PVR, this test measures blood flow using ultrasound—a radiation-free test in which high-pitched sound waves are directed toward your arteries then reflected back to form an image.

arteriovenous fistula (AVF) : an abnormal passage or opening between an artery and a vein.

arteriovenous malformation (AVM): a congenital disorder in which there is an abnormal connection between arteries and veins without an intervening capillary bed.

arthritis: joint inflammation caused by infection, immune deficiency (rheumatoid arthritis), or degeneration of the cartilage; causes pain, swelling, redness, warmth, and restricted movement.

astrocytoma: a tumor arising from the supportive cells of the brain called astrocytes. These tumors are a type of glioma and range from slow growing and benign to fast growing and malignant. They are the most common primary CNS tumor, representing about half of all primary brain and spinal cord tumors.

atherosclerosis: a disease of the arterial blood vessels, in which the walls of the arteries become thickened and hardened by plaques. Plaques are composed of cholesterol and other lipids, inflammatory cells, and calcium deposits; also called “hardening of the arteries.”

audiogram: a test of hearing acuity.

aura: a "warning" that a seizure may be imminent, the beginning of a seizure. Auras range from abnormal smells or tastes, to a funny feeling in the stomach, to sounds, colors, or emotional rushes.

autograft (autologous): a portion of living tissue taken from a part of ones own body and transferred to another for the purpose of fusing two tissues together.

automatism: things people do during a seizure in a state of diminished consciousness, such as pulling at their clothes or chewing.

axon: a long process of the nerve cell (neuron) that carries nerve impulses away from the cell body to other nerve cells.

baclofen: a muscle relaxing drug used to treat spasticity; Lioresal.

balloon test occlusion: a test performed during an angiogram in which a balloon is temporarily inflated inside an artery to block the flow of blood. Used to evaluate collateral blood flow to the brain and assess whether a bypass or vessel sacrifice can be safely tolerated.

basal ganglia: a mass of nerve cell bodies (gray matter) located deep within the white matter of the cerebrum. Has connections with areas that subconsciously control movement.

Bell’s palsy: a weakness or paralysis on one side of the face caused by viral or physical damage to the facial nerve.

benign: non cancerous tumor that grows slowly, does not invade nearby tissues or spread, and has distinct boundaries.

bias: a point of view preventing impartial judgment on issues. In clinical studies, blinding and randomization minimize bias.

bilateral: occurring on both sides of the body.

biofeedback: a technique of learning how to control certain body functions by monitoring brain waves, muscle tension, blood pressure, etc.

biopsy: a sample of tissue cells for examination under a microscope to determine the existence or cause of a disease.

blind: a randomized clinical trial is "blind" when the participants do not know to which group (experimental or control) they are assigned.

bone graft: bone harvested from one's self (autograft) or from another (allograft) for the purpose of fusing or repairing a defect.

bone scan: a nuclear medicine test that detects areas of increased or decreased bone metabolism. A radioactive material is injected into the bloodstream where it collects in the bones of the body and is detected by a gamma camera. The test is commonly used to diagnose tumors, infections, or fractures of the bone.

bone spurs: bony overgrowths that occur from stresses on bone, also called osteophytes.

Botox (Botulinum Toxin Type A): A toxin injected into your facial muscles that prevents them from contracting. Used both as a treatment for hemifacial spasm and cosmetically to reduce the appearance of wrinkles.

brachytherapy: a type of radiation therapy where capsules containing radioactive substances are surgically implanted into the tumor to deliver radiation; also called internal radiotherapy.

bradykinesia: slowness of movement, impaired dexterity, decreased blinking, drooling, expressionless face.

brainstem: connects the upper brain to the spinal cord; responsible for autonomic functions such as breathing and heart rate.

burr hole: a small dime-sized hole made in the skull.

cancellous bone: (sometimes called trabecular bone) the spongy bone found beneath the hard outer bone that is rich with bone-growing proteins.

cancer: generic term for more than 100 different diseases caused by uncontrolled, abnormal growth of cells. Cancer cells can invade and destroy normal tissue, and can travel through the bloodstream and lymphatic system to reach other parts of the body.

catheter: a thin flexible tube made of rubber or plastic used to insert or remove fluids from the body.

cauda equina: the bundle of nerves at the end of the spinal cord that supply the muscles of the legs, bladder, bowel and genitals.

cauda equina syndrome: dull pain and loss of feeling in the buttocks, genitals, and/or thigh with impaired bladder and bowel function; caused by compression of the spinal nerve roots.

caudate nucleus: part of the basal ganglia involved with voluntary control of movement.

cavernous malformation: abnormal collection of blood vessels with no well-defined feeding arteries or draining veins.

cerebellum: part of the brain responsible for balance and muscle control for movement.

cerebral bypass: an operation in which a surgeon creates a new pathway for the movement of fluids and/or other substances in the brain.

cerebrospinal fluid (CSF): a clear fluid produced by the choroid plexus in the ventricles of the brain. CSF bathes the brain and spinal cord, giving them support and buoyancy to protect from injury.

cerebrospinal fluid (CSF) leak: the fluid surrounding the brain can escape through a hole in the dura lining the skull. In 1% of transsphenoidal cases, a clear watery discharge from the nose, postnasal drip, or excessive swallowing occurs; may require surgery to patch the leak.

cerebrovascular insufficiency: an insufficient blood flow to the brain. The most common cause of decreased blood flow is atherosclerosis of the arteries that supply blood to the brain.

cervical: the neck portion of the spine made up of seven vertebrae.

chemotherapy: treatment with toxic chemicals (e.g., anticancer drugs).

chiropractic manipulation: a system of complimentary medicine that attempts to treat diseases and pain by adjusting alignment of the bones, especially in the back.

cholesterol: a fat-like substance that is made by the human body and eaten in animal products. Cholesterol is used to form cell membranes and process hormones and vitamin D. High cholesterol levels contribute to the development of atherosclerosis.

chondroma: a rare, slow growing, benign tumor arising at the base of the skull, especially in the area near the pituitary gland.

chondrosarcoma: a rare, malignant bone tumor that grows from cartilage cells.

chordoma: a rare, bone tumor arising from primitive notochord cells; usually occurs at the base of the spine (sacrum) or at the skull base (clivus).

chronic: a condition of slow progression and continuing over a long period of time, opposite of acute.

coiling: a procedure, performed during an angiogram, in which platinum coils are inserted into an aneurysm.

collateral vessels: a branch of an artery or vein used as an accessory to the blood vessel from which it arises; often develop to shunt blood around a blockage.

congenital: existing before or at birth.

contrast agent: a liquid (usually iodine or gadolinium) that is injected into your body to make certain tissues more visible during diagnostic imaging (angiography, CT, myelogram, MRI).

control group: the group that receives standard treatment.

cooperative groups: networks of organizations and researchers at academic hospitals and community practices that collaborate to conduct research in their medical specialty.

corpectomy: a type of spine surgery in which a major portion of the bony vertebral body is removed and is replaced with a bone graft.

cortical bone: outer layer of dense, compact bone.

cortical mapping: direct brain recording or stimulation to identify language, motor, and sensory areas of the cortex.

corticosteroid: a hormone produced by the adrenal gland or synthetically. Regulates salt and water balance and has an anti-inflammatory effect.

cortex: the outer layer of the brain containing nerve cell bodies.

cranial nerves: the 12 pairs of nerves that originate in the brainstem and carry sensory and motor information to organs in the head and body.

craniectomy: surgical removal of a portion of the skull.

craniopharyngioma: a benign tumor that grows from cells near the pituitary stalk.

craniotomy: surgical opening of a portion of the skull to gain access to the intracranial structures and replacement of the bone flap.

CT (computed tomography) scan: a type of diagnostic X-ray that views anatomical structures of the brain and spine, especially bones, soft tissues and vessels. Images are viewed in "slices," similar to an MRI.

Cushing's disease: an endocrine disease caused by increased levels of cortisol in the body; often from an adrenocorticotropic hormone (ACTH)-secreting pituitary tumor. Hallmark signs include a fatty hump between the shoulders, a rounded face, and pink or purple stretch marks on the skin. Also caused by excessive use of corticosteroid medication.

cyst: a fluid-filled mass, usually enclosed by a membrane.

decompression: opening or removal of bone to relieve pressure and pinching of the spinal nerves.

degenerative arthritis: the wearing away of cartilage that cushions joints in the hands, feet and spine. Bone spurs can develop where the joints rub together resulting in limited motion.

dendrite: the “arms” of a nerve cell that connect with the axons to transmit impulses toward the cell body.

depression: a mood disorder characterized by feelings of extreme sadness and hopelessness that interferes with a person's ability to function, feel pleasure, or maintain interest.

diabetes insipidus: a disorder in which there is an abnormal increase in urine output, fluid intake, and often thirst. Caused by a decrease in vasopressin hormone due to damage of the posterior pituitary lobe.

diathermy: the use of high-frequency alternating current to produce heat in parts of the body. The heat generated increases blood flow and can be used to treat deep pain associated with rheumatic and arthritic conditions.

differentiation : refers to how developed cancer cells are in a tumor. Well-differentiated tumor cells resemble normal cells and tend to grow and spread at a slower rate than undifferentiated, which lack the structure and function of normal cells and grow uncontrollably.

diplopia: double vision.

disc (intervertebral disc): a fibrocartilagenous cushion that connects any two adjacent vertebrae in the backbone or spine.

discectomy: a type of surgery in which herniated disc material is removed so that it no longer irritates and compresses the nerve root.

discogenic pain: pain arising from degenerative changes in the intervertebral discs.

discogram: a type of diagnostic x-ray that views intervertebral discs by inserting contrast agent into the disc space.

disconnection syndrome: the interruption of information transferred from one brain region to another.

dopamine: a neurotransmitter in the brain that allows messages to be passed from neuron to neuron across synapses.

Doppler ultrasound: a noninvasive test that uses reflected sound waves to evaluate blood as it flows through a blood vessel.

dorsal columns: white matter tracts located in the posterior portion of the spinal cord that transmit sensory information to the brain.

double-blinded study: a clinical trial in which neither medical staff nor participants know which therapy the participant will receive.

dura mater: a tough, fibrous, protective covering of the brain.

dysesthesia: troublesome or bothersome numbness.

dyskinesia: abnormal involuntary movements caused by high levels of antiparkinson medication.

dystonia: a movement disorder that causes sustained muscle contraction producing repetitive movements or abnormal postures. Spasms can often be controlled with sensory tricks to suppress the movement.

EC-IC bypass: acronym stands for extracranial – intracranial bypass procedure in which an artery from outside the skull is attached to an artery inside the skull through a craniotomy.

edema: tissue swelling caused by the accumulation of fluid.

efficacy: the ability of a drug or treatment to produce a desired result. A drug passes efficacy trials if it is effective at the dose tested and against the illness for which it is prescribed.

Ehlers-Danlos IV: a genetic disorder in which connective tissue in the intestines, arteries, uterus, and other hollow organs may be unusually weak, leading to organ or blood vessel rupture.

electrode: a conductor that carries current. Can be used for diagnostic testing to receive and record electrical activity of nerves or can be used for therapy to deliver a heating current to destroy nerve fibers.

electromyography (EMG): a test to study muscles and nerves for abnormal patterns of electrical activity. Small needles, or electrodes, are placed in your muscles creating light electrical shocks are given to the muscle and the results are recorded on a special machine.

embolus: (plural emboli) a blood clot or other substance such as air or fat, which is carried in the bloodstream from another site until it blocks a blood vessel.

embolization: the insertion of material, coils or glue, into an aneurysm so blood can no longer flow through it.

endarterectomy: a surgical procedure in which material occluding the carotid artery is cleaned out, thereby restoring normal blood flow to the brain and preventing a stroke.

endocrinologist: a doctor who specializes in treating hormonal/glandular disorders (e.g., pancreas, pituitary).

endorphin: a natural hormone produced by the brain that produces a euphoric pain relieving effect similar to opiates.

endovascular: relating to a procedure in which a catheter containing medications or miniature instruments is inserted through the skin into a blood vessel for the treatment of vascular disease.

ependymoma: a benign tumor that grows from the ependyma cells lining the ventricles.

epidermoid: a benign, congenital tumor arising from ectodermal cells; also called pearly tumor.

epidural space: the space between the walls of the vertebral canal and the dura mater that is filled with fat and small blood vessels.

epidural steroid injection (ESI): an injection of both a long-lasting steroid "cortisone" and an anesthetic numbing agent into the epidural space of your spine. The epidural space is the area between the protective covering of the spinal cord and the bony vertebrae.

epilepsy: a chronic disorder marked by repeated seizures causing a sudden loss or change of consciousness and convulsions or muscle spasms.

epileptologist: a neurologist who specializes in the treatment of epilepsy.

essential tremor: involuntary rhythmic tremors of the hands and arms occurring both at rest and during purposeful movement.

extramedullary: located outside the medulla substance of the spinal cord.

facet joints: joints located on the top and bottom of each vertebra that connect the vertebrae to each other and permit back motion.

facet rhizotomy: a procedure that uses a radiofrequency current to deaden the nerves surrounding the facet joint and prevent pain signals from reaching the brain.

facial nerve (the seventh cranial nerve): a sensory and motor nerve that sends signals to your facial muscles, taste buds on the front of your tongue, sublingual salivary glands, and lacrimal glands. A small branch goes to your ear to help regulate hearing.

facial palsy: paralysis of the facial muscles on one side.

familial: tending to occur repeatedly in family members, but is not genetic (inherited). Might indicate a susceptibility or a common environmental influence.

fibromuscular dysplasia: abnormal cell growth in the artery walls that causes narrowing and a “string of beads” appearance; usually affects arteries of the kidneys and brain.

fistula: the abnormal channel between the artery and vein in an AVM.

fluoroscopy: an imaging device that uses x-ray or other radiation to view structures in the body in real time, or “live”. Also called a C-arm.

focal: limited to one specific area.

foramen (intervertebral foramen): the opening or window between the vertebrae through which the nerve roots leave the spinal canal.

foraminotomy: surgical enlargement of the intervertebral foramen through which the spinal nerves pass from the spinal cord to the body. Performed to relieve pressure and impingement of the spinal nerves.

fractionated radiotherapy: delivering the radiation dose over multiple sessions.

fusion: to join together two separate bones into one to provide stability.

gadolinium: a type of contrast agent used during MRI.

ganglion: a group of nerve cell bodies located at the root of a nerve.

generalized seizure: a seizure involving the entire brain.

gigantism: excessive growth and height in children caused by overproduction of growth hormone; often from a growth hormone-secreting pituitary tumor.

glial cells: cells of the nervous system that support the neurons. There are 10-50 times more glial cells in the brain than neurons.

glial scar: a physical and molecular barrier surrounding the injured area of the spinal cord that may prevent axons from regenerating.

glioblastoma multiforme (GBM): these tumors, sometimes called high-grade or grade IV astrocytomas, grow rapidly, invade nearby tissue, and contain cells that are very malignant.

glioma: a large category of primary brain tumors that originate from glial cells. There are many types of gliomas; see astrocytoma, glioblastoma multiforme, mixed glioma, optic nerve glioma.

globus pallidus interna (GPI): nuclei in the brain that regulate muscle tone; part of the basal ganglia.

glomus jugulare: a very rare, slow growing, benign tumor that invades the temporal bone.

glossopharyngeal nerve: a nerve originating from the brainstem that supplies feeling and movement to the tongue and throat.

glossopharyngeal neuralgia: A painful disorder of the ninth cranial nerve (glossopharyngeal nerve). Irritation of this nerve causes intense pain on one side of the throat near the tonsil area that can radiate to the ear.

glutamate: a neurotransmitter that allows messages to be passed from neuron to neuron across a synapse.

glucose: a simple sugar that is a source of energy for the body and the only source of energy for the brain.

glycerol: a sweet, oily fluid that can be injected into a nerve to destroy its pain-producing portion.

hamstring: a group of 3 muscles that run down the back of the thigh.

hematoma: a blood clot.

hemangioblastoma: benign tumor-like mass that forms from blood vessels and is often cystic; associated with von Hippel-Lindau disease.

hemangioma: a benign tumor that forms from blood vessels in the brain or spinal cord.

hemangiopericytoma: a rare tumor, grade II or grade III, different from the meningioma, although rising from the same cells.

hemifacial spasm: an irritation of the seventh cranial nerve (facial nerve) causing involuntary contraction of the muscles on one side of the face, also known as tic convulsif. Can sometimes cause pain behind the ear and loss of hearing.

hemorrhage: external or internal loss of blood from damaged blood vessels. Hemorrhage is stopped by blood clotting.

hemorrhagic stroke: stroke caused by the rupture of a blood vessel in the brain.

heparin: an anti-clotting medication.

herniate: to protrude through the wall of the cavity in which it is normally enclosed. Rupture.

herniated disc: a condition in which the gel-like center of an intervertebral disc ruptures through the tough disc wall irritating surrounding nerves and causing pain.

hippocampal atrophy: a wasting or decrease in the hippocampus size causing seizures.

hippocampus: a region in the temporal lobe of the brain that is associated with learning and memory.

hormone: a chemical substance produced in the body that controls and regulates the activity of certain cells or organs.

hunchback: see kyphosis.

hydrocephalus: an abnormal build-up of cerebrospinal fluid usually caused by a blockage of the ventricular system of the brain. Increased intracranial pressure can compress and damage brain tissue. Also called “water on the brain.”

hyperextension: extending a joint or limb beyond its normal limit.

hypermetabolism: faster than normal metabolism.

hyperthyroidism: increased heart rate, weight loss, nervousness, and sleeplessness caused by excess thyroid hormone; can be caused by thyroid-stimulating hormone (TSH)-producing pituitary tumor.

hypometabolism: slower than normal metabolism.

hypothalamus: a part of the brain that regulates pituitary hormone responses by secreting releasing factors or inhibiting factors, depending on the needs of the body.

ictal: that which happens during a seizure.

idiopathic: of unknown cause.

image-guided surgery: use of preoperative CT or MRI scans and a computer workstation to guide surgery.

immunotherapy: treatment designed to improve or restore the immune system's ability to fight infection and disease.

infarct: an area of dead tissue caused by a blockage of its blood supply.

inherited: to receive from a parent or ancestor by genetic transmission.

Institutional Review Board (IRB): a committee of scientists, doctors, and consumers at each health care facility where a clinical trial takes place. IRBs review and must approve protocols for all clinical trials. They check to see that the study is well designed, does not involve undue risks, and includes safeguards for patients.

intensity modulated radiation therapy (IMRT): the intensity of the radiation beam can be changed during treatment to spare adjoining normal tissue and increase the dose to the tumor.

interbody cage: a device made of titanium, carbon-fiber, or polyetheretherketone (PEEK) that is placed in the disc space between two vertebrae. It has a hollow core packed with bone morsels to create a bone fusion.

interbody fusion: a procedure in which a device, packed with bone fragments, is screwed into the space between two vertebral bodies. The bone fragments join with the bone of the vertebrae to create a solid joint and reduce movement at the painful segment.

interictal: that which happens between seizures.

interstitial radiation: implantation of radioactive seeds into a tumor: also called brachytherapy.

intervertebral foramen: the hole through which the spinal nerve exits the spinal canal.

intracerebral hemorrhage (ICH): bleeding directly into the brain tissue; may cause a stroke.

intracranial: within the skull.

intracranial pressure (ICP): pressure within the skull. Normal ICP is 20mm HG.

ICP monitor: a device used to measure intracranial pressure inside the brain.

intractable: difficult to control.

intradural-extramedullary: lesion located within the covering of the spinal cord (the dura) but outside the substance of the spinal cord.

intramedullary: located within the spinal cord itself.

intrathecal space: the space surrounding the spinal cord through which cerebral spinal fluid (CSF) flows; also called the subarachnoid space.

iodine: a non-metallic element used in contrast agent that makes vessels and tissues show up on diagnostic imaging (angiogram, CT, myelogram).

ischemia: a low-oxygen state usually due to obstruction of the arterial blood supply or inadequate blood flow leading to hypoxia in the tissue.

ischemic stroke: stroke caused by an interruption or blockage of oxygen-rich blood flow to an area of the brain; caused by a blood clot, atherosclerosis, vasospasm, or reduced blood pressure.

kyphoplasty: a minimally invasive procedure used to treat vertebral compression fractures by inflating a balloon to restore bone height then injecting bone cement into the vertebral body.

kyphosis: abnormal curve of the thoracic spine, also called hunchback.

labyrinth: part of the inner ear responsible for balance.

lamina: flat plates of bone originating from the pedicles of the vertebral body that form the posterior outer wall of the spinal canal and protect the spinal cord. Sometimes referred to as vertebral arch.

laminectomy: surgical removal of the laminae or vertebral arch of the vertebra to remove pressure on the spinal cord.

laminotomy: surgical cutting of the laminae or vertebral arch of the vertebra.

laser: a device that emits a narrow intense beam of energy to shrink and cut tissue.

LDL cholesterol: Low-density lipoprotein cholesterol is the primary cholesterol molecule. High levels of LDL, nicknamed "bad" cholesterol, increase the risk of atherosclerosis.

L-DOPA: a synthetic form of dopamine used in anti-parkinson medication.

lead: a small medical wire that carries electrical current.

lesion: a general term that refers to any change in tissue, such as tumor, blood, malformation, infection or scar tissue.

ligament: strong band of white fibrous connective tissue that joins bones to other bones or to cartilage in the joint areas.

linear accelerator (LINAC) : a machine that creates a high-energy radiation beam, using electricity to form a stream of fast-moving subatomic particles.

lipoma: a rare, benign tumor composed of fat tissue, commonly located in the corpus callosum.

lobectomy: surgical removal of a lobe of the brain.

lordosis: increased curvature of the lumbar spine that tends to make the buttocks more prominent, also called swayback.

lumbar: lower portion of the spine made up of 5 vertebrae; connects with the fused bones of the sacrum below.

lumen: the inside diameter of a blood vessel or hollow organ.

lymphoma: a rare tumor arising from lymph cells; may metastasize to the brain from lymphoma tumor elsewhere in the body.

Magnetic Resonance Imaging (MRI): a diagnostic test that uses a strong magnet to view tissues in your body and displays them in a series of "slices."

malignant: cancerous tumor that grows quickly, invades other tissues, and has irregular boundaries.

Marfan's syndrome: a genetic disorder in which patients develop skeletal defects in long bones, chest abnormalities, curvature of the spine, and circulatory defects.

mass effect: damage to the brain due to the bulk of a tumor, the blockage of fluid, and/or excess accumulation of fluid within the skull.

meninges: three membranes (pia mater, arachnoid mater, and dura mater) that surround the brain and spinal cord.

meningioma: a tumor that grows from the meninges, the membrane that surrounds the brain and spinal cord.

metastasis: in cancer patients, the spreading of malignant cells.

metastatic: cancerous tumor that has spread from its original source through the blood or lymph systems.

microcatheter: a small catheter, about the size of a string of spaghetti, used to discharge coils into an aneurysm.

micrographia: small handwriting seen in Parkinson's Disease.

microvascular decompression (MVD): a surgical procedure to relieve symptoms caused by cranial nerve compression; a tiny sponge is inserted between the compressing vessel and the nerve.

minimally invasive surgery: use of technology (e.g., endoscopes, cameras, image-guidance systems, robotics) to operate through small, keyhole incisions in the body.

monotherapy: treatment with only one drug.

morphine: a potent narcotic drug used to treat severe and persistent pain.

Moyamoya disease: a narrowing of the internal carotid arteries at the base of the brain that can eventually result in complete blockage and stroke. To compensate for the narrowing arteries, the brain creates collateral blood vessels in an attempt to deliver oxygen-rich blood to deprived areas of the brain.

Moyamoya syndrome: a condition with moyamoya-like changes to the internal carotid arteries but caused by a known disease.

MRI (Magnetic Resonance Imaging): a diagnostic test that uses a strong magnet to view tissues in your body and displays them in a series of "slices."

multi-center trials: clinical trials that are conducted at many treatment centers at the same time.

multiple myeloma: a cancer of plasma cells, the antibody-producing cells normally present in the bone marrow.

multiple sclerosis: a chronic degenerative disease of the central nervous system in which the myelin (sheath) surrounding the nerves is destroyed.

MVD (microvascular decompression): a surgical procedure to relieve symptoms caused by cranial nerve compression; a tiny sponge is inserted between the compressing vessel and the nerve.

myelin: a fatty material that forms a protective sheath around the axon of nerve cells.

myelogram: a diagnostic test in which a special dye is injected into the space around the spinal cord causing the nerves to show up white on an X-ray.

myelopathy: a broad term referring to spinal cord dysfunction of any cause. Some processes that lead to myelopathy include: transverse myelitis, injury, arthritis, vascular malformation, vertebral fracture from osteoporosis infection or malignancy, or syrinx (an enlarged cyst within the spinal cord).

nasal splints: small, thin plastic material placed in the nose after surgery to prevent adhesion scars from forming in the nose.

necrosis: dead cells.

nerve conduction velocity (NCV): a test to study nerves for abnormal patterns of electrical activity. Small electrode pads are placed on your skin along a nerve path. Light electrical shocks are given to the nerve and the results are recorded on a special machine.

neuralgia: severe nerve pain caused by nerve compression or the breakdown of the protective myelin sheath surrounding a nerve. This disrupts the normal signal of the nerve and causes pain which begins as "pins and needles" followed by an intense burning, jabbing, or electrical shock sensation that can last several minutes.

neuritis: inflammation of a nerve or nerves.

neurofibroma: a benign tumor that grows from the fibrous covering of a nerve. Related to the inherited disorder neurofibromatosis.

neurogenic claudication: a pain syndrome in the back and legs aggravated by walking and relieved by sitting or bending forward.

neurogenic keratitis: inflammation of the cornea, which is the transparent outermost layer of the eyeball.

neuron: basic unit of the nervous system, composed of a cell body, dendrites, and axon; also called a nerve cell.

neurotransmitter: a chemical substance that allows for the transmission of electrical impulses from one nerve cell to another across synapses. Some neurotransmitters include: acetylcholine, noradrenaline, dopamine, serotonin, gamma-aminobutyric acid and glutamate.

nidus: the central part of an AVM.

non-steroidal anti-inflammatory medications (NSAIDs): drugs used to reduce inflammation and relieve pain. They mainly inhibit the body's ability to synthesize prostaglandins.

nucleus (nucleus pulposus): soft gel-like center of an intervertebral disc.

numbness: a lack of sensation or the inability to feel anything when the skin is touched.

occlusion: an obstruction or closure of a passageway or vessel.

oculoplastic surgeon: a doctor who specializes in surgery of the eye and face.

oligodendroglioma: a tumor that grows from the support cells (oligodendroglia) of the brain that produce myelin, the fatty covering around nerve cells.

orthotic: any device applied to or around the body in the care of physical impairment or disability.

orthotist: a medical professional who specializes in making custom molded braces and prostheses (artifical limbs).

osteoblasts: the bone-building cells in bone.

osteoclasts: the bone-removing, or resorption, cells in bone.

osteoporosis: a depletion of calcium in the bones making them weak, brittle, and prone to fracture. Common in elderly women after menopause. Can be prevented early in life with calcium and regular exercise to stimulate bone metabolism.

osteophyte: bony overgrowths that occur from stresses on bone, also called bone spurs. Often relates to osteoarthritis.

osteoblastoma: a non-cancerous bone tumor that grows in the posterior portion of the spine. Symptoms include long-lasting pain, swelling and tenderness. Pain stops when it is surgically removed.

osteoid osteoma: a smaller, non-cancerous type of osteoblastoma that causes increased pain at night. This tumor is easy to treat with surgery or radio-frequency ablation.

osteomyelitis: a bone infection caused by bacteria.

Paget's disease: also known as osteitis deformans, a bone disease in which normal bone is destroyed and then replaced with thickened, weaker, softer bone. This weaker bone easily bends and deforms. Most often affects the pelvis, thoracic and lumbar spine, skull, femur, tibia, fibula, and clavicles.

palliative: to alleviate without curing.

papaverine: a vasodilator drug used to relax blood vessels during vasospasm.

paraplegia: paralysis of both legs and lower body below the arms indicating an injury in the thoracic or lumbar spine.

Parkinson's Disease (PD): a degenerative, progressive neurologic disorder that affects nerve cells in deep parts of your brain that are responsible for relaying messages that plan and control body movement. Symptoms include tremor, slowness of movement, stiffness, and balance problems.

paroxysmal: an adjective used to describe the uncontrollable and sudden twitching of the face.

pars interarticularis: the narrow strip of bone between the superior and inferior facets of the vertebra.

partial seizure: a seizure involving only a portion of the brain.

pedicle: the thin, bony bridge that connects the vertebral body with the outer processes.

percutaneous: by way of the skin. (e.g., injection).

perfuse: to force blood or other fluid to flow from the artery through the vascular bed of a tissue.

peripheral nerve stimulation: a pain management system in which specific nerves are stimulated rather than the general area of the spinal cord.

pituitary adenoma: a tumor arising from cells in the pituitary gland; tumor may be hormone-secreting (prolactin, adrenocorticotropic, growth hormone) or not.

placebo: an inactive pill, liquid, or powder that has no treatment value.

PNET (primitive neuroectodermal tumor): a tumor which appears identical under the microscope to the medulloblastoma, but occurs primarily in the cerebrum and most frequently occurs in very young children.

polycystic kidney disease: a genetic disorder in which patients develop multiple cysts on the kidneys; associated with aneurysms of blood vessels in the brain.

positron: an electrically charged particle that has the opposite charge as an electron. It reacts with an electron to produce gamma rays.

positron emission tomography (PET): a diagnostic test using nuclear medicine in which tissue function can be imaged. Damaged tissues have reduced metabolic activity; therefore, gamma radiation from these areas is reduced or absent.

posterior: from the back.

posterior longitudinal ligament (PLL): a strong fibrous ligament that courses along the posterior surface of the vertebral bodies within the spinal canal from the base of the skull to the sacrum.

posterolateral: behind and to one side.

pressure sores: injured areas of skin or tissue caused by lying or sitting in one position too long.

primitive neuroectodermal tumor (PNET) : a tumor which appears identical under the microscope to the medulloblastoma, but occurs primarily in the cerebrum and most frequently occurs in very young children.

progressive supranuclear palsy: a degenerative, progressive neurologic disorder that affects nerve cells in deep parts of your brain causing motor disturbances similar to Parkinson's. Notable symptom is the loss of ability to move the eyes to look downward.

prolactin: a hormone that helps regulate sexual function, including stimulating milk production.

prolactinoma: a benign pituitary tumor that overproduces the hormone prolactin. Too much prolactin causes abnormal milk production in the breasts, lack of menstruation, infertility, and decreased sex drive.

pseudomeningocele: an abnormal collection of cerebrospinal fluid (CSF) that communicates with the CSF space around the brain or spinal cord. Unlike a meningocele, the fluid has no surrounding membrane but is contained in a cavity within the soft tissues.

quadriplegia: paralysis of both legs and arms indicating an injury to the cervical spine.

radiation: high-energy rays or particle streams used to treat disease.

radiculopathy: refers to any disease affecting the spinal nerve roots. Also used to describe pain along the sciatic nerve that radiates down the leg.

radiofrequency: radiation used in MRI whose waves are in the frequency range of 300 MHz to 3 kHz.

radiofrequency rhizotomy: A procedure used to treat facial neuralgias by using radiant energy of a certain frequency (radiofrequency) to destroy the pain-producing portion of the nerve (rhizotomy).

radiolabel: the technique of attaching, or "tagging", a radioactive molecule to another molecule (such as a protein) so that it can be identified in the body. The radiolabeled substance emits positrons that can be picked up by a special scanner.

radiologist: a doctor who specializes in reading X-rays and other diagnostic scans.

radiology department: rooms designated for examining and imaging the body by use of x-rays or magnetic fields.

radioresistant: resistant to radiation therapy.

radiosensitive: responsive to radiation therapy.

radiotherapy: high-energy rays or particle streams used to treat disease.

randomization: a method used to prevent bias in research. People are assigned by chance to either the treatment or control group, like the flip of a coin.

recurrence: the return of symptoms or the disease itself.

reflex: an automatic or involuntary reaction to a stimulus.

resection: surgical removal of a tumor or malformation.

residual tumor: tumor remaining after surgery.

revascularization: to restore blood supply to an organ by means of a blood vessel graft.

rhizolysis: cutting or destroying of a group of cells (e.g., nerve cells) for the relief of pain.

rhizotomy: cutting or destroying portions of nerve roots for the relief of pain.

sacral: the five fused vertebrae at the base of the spine that provide attachment for the iliac (hip) bones and protect the pelvic organs.

schwannoma (also called neuroma): a tumor arising from Schwann cells that produce myelin.

sciatic nerve: nerve located in the back of the leg which supplies the muscles of the back of the knee and lower leg and sensation to the back of the thigh, part of the lower leg, and the sole of the foot.

sciatica: pain that courses along the sciatic nerve in the buttocks and down the legs. Usually caused by compression of the 5th lumbar or 1st sacral spinal nerves.

scoliosis: an abnormal side-to-side curvature of the spine.

seizure: uncontrollable convulsion, spasm, or series of jerking movements of the face, trunk, arms, or legs.

seizure focus: a specific area of the brain where seizures begin.

sella (sella turcica): a depression on the upper surface of the sphenoid bone, lodging the pituitary gland.

seroma: a mass formed by the collection of tissue fluids following a wound or surgery.

shunt: a drainage tube to move cerebrospinal fluid from inside the ventricles of the brain into another body cavity such as the abdomen.

single-center clinical trials: trials initiated by one researcher that are only available at one center.

skull base surgeon: a doctor with special training to perform complex craniotomies at the base of the skull.

spasticity: severe muscle rigidity and spasms caused by damage to motor pathways; makes movement of the arms and legs difficult.

sphenoid sinus: an air-filled, mucous-lined cavity in the skull located behind the nose and between the eyes.

spinal canal: the hollow space within the bony vertebrae of the spine through which the spinal cord passes.

spinal cord: part of the central nervous system enclosed and protected by the spinal vertebrae; conducts messages, or impulses, back and forth between your brain and body to control sensation and movement.

spinal hygroma: an accumulation of cerebrospinal fluid under the skin, which produces a visible swelling, caused by leakage around a catheter, drain, or shunt.

spinal instability: abnormal movement between two vertebrae that can cause pain or damage the spinal cord and nerves.

spinal stenosis: the narrowing of the spinal canal and nerve-root canal along with the enlargement of the facet joints.

spinothalamic tracts: a group of nerve fibers that transmit the feeling of pain through the spinal cord to the brain.

spondylolisthesis: when one vertebra slips forward on another, usually at the fifth lumbar vertebra and sacrum.

spondylolysis: a weakness or fracture between the upper and lower facets of a vertebra, an area called the pars interarticularis.

spondylosis: a spinal condition resulting from degeneration of the intervertebral discs causing narrowing of the disc space and the presence of bone spurs. Also called degenerative disc disease.

status epilepticus: a seizure that lasts more than 5 minutes and requires immediate medical attention due to lack of oxygen to the brain.

stent: a tube-like device that is inserted into a vessel or passageway to keep it open.

stereotactic: a precise method for locating deep brain structures by the use of 3-dimensional coordinates.

steroid: A large group of chemical substances related in structure to one another and each containing the same chemical backbone. Many hormones, body constituents, and drugs are steroids. Examples: drugs used to relieve swelling and inflammation such as prednisone, vitamin D, and the sex steroids such as testosterone.

striatum (corpus striatum): part of the basal ganglia involved with the subconscious regulation of movement.

stroke: a condition caused by interruption of the blood supply to the brain; may cause loss of ability to speak or to move parts of the body.

subarachnoid space: the space between the pia and arachnoid mater of the brain and spinal cord that contains cerebrospinal fluid (CSF).

subarachnoid hemorrhage: bleeding in the space surrounding the brain; may cause a stroke.

substantia nigra: a group of cells in the brain where dopamine is produced.

subthalamic nucleus (STN): a group of cells below the thalamus that is linked to the basal ganglia.

swayback: see lordosis.

synapse: the tiny gap between two nerve cells; across which impulses pass by release of neurotransmitters. Some brain cells have more than 15,000 synapses.

syncope: a fainting spell caused by an abrupt reduction of blood flow to the brain.

syringomyelia: a chronic progressive disease of the spinal cord caused by an obstruction of normal cerebrospinal fluid (CSF) flow that redirects the fluid into the spinal cord to form a syrinx.

syrinx: a cavity filled with cerebrospinal fluid (CSF) that expands and elongates over time, destroying the center of the spinal cord.

telemetry: the method for adjusting the settings on an implanted device by using radio or other remote signals.

thalamus: a relay station for all sensory messages that enter the brain; part of the basal ganglia.

thoracic: middle portion of the spine made up of 12 vertebrae.

thrombolysis: to break down or dissolve a clot.

thrombus: a blood clot.

tic douloureux: French for trigeminal neuralgia.

tingling: a prickling sensation or “pins-and-needles” sensation, like when your foot falls asleep, that is an indication of damage or irritation to the nerves in that area.

tinnitus: ringing in the ears. 

tissue plasminogen activator (t-PA): a thrombolytic "clot-buster" drug used to reduce the severity of ischemic stroke if given within three hours of stroke onset; can be given intravenously or by arterial catheter, but not by mouth.

titanium: a strong, low-density, highly corrosion-resistant metal alloy.

tomography: the technique of using rotating X-rays to capture an image at a particular depth in the body, bringing those structures into sharp focus while blurring structures at other depths.

tracer: a substance, usually radioactively labeled, which is injected into your body and can be followed to gain information about metabolic processes.

tracts: a group of nerve fibers that pass from one part of the brain or spinal cord to another, forming a pathway.

traction: a method for relieving pressure on the spine by using a system of weights and pulleys.

transcranial doppler (TCD): an ultrasound device used to measure blood flow through arteries in the brain.

transient ischemic attack (TIA): a “mini” stroke caused when blood flow to the brain is temporarily interrupted and then restored; causes no permanent brain damage.

translaminar: through the lamina.

trigeminal nerve: a nerve originating within the brain that supplies feeling and movement to the face. The trigeminal nerve has three divisions: ophthalmic (V1), gives sensation to the forehead and eyes; maxillary (V2), gives sensation to the cheek, under the eye, around the nose; and mandibular (V3), gives sensation to the jaw.

trigeminal neuralgia: a painful disorder of the fifth cranial nerve (trigeminal nerve). Irritation of this nerve can cause intense pain that usually affects one side of the face usually in the forehead, cheek, jaw, or teeth.

trigger zones: small areas that produce intense pain if stimulated, usually located near the nose, lips, eyes, or ears.

tumor: an abnormal growth of tissue resulting from uncontrolled multiplication of cells and serving no physiological function. A tumor can be benign or malignant.

ultrasonic aspirator: a surgical tool that uses a fine jet of water, ultrasonic vibration, and suction to break up and remove lesions.

ultrasound: soundwaves of extremely high frequency which reflect off body structures to create a picture. Can also be used as a form of medical treatment to break up kidney stones or treat joint pain.

vagus nerve: a cranial nerve that carries signals from the brainstem through organs in the neck, chest, and abdomen.

vasospasm: abnormal narrowing or constriction of arteries due to irritation by blood in the subarachnoid space.

ventricles: hollow areas in the center of the brain containing cerebrospinal fluid. There are two lateral ventricles on each side of the brain, one third ventricle, and one fourth ventricle.

ventricular drain: a catheter placed in the ventricle of the brain to drain excess cerebrospinal fluid.

ventriculoperitoneal (VP) shunt: a tube placed in the ventricle of the brain to drain excess cerebrospinal fluid into the abdomen.

vertebra (plural vertebrae): one of 33 bones that form the spinal column, they are divided into 7 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 4 coccygeal. Only the top 24 bones are moveable.

vertebral body compression fracture (VCF): a break in the vertebral body of the spine that causes it to collapse and produce a wedge-shaped deformity.

vertebroplasty: a minimally invasive proce­dure used to treat vertebral compression fractures by injecting bone cement into the vertebral body; similar to kyphoplasty but does not restore vertebral height.

vertigo: dizziness.

video EEG monitoring: simultaneous monitoring of a patient’s behavior with a video camera and the patient’s brain activity by EEG.

weakness: a lack or reduction of strength in one or more muscles.

whiplash: an injury to the ligaments and muscles of the neck resulting from rapid acceleration or deceleration (as in an auto accident).

X-ray: electromagnetic radiation used in diagnostic imaging to view shadows of tissue density in the body, also called roentgenogram.