Mark Hornyak, MD

Glossary of Commonly Used Neurological Terms

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-A-

Acromegaly: a hormonal disorder that develops when your pituitary gland produces too much growth hormone during adulthood. When this happens, your bones increase in size, including those of your hands, feet and face
Adenoma: A benign tumor formed of glandular tissue.
Allograft: A graft of bone or tissue from an individual of the same species. Allografts are usually obtained from cadavers.
Allopathic medicine: refers to science-based, modern medicine. Practitioners are trained at accredited medical schools and are given the title, MD, Medical Doctor.
Ambulatory: 1. Able to walk. 2. Referring to a procedure that is performed without admission to a hospital (outpatient) where the patient returns home the same day as the procedure. Also a called same-day surgery.
Aneurysm: An abnormal bulging or stretching of a weakened wall of a blood vessel.
Angiography (arteriography): Imaging of blood vessels using injected contrast material (dye) to better visualize the vessels. A formal angiogram (also known as digital subtraction angiogram, DSA) is an invasive procedure, while angiograms using MRI or CT (MRA and CTA, respectively) are non-invasive, but may still require IV contrast dye.
Angioplasty: The reconstitution or opening of a blood vessel. Often used to restore blood flow to a constricted blood vessel that is not supplying sufficient blood to the heart or brain.
Annulus: The tough, fibrous outer ring of a spinal disk. Short for annulus fibrosus.
Anticoagulant: A medication that prevents coagulation of the blood. Classically warfarin (Coumadin) or heparin, but now includes many medications used to “thin the blood.”
Aphasia: Difficulty with language, or the loss of use of language, in reading, writing, or speaking. This failure to understand language is often due to specific lesions in the brain like a stroke or tumor.
Arachnoid membrane: The middle of three membranes that cover and protect the brain and spinal cord collectively called the meninges. The arachnoid membrane hold the cerebrospinal fluid (CSF) in which the brain and spinal cord are bathed.
Arachnoiditis: Inflammation of the arachnoid membrane, most commonly seen within the spinal cord around the spinal cord and cauda equina.
Arteriosclerosis: A thickening and calcification of the arterial wall with loss of elasticity and contractility.
Arteriovenous: Relating to both arteries and veins.
Arteriovenous malformation (AVM): A vascular malformation formed by a collection of blood vessels with one or more abnormal communications between arteries and veins, which may cause hemorrhage or seizures. They are most commonly found in the brain, but can be found in the spinal cord.
Arthrodesis: The surgical procedure which results in fixation or fusion of a joint.
Astrocytoma: A tumor within the substance of the brain or spinal cord derived from of astrocytes, a common cell found in the brain. They are often classified from grade I (slow-growing) to grade IV (rapidly growing and malignant).
Arthroplasty: replacement of a natural joint with an artificial construct
Ataxia: The loss of muscular coordination in the legs leading to difficulty walking
Atherosclerosis: Arteriosclerosis (see above) characterized by irregularly distributed fatty deposits in the arteries
Atrophy: Wasting and shrinking of the tissues of a body part.
Audiometry: the science of measuring hearing acuity for variations in sound intensity and pitch and for tonal purity, involving thresholds and differing frequencies. Simply, a hearing test.
Autograft: A graft of bone or tissue obtained from a patient for transplantation elsewhere on the same patient.
Axial plane: an imaginary plane that divides the body into superior and inferior parts. It is perpendicular to the coronal plane and sagittal plane; also called the transverse plane.

-B-

Benign essential tremor: a nervous system (neurological) disorder that causes involuntary and rhythmic shaking. It can affect almost any part of your body, but the trembling occurs most often in your hands — especially when you do simple tasks, such as drinking from a glass or tying shoelaces
Benign intracranial hypertension: Raised intracranial pressure, usually causing headache and occasionally papilledema without clear underlying structural abnormality. Formerly called pseudotumor cerebri.
Biopsy: The removal of a small portion of tissue, usually for the purpose of pathological examination in order to establish a definitive diagnosis.
Blepharospasm: A disorder in which the muscles of the eyelids (orbiculares oculi) do not function properly, and that includes intermittent and involuntary contractions or spasms of the muscles around the eyes.
Bone graft: Small piece(s) of extra bone that act as the "cement" for fusing vertebrae together.
Brachial plexus: A network of nerves in the neck, passing from the neck (cervical spine), under the collarbone, and into the armpit on their way to the arm. These nerves originate from the 5th, 6th, 7th and 8th cervical spinal nerves and the first 2 thoracic spinal nerves and form the major nerves going into the arm.
Bradykinesia: Slowness in movement.
Brainstem: The part of the brain residing within the back of the skull which connects to the spinal cord; the brainstem controls most vital functions.
Brown-Sequard's syndrome: The loss of sensation of touch, position, and movement on the same side of a spinal cord lesion, with loss of pain sensation on the opposite side. The syndrome is caused by an injury limited to one side of the spinal cord.

-C-

Carcinoma: Cancer; a malignant growth of epithelial or glandular cells.
Carotid artery: The large arteries on either side of the front of the neck that supply most of the blood to the brain.
Carotid cavernous fistula (CCF): An abnormal communication between the internal or external portions of the carotid arteries and the cavernous sinus.
Carotid sinus: Slight dilatation on the common carotid artery as it branches into the internal and external carotid arteries in the neck. It contains nerve cells sensitive to blood pressure; stimulation can cause slowing of the heart, vasodilatation, and a fall in blood pressure.
Catheter: A small, flexible tube placed into the body. It can be used to inject medication into the body (like an intravenous catherter, aka i.v.) or drain fluid (like a catheter in the bladder, a Foley catheter).
Cauda equina: The bundle of long spinal nerve roots arising from the end of the spinal cord and filling the lower part of the spinal canal (from approximately the thoracolumbar junction down). These long nerves resemble a horse's tail (cauda equine in Latin).
Cauda equine syndrome (CES): A condition that occurs when the cauda equina is damaged. Signs and symptoms include low back pain, pain that radiates down the legs, numbness of the legs and around the anus, and loss of bowel or bladder control.
Cavernous malformation (cav mal): A rare type of vascular malformation that can present with hemorrhage or seizure. It is small and resembles a black raspberry. They typically occur in the brain, but can also be found in the spinal cord. It is also called cavernoma or cavernous hemangioma.
Central nervous system (CNS): The brain and the spinal cord.
Cerebellum: The lower part of the brain, which is beneath the posterior portion of the cerebrum and regulates unconscious coordination of movement.
Cerebrospinal fluid (CSF): A clear, salty fluid that circulates around the brain and spinal cord.
Cerebrum: The principal portion of the brain, which occupies the major portion of the interior of the skull and controls conscious movement, sensation, and thought. It is separated into lobes and into the right and left hemispheres.
Cervical spine: The upper spine or neck; the cervical spine is made up of seven vertebrae.
Chemotherapy: a drug treatment that uses powerful chemicals to kill fast-growing cells in your body. Chemotherapy is most often used to treat cancer, since cancer cells grow and multiply much more quickly than most cells in the body. Many different chemotherapy drugs are available.
Chiari malformation: The downward displacement of part of the cerebellum or brainstem below the foramen magnum. It is often an asymptomatic, incidental finding on imaging studies, but may also cause headache, syringomyelia, or other symptoms.
Chiropractics: a pseudoscientific, complementary and alternative medicine that is concerned with the diagnosis and treatment of mechanical disorders of the musculoskeletal system, especially the spine.
Chorea: A movement disorder, characterized by irregular, spasmodic involuntary movements of the limbs or facial muscles.
Choroid plexus: A vascular structure in the fluid-filled ventricles of the brain that produces cerebrospinal fluid.
Coccyx: The small bone at the end of the spinal column, formed by the fusion of four rudimentary vertebrae. It is commonly called the "tail bone".
Coma: A state of unconsciousness from which one cannot be roused.
Computerized tomography (CT) scan: see CT scan
Concussion: A disruption, usually temporary, of neurological function resulting from a blow or violent shaking. Also called mild closed head injury.
Contrast medium (dye): Any material employed to delineate or define a structure during a radiologic procedure.
Coronal plane: is any vertical plane that divides the body into ventral and dorsal (belly and back) sections; also called the frontal plane.
Coronal suture: The line of junction of the frontal bones and the parietal bones of the skull. It runs from in front of one ear across the top of the skull to in front of the opposite ear.
Corpectomy: Removal of the body of a vertebra. The body is the solid bony mass, almost cylindrical in appearance, that forms the front part of each vertebra and bears the weight of the upper body.
Corpus callosum: The white-matter tract connecting the left and right hemispheres of the brain.
Cortex: The external layer of gray matter covering the hemispheres of the cerebrum and cerebellum.
Cranial nerve: One of twelve paired sets of peripheral nerves that arise directly from the brain and predominantly innervate the head and face including the special senses of smell, sight, hearing and taste.
Craniectomy: Surgical removal of a portion of the skull without replacement of the bone.
Craniopharyngioma: A congenital tumor arising from the embryonic duct between the brain and pharynx.
Cranioplasty: The operative repair of a defect of the skull.
Craniosynostosis: Premature closure of cranial sutures, limiting or distorting the growth of the skull.
Craniotomy: Surgical opening of the skull, usually by creating a flap of bone that is replaced at the completion of the procedure.
Cranium: The part of the skull that holds the brain.
CT scan (computed tomography scan): A diagnostic imaging technique that rapidly x-rays the body in cross-sections, or slices. A computer pieces together the data to create a three-dimensional images of the area studied.
Cushing disease: Cushing syndrome that is caused by over production of adrenocorticotropic hormone (ACTH) by a tumor of the pituitary gland.
Cushing syndrome: A condition that occurs from exposure to high levels of corticosteroids for a long time. The most common cause is the use of steroid drugs, but it can also occur from overproduction of cortisol by the adrenal glands. Signs are a fatty hump between the shoulders, a rounded face, purple stretch marks, high blood pressure, and high blood sugar. Treatment options include reducing steroid use, surgery, radiation, and medication, depending on the cause.

-D-

Diphenylhydantoin (DPH): Dilantin; a medication used to control seizures.
Diplopia: Double vision.
Disc: The intervertebral disc is a round, cartilaginous cushion found between the bony vertebrae of the spinal column. It, along with the posterior ligaments and joints, provides stability to the junction of two vertebral segments. It consists of two parts- the outer annulus fibrosus and the inner nucleus pulposus. A portion of the disc may migrate beyond the vertebral body and compress the nearby nerve root, causing pain.
Disc degeneration (also called degenerative disc disease (DDD)): A flattening or "wear and tear" of the disc. It can be accompanied by local swelling, and may result in pain.
Dome: The round balloon-like portion of an aneurysm that usually forms above a smaller portion called the neck of the aneurysm.
Doppler: A non-invasive study that uses sound waves to show the flow in a blood vessel and can be used to determine the degree of narrowing (percent stenosis) of the vessel. A wand is placed on the skin over the vessel to be imaged. This study has no risks and is not painful.
Dura mater: The tough fibrous outer membrane that covers the brain and spinal cord. It is one of three layers of coverings of the brain and spinal cord, the meningies.
Dysesthesia: A condition in which a disagreeable sensation is produced by ordinary touch, temperature, or movement.
Dysphagia: Difficulty swallowing. It may be caused by impairment of the nerves that coordinate swallowing or blockage of the swallowing pathways.
Dysphasia: Difficulty in the use of language without mental impairment due to a brain lesion.
Dystonias: A group of movement disorders that vary in their symptoms, causes, progression, and treatments. This group of neurological conditions is generally characterized by involuntary muscle contractions that force the body into abnormal, sometimes painful, movements and positions (postures).

-E-

Edema: An excessive accumulation of fluid in cells, tissues, or body cavities. Often characterized by swelling.
EDSI: see epidural steroid injection
Electroencephalography (EEG): The study of the electrical currents caused by brain actions. It is carried out by applying electrodes to the scalp, and the record made is called an electroencephalogram. It is most commonly performed to evaluate for seizure or other abnormal electrical activity of the brain.
Electromyography (EMG): A method of recording the electrical currents generated in a muscle during rest and contraction. It is carried out by placing needle-like electrodes into the muscles of the body being studied. It is most commonly performed to evaluate for diseases of the muscles or peripheral nerves, and is often performed with nerve conduction studies.
Encephalocele: The herniation of a portion of the brain and its meninges through a defect in the skull.
Endarterectomy: The removal of fatty or cholesterol plaques and calcified deposits from the internal wall of an artery.
Endocrinology: The field of medicine concenred with the endocrine system. This is the system of glands that secrete hormones.
Endoscope: A thin, telescope-like instrument. Typically, a video camera attaches to the endoscope allowing display of those images on a monitor. The endoscope and specially-designed surgical tools enable a surgeon to operate in natural body cavities that could not otherwise be reached without extensive tissue disruption.
Endovascular: referring to a process or procedure occurring inside a blood vessel. Commonly applied to a minimally invasive catheter-based approach for the treatment of vascular lesions like aneurysms and AVMs.
Endotracheal: inside the trachea (the windpipe); typically referring to a tube placed within the trachea to allow for mechanically-supported breathing.
ENT: see otolaryngology
Ependyma: The membrane that lines the inner surface of the cerebral ventricles of the brain and central canal of the spinal cord.
Ependymoma: A growth in the brain or spinal cord arising from ependymal tissue.
Epidural (extradural): The anatomical space immediately outside the dura mater and also immediately inside the skull or under the bone of the spine.
Epidural hematoma: A blood clot between the dura mater and the inside of the skull or spine.
Epidural steroid injection: a procedure in which a small dose of steroid medication is injected into the epidural space of the spine. It is often performed to reduce pain caused by radiculopathy. It is most commonly performed in the lumbar spine, but can be applied to the cervical spine as well. It is typically performed by a pain specialist. Also called an EDSI.
Epilepsy: A disorder characterized by abnormal electrical discharges in the brain, causing abnormal sensation, movement or level of consciousness known as a seizure.

-F-

Facet: A small, smooth-surfaced end of a bony projection that functions as part of a joint.
Facet block: a procedure in which a local anesthetic (numbing) medication is injected adjacent to a spinal facet joint in an effort to reduce pain that is caused by arthritis of the joint.
Facet joint: Each of four joints formed above, below, and on either side of a vertebra. The lower bony projection of one vertebra meets the upper projections of the vertebra below it, forming facet joints. It is also known as the zygopophyseal joint.
Facetectomy: Surgical removal of one of the facets; excision of a facet joint.
Falx cerebri: An extension of dura the lies between the right and left hemispheres of the brain.
Fluorescence: the emission of light by a substance that has absorbed light or other electromagnetic radiation. It can be used to guide surgeons using sophisticated imaging devices.
Fluoroscope: an imaging device that provides real-time x-ray images on a monitor. It is often used to guide instruments during many types of procedures.
Fontanelle: Normal openings in the skull of infants. The largest of these is the anterior fontanelle, the "soft spot" in the middle of the head.
Foramen: A hole or opening that acts as a passageway for nerves or blood vessels.
Foraminotomy: Surgical enlargement of the foramen/foramina.
Fractionated therapy: Radiation that is given in multiple lower-dose treatments rather than in a single session.
Fusiform aneurysm: A spindle-shaped enlargement of the blood vessel.

-G-

Gadolinium: 1. the chemical element with the symbol Gd and the atomic number 64. 2. A contrast medium containing the element gadolinium used to improve the quality of MRI scans. It is administerd intravenously (i.v.) and is often used to delinate tumors in the body.
Galactorrhea: the occurrence of a milk-like discharge from the nipple that is unrelated to the normal milk production of breast feeding.
Gamma Knife: Trade name of a specific brand of equipment that precisely delivers a concentrated dose of radiation to a predetermined target using gamma rays.
Glasgow coma scale (GCS): The most widely used system of classifying the severity of head injuries or other neurologic diseases.
Glia (glial cells): The major support cells of the brain. These cells are involved in the nutrition and maintenance of the nerve cells.
Glioma: A tumor formed by glial cells.
Glioblastoma (GBM): A rapidly growing malignant brain tumor. It is composed of primitive glial cells, mainly arising from astrocytes.
Globus pallidus: Part of the basal ganglia, which are distinct clusters of brain cells that lie deep in the brain and function to control movement
Greater occipital nerve: A branch of the second cervical spinal nerve that innervates the middle portion of the occipital area (at the back of the skull) of the scalp.

-H-

Hard cervical collar: a medical brace worn around the neck to provide support the cervical spine
Hemangioma: An aggregation of multiple dilated blood vessels.
Hematoma: A blood clot.
Hemianopia: The loss of vision of one-half of the visual field.
Hemiplegia: The paralysis of one side of the body.
Hemorrhage: Bleeding due to the escape of blood from a blood vessel.
Herniated nucleus pulposus (HNP): The extrusion of the central portion (nucleus) of an intervertebral disc through the outer cartilaginous ring (annulus). The herniated portion can compress the spinal cord or nerves in or exiting the spinal canal.
Hormone: Chemicals that are secreted by one organ or gland that effect the actions of a different orgen or system, typically through distribution in the blood stream. Examples include thyroid hormone, groeth hormone, and insulin.
Hydrocephalus: A condition marked by abnormal and excessive accumulation of cerebrospinal fluid in the cerebral ventricles. This dilates the ventricles and causes pressure on the surrounding brain tissue and may raise intracranial pressure.
Hydromyelia: Expansion of the spinal cord due to increased size of the central canal of the cord, which is filled with cerebrospinal fluid.
Hyperesthesia: Excessive sensibility to touch, pain, or other stimuli.
Hypertension: High blood pressure.
Hypophysectomy: Surgical removal of the hypophysis (pituitary gland).
Hypophysis: the pituitary gland. The master endocrine gland of the body. Under control of the brain (hypothalamus), regulates the function of many hormones in the human including thyroid hormone, cortisol, growth hormone, and sex hormones.
Hypothalamus: A collection of specialized nerve cells at the base of the brain that controls the anterior and posterior pituitary secretions, and is involved in other basic regulatory functions such as temperature control and attention.

-I-

Ictal: Related to a seizure
Image-guided surgery: a surgical procedure performed with the use of advanced imaging and tacking technologies that allows the surgical team to precisely guide instruments in real time.
Immunotherapy: a type of cancer treatment that helps the immune system fight cancer. The immune system helps your body fight infections and other diseases. It is made up of white blood cells and organs and tissues of the lymph system. Immunotherapy is a type of biological therapy.
Inpatient: referring to a procedure or medical encounter performed within a hospital and requiring admission to the hospital.
Instrumentation: Metal supports sometimes used in spinal fusions to help steady the spine while it fuses. Common types of support include plates, rods, screws, and cages.
Intra-arterial: Delivered into an artery (as opposed to intravenous, which is delivered into a vein).
Intracerebral hematoma (ICH): A blood clot within the substance of the brain.
Intracranial pressure (ICP): The overall pressure inside the skull.
Intravenous: Delivered into a vein.
Intrathecal: Within the dura mater membrane that surrounds the spinal canal.
Internal fixation: The surgical insertion of instrumentation into bone to stabilize the separate fragments.
Ischemia: Inadequate circulation of blood, generally due to a blockage of an artery.

-J-

Juvenile pilocytic astrocytoma: A slow-growing brain tumor that develops—usually in children and adolescents—from cells called astrocytes.
Jugular veins: The major veins on each side of the neck that drain blood from the head towards the heart.

-K-

Kyphoplasty: An image-guided procedure in which a balloon is inserted into a fractured vertebra via a needle to create a cavity. A special bone cement is injected into the cavity to stabilize the bone, and treat pain. Kyphoplasty is most often used to treat spinal compression fractures.
Kyphosis: The forward curvature of the spine. It is the normal curvature of the thoracic spine, but can be abnormal in its extent. Is considered a deformity if found in the cervical or lumbar spine.

-L-

Lamina: The posterior portion of bone that extends from the pedicle and curves around to joint the spinous process in the midline completing the vertebral arch on the right and left sides.
Laminectomy: Removal of one or more entire lamina. Used to decompress the nerves within the spinal canal or to surgically access the spinal canal other.
Laminotomy: A surgical procedure where part of the lamina of a vertebra is removed for access to spinal canal. It is often used to access a herniated disc.
Leptomeninges: The two innermost, thin layers of fine tissue covering the brain and spinal cord (the pia mater and arachnoid membrane).
Leptomeningitis: Inflammation of the membranes covering the brain and spinal cord.
Lipoma: A benign fatty tumor, usually composed of mature fat cells.
Lordosis: Curvature of the spine with the convexity forward. It is the normal curvature of the cervical and lumbar spine.
Lumbar drain: A device (usually a long, thin flexible tube) inserted through the skin into the cerebrospinal fluid space of the lower back; provides a method of draining cerebrospinal fluid.
Lumbar puncture (spinal tap): A diagnostic test in which a sample of cerebrospinal fluid is removed from an area just below the end of the spinal cord through a thin needle inserted into the spinal canal through the skin of the back. It is commonly used to detect abnormalities in the cerebrospinal fluid, like blood or infection, and can also be used to measure pressure or deliver medication.
Lumbar spine: Lower spine, lower back. Usually consists of the five vertebrae between the thoracic spine and the sacrum.
Lumbosacral orthotic: a medical back brace worn about the waist that supports the lower back. Also called an LSO.
LSO: see lumbosacral orthotic

-M-

Magnetic resonance angiography (MRA): A non-invasive study conducted in a magnetic resonance imager (MRI). It provides images of the arteries in the head and neck. Contrast material is not always needed.
Magnetic resonance imaging (MRI): Diagnostic test that uses powerful magnets and radio waves to produce three dimensional images of the body part being studied. It uses no x-rays, but intravenous (i.v.) contrast (called gadolinium, Gadavist) may be used.
Median nerve: The nerve formed from the brachial plexus that supplies muscles in the anterior forearm and thumb as well as sensation of the hand. It may be compressed or trapped at the wrist in carpal tunnel syndrome.
Medulloblastoma: A tumor composed of medulloblasts, which are cells that develop in the roof of the fourth ventricle (medullary velum).
Meninges: The three membranes—the dura mater, arachnoid mater, and pia mater—covering the spinal cord and brain.
Meningioma: A tumor arising from the meninges of the brain or spinal cord. The vast majority are benign. The primary treatment is most often surgical resection when possible.
Meningitis: An inflammation or infection of the meninges.
Meningocele: A protrusion of the meninges of the spinal cord through a defect in the spinal column.
Meningoencephalitis: An inflammation or infection of the brain and meninges.
Meningoencephalocele: A protrusion of both the meninges and brain tissue through a skull defect.
Metastasis: The spread of a cancer from one site, the primary site, to another, secondary, site in the body. Typically seen with cancerous tumors.
Minimally invasive: A surgical procedure carried out using advanced techniques and equipment resulting in less tissue injury than an alternative technique. Typically refers to a spine procedure where a small incision is made and specialized instrumentation is used through this incision.
Movement disorders: a group of nervous system (neurological) conditions that cause abnormal increased movements, which may be voluntary or involuntary. Movement disorders can also cause reduced or slow movements. Movement disorders are managed by neurologists.
MRI: see magnetic resonance imaging
Myelogram: An x-ray of the spinal canal following injection of a contrast material into the surrounding cerebrospinal fluid spaces via a lumbar puncture
Myelopathy: Any functional or pathologic disturbance in the spinal cord.
Myelomeningocele: A protrusion of the spinal cord and its coverings through a defect in the vertebral column.
Myopathy: Any disease of muscle.

-N-

Nerve root: The spinal nerve within and immediately outside of the spinal canal.
Neuralgia: An episodic pain extending along the course of one or more nerves.
Neurectomy: Excision of part of a nerve.
Neuritis: Inflammation of a nerve.
Neuroblastoma: A tumor of sympathetic nervous system origin, found mostly in infants and children.
Neurofibroma: A tumor of the peripheral nerves due to an abnormal collection of fibrous and insulating cells.
Neurofibromatosis: A familial condition characterized by developmental changes in the nervous system, muscles, and skin, marked by numerous tumors affecting these organ systems.
Neurology: the branch of medicine concerned with the study and medical treatment of disorders of the nervous system.
Neurolysis: Removal of scar or reactive tissue from a nerve or nerve root.
Neuroma: A tumor or abnormal growth largely made up of nerve fibers and connective tissue.
Neuropathy: Any functional or pathologic disturbance in the peripheral nervous system. Disorder may be localized secondary to lesion or generalized secondary to medical disorder.
Neurosurgery: is the medical specialty concerned with the prevention, diagnosis, surgical treatment, and rehabilitation of disorders which affect any portion of the nervous system including the brain, spinal cord, central and peripheral nervous system, and cerebrovascular system. Also known as neurological surgery. Click here for more information
Normal pressure hydrocephalus: a condition in which excess cerebrospinal fluid (CSF) occurs in the ventricles, and with normal intracranial pressure. As the fluid builds up, it causes the ventricles to enlarge stretching surrounding brain pathways and leading to neurological complications. The disease presents in a classic triad of symptoms, which are dementia, gait disturbance, and urinary incontinence
Nuclear medicine: a medical specialty involving the application of radioactive substances in the diagnosis and treatment of disease.
Nucleus pulposus: The soft center of a spinal disc.
Nystagmus: Involuntary rapid movement of the eyes in the horizontal, vertical, or rotary planes of the eyeball.

-O-

Occiput: The back part of the head.
Oligodendroglia: Non-nerve cells (see glia) forming part of the supporting structure of the central nervous system.
Oligodendroglioma: A brain tumor derived from the oligodendroglia.
Oncology: the branch of medicine that deals with the prevention, diagnosis, and treatment of cancer. A medical professional who practices oncology is an oncologist.
Orbital: Related to the bony eye socket and surrounding area.
Orthotic: an artificial support or brace for the limbs or spine
Osteoma: A benign tumor of bone.
Osteomyelitis: Inflammation of bone due to infection, which may be localized or generalized.
Osteopathic medicine: a type of alternative medicine that emphasizes physical manipulation of muscle tissue and bones. Practitioners of osteopathy are referred to as osteopaths and are given the title DO, Doctor of Osteopathy.
Osteophyte: An abnormal growth of bone typically due to degenerative and reactive changes in the bone related to arthritis. Commonly called a “bone spur.”
Osteophytectomy: Surgical removal of an osteophyte. Osteophytes may develop on the edges of the vertebral bodies, causing pressure on the spinal cord or nerve roots.
Otolaryngology: a medical specialty which is focused on the ears, nose, and throat. It is also called head and neck surgery because specialists are trained in both medicine and surgery. An otolaryngologist is often called an ear, nose, and throat doctor, or an ENT for short.
Outpatient: referring to a procedure or medical visit that is performed without requiring admission to a hospital.

-P-

Papilledema: Swelling of the optic nerve head in the back of the eye. It can be seen in the back of the retina during an eye examination.
Paraplegia: Paralysis of the lower part of the body including the legs.
Paresthesia: Numbness, tingling, or a "pins and needles" feeling.
Pars interarticularis: The area between the upper and lower articulating processes of a vertebrae.
Pedicle: One of the two short stems of bone that project outward from the body of each vertebra connecting with the lamina and creating the lateral walls of the spinal canal. The pedicle is often used as an access corridor for the vertebral body in procedures like kyphoplasty and in the placement of pedicle screw instrumentation.
Perimetry: see visual field testing.
Peripheral nervous system: The peripheral part of the nervous system external to the brain and spinal cord from their roots to their peripheral terminations. This includes the nerve roots and peripheral nerve.
PET scan: see positron emission tomography
Physician assistant: a licensed medical professional who is educated in general medicine and trained to practice medicine. Physician assistants may practice autonomously and independent of physicians or collaboratively with physicians.
Pituitary gland: see hypophysis.
Polyneuritis: Inflammation of two or more nerves simultaneously.
Positron emission tomography: an imaging technique that uses radioactive substances to visualize and measure metabolic processes in the body. PET is mainly used in the area of medical imaging for detecting or measuring changes in physiological activities like metabolism, blood flow, regional chemical composition, and absorption, and therefore, also called a functional imaging technique.
Posterior fossa: The volume in the back of the skull in which the cerebellum and brainstem are located.
Pre-ictal: Preceding a seizure
Proprioception: Sensation concerning movements of joints and position of the body in space.
Pseudoarthrosis: Failure of fusion to achieve proper union of vertebrae resulting in continues motion of the segment.
Pseudomeningocele: A collection of cerebrospinal fluid outside of the spinal canal that is due to a dural leak after a spine procedure; it is not a congenital disorder.
Pseudotumor cerebri: see benign intracranial hypertension.
Pupil: The window in the eye through which light enters. It enlarges in dim light and decreases in size in bright light and appears black.

-Q-

Quadriplegia: The paralysis of all four

-R-

Radiation oncologist: A medical doctor who has received advanced training in the treatment of persons receiving x-ray treatment for an illness. Radiation therapy is typically used to treat cancer and some benign tumors.
Radiation physicist: A person having a PhD degree who is trained in the science dealing with the properties, changes, and interactions of continuous energy. This person will typically assist the radiation oncologist in the safe delivery of therapeutic radiation.
Radiculitis: Inflammation of a spinal nerve root, typically in the absence of compressive pathology (pinched nerve). Accompanied by pain and hyperesthesia as seen with radiculopathy.
Radiculopathy: A condition caused by a pinched nerve in the spine (the upper or cervical spine, the thoracic or middle spine, or the lumbar or lower spine). It results in pain in the distribution of the affected nerve, numbness, tingling, and/or weakness.
Radiologist: A medical doctor who has received specialized training in interpreting x-rays, CTs, MRIs, and performing angiography.
Radiotherapy: Treatment of a lesion with radiation
Reflex sympathetic dystrophy: A condition characterized by burning pain, abnormal sensitivity to sensory stimuli, poor circulation, and changes in the skin, muscle, bone, and joints.
Revascularization: Reestablishment of blood supply to a part.
Rhizolysis: a procedure in which a nerve or small bundle of sensory nerves are intentionally damaged. It is typically performed to prevent the nerve from sending pain signals, thus relieving pain.

-S-

Saccular aneurysm: A balloon-like outpouching of an artery. Also called a Berry aneurysm.
Sagittal plane: an anatomical plane which divides the body into right and left parts.[1] The plane may be in the center of the body and split it into two halves (mid-sagittal) or away from the midline and split it into unequal parts (para-sagittal); also called the longitudinal plane.
Sagittal suture: The line of junction of the parietal bones of the skull. It is in the midline of the top of the head, running from the front to the back.
Schwannoma: a usually benign nerve sheath tumor composed of Schwann cells, which normally produce the insulating myelin sheath covering peripheral nerves. They can occur within the cranium, in the spine, and along the course of peripheral nerve.
Sciatic nerve: The largest nerve in the body. It extends from the sacral plexus, emerges from the pelvis, and travels deep within the buttocks. It then descends down the back of the thigh to the back of the knee, at which point it divides into the common peroneal and tibial nerves. The sciatic nerve supplies sensation to the back of the thigh, outer side of the leg, and essentially the whole foot.
Seizure: Abnormal electrical activity in the brain that results in an abnormal outward consequence such as involuntary movement of a limb or unconsciousness.
Shunt: a tube that diverts body fluid from one body cavity or vessel to another.
Single-photon emission computed tomography: a nuclear medicine tomographic imaging technique using gamma rays. It is very similar to conventional nuclear medicine planar imaging using a gamma camera (that is, scintigraphy), but is able to provide true 3D information. This information is typically presented as cross-sectional slices through the patient, but can be freely reformatted or manipulated as required.
Soft cervical collar: a soft brace worn about the neck to provide comfort for patients with neck pain. It is not an orthotic and does not provide significant immobilization.
Spasmodic torticollis: Also known as cervical dystonia, is a form of dystonia characterized by intermittent spasms of the neck muscles resulting in involuntary rotation and tilting of the head. These movements are frequently painful.
SPECT scan: see single-photon emission computed tomography
Spina bifida: A congenital defect of the spine marked by the absence of a portion of the spine.
Spinal fusion: Operative method of strengthening and limiting motion of the spinal column by causing the individual vertebra of the spinal column to grow together into one strong bone. It can be performed with a variety of instrumentation and bone grafts or with bone grafts alone.
Spinal instability: Occurs when damage to the bone or ligamentous structures causes the spine to be unable to carry out its supporting function. It may result from trauma or degenerative processes and is often seen as an abnormal alignment of the spine.
Spinal tap: See lumbar puncture
Spinous process: The bony prominence projecting backward from a vertebra that can be felt under the skin of the back.
Spondylolisthesis: Forward displacement or slippage (subluxation) of one vertebra over another.
Spondylosis: Degenerative bone changes in the spine usually most marked at the vertebral joints with bony spur formation. It can be considered arthritis of the spine.
Stenosis: Narrowing of the openings of the foramen and/or the spinal canal; narrowing of a blood vessel.
Stent: An endovascular prosthetic device, usually an open mesh cylinder, placed within a blood vessel to provide the support to keep that vessel open.
Stereotactic radiosurgery: a non-surgical radiation therapy used to treat functional abnormalities and small tumors of the brain. It delivers precisely-targeted radiation in fewer high-dose treatments than traditional therapy, which can help preserve healthy tissue.
Stereotactic surgery: Surgical technique whereby the exact location of a target is calculated three-dimensionally.
Stroke: a sudden interruption in the blood supply of the brain. Most strokes are caused by an abrupt blockage of arteries leading to the brain (ischemic stroke). Other strokes are caused by bleeding into brain tissue when a blood vessel bursts (hemorrhagic stroke). Also called a cerebrovascular accident (CVA).
Subarachnoid: Located under the arachnoid membrane and above the pia mater.
Subarachnoid hemorrhage: Blood in, or bleeding into, the space under the arachnoid membrane, most commonly from trauma or from rupture of an aneurysm.
Subdural: Located below the dura mater and above the arachnoid meninges.
Subdural hematoma: A collection of blood (clot) trapped under the dura matter, the outermost membrane surrounding the brain and spinal cord.
Syringomyelia (syrinx): A fluid-filled cavity in the spinal cord, often occurring with Chiari malformation.

-T-

Teratoma: Tumor or growth made up of several different types of tissue (fat, bone, muscle, skin).
Thalamus: Brain cells that lie in the upper part of the brainstem.
Thoracolumbosacral orthotic: a medical back brace worn around the chest and abdomen providing suppost to the mid (thoracic) and lower (lumbar) spine.
Thrombolytic agent: A drug used to break up clotted blood. Also known as a “clot-busting" drug; such agents may be administered into veins or arteries.
Thrombus: A blood clot attached to the wall of an artery.
Tic douloureux: See trigeminal neuralgia.
TLSO: see thoracolumbosacral orthotic
Torticollis: The spasmodic contraction of neck muscles drawing the head to one side with the chin pointing to the other side.
Transsphenoidal approach: Operative method of reaching the pituitary gland or anterior skull base by traversing through the nose and paranasal sinuses.
Transverse process: The wing of bone on either side of each vertebral arch where the pedicle meets the lamina.
Tremor: A neurologic movement disorder characterized by involuntary fine rhythmic tremor of a body part or parts, primarily the hands and arms (upper limbs). In many affected individuals, upper limb tremor may occur as an isolated finding. However, in others, tremor may gradually involve other anatomic regions, such as the head, voice, tongue, or roof of the mouth (palate), leading to difficulties articulating speech (dysarthria). Less commonly, tremor may affect muscles of the trunk or legs.
Trigeminal nerve: The fifth cranial nerve and the largest, it is primarily sensory except for a small motor branch that supplies the muscles for chewing. The branches of the trigeminal nerve provide sensation to the eye and forehead, midface, and upper and lower jaw.
Trigeminal neuralgia: Episodic shoot pain in the face. Pain may be so severe that it causes an involuntary grimace or "tic" (Formerly called tic douloureux).

-U-

Ulnar nerve: one of the arm's major nerves and is part of the brachial plexus nerve system. It gets its name from its location near the ulna bone, a bone in the forearm on the side of the pinkie finger. The ulnar nerve starts outside the neck and travels through the shoulder down the arm into the wrist and fingers. It is commonly called the “funny bone nerve” as its superficial course near the elbow allows it to be struck, causing electric shock-like sensation to radiate into the hand.
Ultrasound: The use of high-frequency sound to create images of internal body structures.

-V-

Vascular: Related to blood vessels. Cerebrovascular disorders are those that affect the blood vessels in the brain.
Vasodilatation: An increase in the diameter of blood vessels.
Vasopressin: A hormone secreted by the hypothalamus and stored in the posterior pituitary, which raises blood pressure and increases reabsorption of water by the kidneys.
Vasopressor: An agent which constricts the arteries and raises blood pressure.
Vasospasm: A state of spasm that tightens and narrows blood vessels around the brain. It can be seen after an aneurysm ruptures causing a subarachnoid hemorrhage as the blood that has escaped the artery irritates the arterial wall. It can be severe enough to cause life-threatening ischemia more than a week after the initial hemorrhage.
Venous: Related to veins.
Ventricle: The cavities or chambers within the brain that contain the cerebrospinal fluid. There are two lateral ventricles, a midline third, and a fourth ventricle in the back of the cranium.
Ventricular drainage: Use of a small tube in the ventricles, inserted via ventriculostomy, It is used to drain cerebrospinal fluid, usually when pressure is increased.
Ventriculitis: Inflammation and/or infection of the ventricles.
Ventriculostomy: An opening into the ventricles of the brain, such as by inserting a small, thin, hollow catheter through a small opening in the skull and through the substance of the brain.
Ventriculo-atrial: Describing a cerebrospinal fluid shunt from one of the ventricles in the brain to the right atrium of the heart.
Ventriculogram: An x-ray study of the ventricles.
Ventriculomegaly: Enlarged cerebral ventricles.
Ventriculo-pleural: Describing a cerebrospinal fluid shunt from one of the ventricles of the brain to the pleural cavity in the chest.
Vermis: The middle part of the cerebellum between the two cerebellar hemispheres.
Vertebra: Any of the 33 bones of the spinal column.
Vertebral artery: the large artery on either side of the back of the neck that supplies blood to the back of the brain. The arteries run through a foramena in the vertebra of the neck and then join to form a single artery once they have entered the cranium.
Vertebroplasty: An image-guided procedure in which a special bone cement is injected into a fractured vertebra to stabilize the bone and relieve pain. Vertebroplasty is often used to treat spinal compression fractures.
Vertigo: An abnormal sensation of spinning or movement of one's self or the environment.
Visual field: the entire area that can be seen when an eye is fixed straight at a point
Visual field testing: testing of the peripheral vision. It may be performed by a practitioner or with a machine. Also called perimetry.

-W-

White matter: The part of the brain inside the cortex (the wrinkled gray matter). White matter consists of glial cells, nerves, and axons that transmit impulses.
WHO tumor grading: The standard established by the World Health Organization (WHO) to rate tumors.
    Grade I tumors are slow-growing, nonmalignant, and associated with long-term survival.
    Grade II tumors are relatively slow-growing but sometimes recur as higher grade tumors. They can be nonmalignant or malignant.
    Grade III tumors are malignant and often recur as higher grade tumors.
    Grade IV tumors reproduce rapidly and are very aggressive malignant tumors.

-X-

X-ray: 1. A type of electromagnetic radiation. 2. Application of x-rays to produce a film or picture of a bone or soft-tissue area of the body. X-rays are considered ionizing radiation that can be harmful if received in large doses.