Screen Readers Skip to Content
🖶 Print page

Definitions and Pronunciation of Medical Terminology

Published: 2009-01-11 - Updated: 2020-03-30
Author: Disabled World | Contact:
Peer-Reviewed Publication: N/A
Additional References: Glossary and Definitions Publications

Synopsis: A to Z list of brief definitions relating to basic medical, disability, and health condition terms, includes English pronunciation of various medical conditions and medications. Medical Terminology often uses words created using prefixes and suffixes in Latin and Ancient Greek. Greek prefixes go with Greek suffixes and Latin Prefixes with Latin Suffixes. Prefix: Added in front of the term to modify the word root by giving additional information about the location of an organ, the number of parts, or time involved.


Main Digest

This document provides an alphabetical glossary of definitions of medical terms including pronunciation of various diseases and health conditions.

Related Publications:

Medical terminology is language that is used to accurately describe the human body and associated components, conditions, processes and procedures in a science-based manner.

A medical dictionary is a lexicon for words used in medicine. In medical dictionaries, definitions should to the greatest extent possible be:

Image from page 208 of An illustrated encyclopedic medical dictionary. Being a dictionary of the technical terms used by writers on medicine and the collateral sciences, in the Latin, English, French and German languages (1890).
Image from page 208 of An illustrated encyclopedic medical dictionary. Being a dictionary of the technical terms used by writers on medicine and the collateral sciences, in the Latin, English, French and German languages (1890).

Basic Medical Terminology List

Medical Terminology

Medical Terminology often uses words created using prefixes and suffixes in Latin and Ancient Greek. Greek prefixes go with Greek suffixes and Latin Prefixes with Latin Suffixes.

Prefix: Added in front of the term to modify the word root by giving additional information about the location of an organ, the number of parts, or time involved. Examples of medical terminology prefixes include:

  • Brachi/o - Arm
  • Cardi/o - Heart
  • Cyt/o - Cell
  • Derm/a, derm/o, dermat/o - Skin
  • Encephal/o - Brain
  • Gastr/o - Stomach
  • Hemat/o - Blood
  • Hist/o, histi/o - Tissue
  • Intestin/o - Intestine
  • Lapar/o - Abdomen, loin or flank
  • My/o - Muscle
  • Neur/o - Nerve
  • Ocul/o - Eye
  • Ophthalm/o - Eyes
  • Or/o - Mouth
  • Ot/o - Ear
  • Pulmon/o - Lungs

Suffix: Attached to the end of a word root to add meaning such as condition, disease process, or procedure. Examples of medical terminology suffixes include:

  • A breaking down is -lysis
  • Blood terms end in -emia
  • Breathing terms end with -pnea
  • Inflammation is -itis
  • Pain terms end with -algia
  • Relating to disease is -opathy

Alphabetical Glossary and Definitions of Medical Terms



4-Amino-Pyridine (4-AP): An experimental drug that eases symptoms for some with MS, particularly if you are more Heat Sensitive. 4-AP is a Potassium Channel Blocker that improves Conduction of Nerve Impulses, through Axons with or without DeMyelination. Its use may cause Seizure, Convulsion, or Dizziness.

Abatement: A reduction in severity of symptoms.

Abiotic: Not related to living organisms.

Abortive: Cutting short the course of a disease.

Abrasion: Friction wearing away of the top layer of skin.

Abruption: A sudden breaking away or breaking off.

Accessory: Extra or supplementary to the main element.

Acetylcholine: An excitory Neuro-Transmitter that is produced and used by Cholinergic Neurons to communicate with each other.

ACTH: Abbreviation for AdrenoCorticoTrophic Hormone a Steroid produced by the Anterior Pituitary Gland, it stimulates the Adrenal Cortex to release several Hormones including Cortisol.

Acne: The commonly used name for pores clogged by sebum (also known as whiteheads and blackheads), pimples, nodules or cysts that can appear on the face, neck, shoulders, chest, back, upper arms and upper legs.

Acuity, Visual - Clarity of vision: Visual acuity is expressed as a fraction of normal vision. 20/400 means an Eye that sees at 20 feet what an average Eye sees at 400 feet.

Addiction: (say: uh-dik-shun) - This is a condition where you become dependent on, or can't do without, physical substances or an activity to the point that stopping it is very hard and causes severe physical and mental reactions. Substances you can become addicted to include tobacco, alcohol, and drugs (both illegal and prescription drugs). Activities that can be addicting include lying, stealing, and gambling. Addiction can be treated with counseling and, in some cases, medication.

Adolescence: (say: add-ul-ess-ence) - The period of life from puberty to adulthood when a young person "grows up."

Adrenal glands: (say: a-dree-nal) - A pair of small glands, each of which sits on of the kidneys. These glands produce hormones that help to control the body's heart rate, blood pressure, the way food gets used, and other functions. They make the hormone adrenaline, which the body releases in response to stress.

AIDS: (say: ayds) - This disease hurts the immune system, (the body's way of protecting itself), so that it becomes easy to get dangerous infections and cancers. It is caused by the HIV infection.

Albinism: (say: al-byn-is-em) - A group of conditions that cause a problem with your body's ability to make melanin, which is the pigment (color) of your skin, hair and eyes. This can make the skin and hair look very white.

Allergies: (say: al-ur-jee) - When someone has an allergic reaction to something, the body's immune system (which protects the body from outside substances), gives off a much bigger response than it normally would. The result is to have a reaction, such as sneezing or trouble breathing, to things that are usually not harmful, such as certain foods or animals.

Ambulatory: Ability to walk.

Amenorrhea: (say: uh-men-or-ee-uh) - When a woman does not have periods, either ever (after age 16) or they s as a result of: pregnancy, too much exercise, extreme obesity or not enough body fat, or emotional distress.

Amines: Are derived from the Amino Acid Tyrosine and are secreted from the Thyroid and the Adrenal Medulla.

Amino Acids: Chemical substances (building blocks of Protein) the body obtains from food. Essential Amino Acids (Only obtained from food)
Histidine, Isoleucine, Leucine, Lysine, Methionine, Phenylalanine, Threonine, Tryptophan and Valine - Non-Essential Amino Acids - (Body Can derive them) - Alanine, Argine, Asparagine, Aspartic Acid, Cysteine, Glutamic Acid, Glutamine, Glycine, Proline, Serine, Taurine and Tyrosine.

Analgesia: Loss of pain where pain would normally be evident without loss of consciousness.

Anesthesia: Loss of feeling (Pain and Touch Perception) over part or all of the body.

Analgesics: (say: ah-nuhl-jee-zicks) - Analgesics are meant to relieve pain. These pain relievers don't get rid of what causes your pain, rather they block the nerve pathways that send pain signals from the body part to the brain so that you don't hurt as much.

Anemia: (say: uh-nee-mee-uh) - When there are fewer red blood cells in the blood, it can cause health problems. This is measured by a decrease in what is called hemoglobin, which both provides the red color and moves oxygen through the body. There are many different types of anemia.

Anorexia nervosa: (say: an-or-eck-see-uh nur-vo-suh) - An eating disorder causes people to refuse to stay at a healthy body weight by not eating. People with anorexia have a fear of gaining weight and a picture of what their body looks like in their mind that is not what it really is.

Anoxia: A condition or state that exists, when there is not enough Oxygen for tissue Oxygenation.

Antibiotic: (say: an-ty-by-ah-tiks) - Antibiotics fight bacterial infections by killing bacteria or stopping it from growing. Antibiotics can help your body's immune system fight off infections. If you have ever had strep throat, your doctor probably gave you an antibiotic to take.

Antibodies: (say: an-ty-bod-eez) - Proteins produced by white blood cells to fight bacteria, viruses, and other foreign substances.

Anterior Horn: Nerve Ganglia in the Gray Matter of the Spinal Cord containing Motor Neurons. The Posterior Horn (top) contains Sensory Neurons, which directly command Skeletal Muscles, to perform quick or repetitive movements and are the final target of most Neural activity. Lesions in the Cerebrum, Basal Ganglia, Cerebellum, or Pyramidal Tracts affect their function. ex: Unstable gait, or In-coordinate fingers. Anterior Horn Cell (Anterior Horn Neuron) - A Motor Neuron in the Anterior Horn Gray Matter. These cells innervate Muscle Fibers directly to produce movement of body parts.

Anti-Bodies: Are complex Glyco-Proteins (Immuno-Globulins) having a destructive impact on specific Antigens (ie, Germs, Parasites, Bacteria, and other foreign substances) that stimulated their formation, conferring Immunity against exactly that Antigen. They are produced by Plasma Cells (B-Cells that have differentiated), in direct response to an Antigen's presence.

Antigen: A molecular protein or carbohydrate substance (Virus, Toxin, or Enzyme), which stimulates an "Immune Response". Any substance that triggers the Immune System to produce an AntiBody.

Antigen-Presenting Cell (APC): A specialized type of Leukocyte, bearing cell surface Class II MHC (Major Histocompatibility Complex) molecules. APCs process and present Antigens to an Inducer, T-Cell, or Helper T-Cell. Examples: Macrophage, Neutrophil, Dendrite, and B-Cell

Anti-Inflammatory Drugs: Over-the-counter and prescription medications (Steroids) that are sometimes recommended to decrease inflammation. Aspirin and Ibuprofen are types of over-the-counter anti-inflammatory medications.

Aphasia: Loss of Speech expression or comprehension.

Apoptosis: Biologically programmed cell death - self destruction (Cell Suicide).

Arteries: (say: ar-tuh-reez) - Thick-walled blood vessels that carry blood away from the heart to other parts of the body.

Asphyxiation: (say: as-fix-eeh-ay-shun) - Suffocation or smothering.

Aspiration: Inhaling food particles or fluids into the lungs. Asthma (say: az-muh) - When your airways are inflamed, causing you to wheeze, feel shortness of breath, cough and feel a tightness in your chest.

Asymmetry: Unequal or out of balance. Not the same on the two sides of the body.

Ataxia: The inability to maintain balance, while walking. The failure of muscular coordination, poorly coordinated gait or limb movements. Ataxia is seen as a reeling, wide-based Gait and is one of the most obvious signs of damage to the Cerebellum, or its connecting Neural Pathways.

Attention Deficit Disorder: (say: A-D-H-D) - A behavioral condition that makes it hard for people to pay attention and concentrate.

Atrophy: A loss of substance, it refers to the loss of bulk in a Muscle, Nerve, or an Organ that is shrunken (Atrophied), from less than normal usage or from previous damage.

Atrophy, Optic: Pallor and loss of Blood Vessels on the Optic Nerve Head, as seen through the Ophthalmoscope. This is caused by the loss of Myelin or of Optic Nerve Fibers and Blood Vessels in the Optic Nerve.

Autism: (say: ah-tiz-em) - Disorder in the brain that affects both verbal and nonverbal communication (speaking and non-speaking) skills.

AutoImmune Disease: A process in which the body's Immune System causes illness by attacking elements, such as particular cells or materials, that are normal and essential for health. The Immune System is the body's defense system against abnormal substances (such as Viruses or Bacteria) in the body - In AutoImmune disorders, the Immune System attacks substances that are needed by (versus harmful to) the body.

Autonomic Nervous System: Regulates In-Voluntary (UnConscious) body functions, such as the activity of the Cardiac Muscle; Smooth Muscles (ex: Stomach and in the Skin); controls the secretions of internal Glands (Hormones); and the functions of the Respiratory, Circulatory, Digestive, and Urogenital Systems. Its two divisions counter-act each other, in order to achieve the appropriate response:
The Sympathetic Division - accelerates the Heart beat, constricts and dilatates Blood Vessels, dilates the Bronchi and inhibits the Digestive System. It is most active under all conditions of Stress - it prepares the body for physical action (survival).

Axons: Are elongated Processes (Nerve Fibers) of Neurons. They enhance the speed of transmitting Nerve Impulses (Conduction) from one Neuron to another, due to the combined benefits of their large diameters, Nodes Of Ranvier, and Myelin wraps.

Axonal damage: (Wallerian Degeneration), loss, or Atrophy are the cause of permanent MS Disability. Axons have been simplistically compared to electric wires; however, Axons are the part of Neurons that actively generate electric current (Action Potential), while wires passively conduct current.
(Also See: MS Lesions & Axons and Disability)


B-Cell: A White Blood Cell (Lymphocyte) that makes Proteins known as Immuno-Globulins. A type of White Blood Cell that matures into AntiBody producing cells (Plasma Cells), when exposed to specific stimuli (Antigen).

Babinski's Sign: When the sole of the foot is scratched, the big toe goes up instead of down. This is an indication that there is a Lesion (Plaque) somewhere between the Motor Cortex, on the Opposite side of the Brain, and the Lower Spinal Cord Neuron (Anterior Horn Neuron). This is a hallmark sign of Pyramidal Tract Disease (Spasticity).

Baclofen (Lioresal): A prescription medication that relieves muscle Spasticity. Baclofen is an AntiSpasticity drug that interferes with the Spinal Cord activity that produces Increased Muscle Tone (Spasticity), in the Body's Smooth Muscles (ex: Legs, Arms, and Bladder). Baclofen is chemically related to the NeuroTransmitter, Gamma-AminoButyric Acid (GABA), and it decreases electrical activity of some Spinal Nerves, by blocking GABA's receptor sites. It inhibits Reflex Spinal Nerve Centers that initiate muscle contractions and its long-term use, leads to increased muscle weakness.

Basal Ganglia: Are a group of Functionally Related Nuclei, located bilaterally in the interior of the inferior aspect of the Cerebrum, the Mid-Brain and the DienCephalon. They are the Largest Nuclei of the Brain and play an important role in Planning and Coordinating Motor Movements and Posture. Exert their influence over the networks that link the Motor Cortex to other Cortical Areas. The Basal Ganglia behave as a variable filter ensuring smooth Muscle Movements.

Benign: An abnormal growth that is not life-threatening.

Blood-Brain Barrier: A semi-permeable cell layer of Endothelial Cells (interior walls) within Capillaries of the Central Nervous System (CNS). The Blood-Brain Barrier prevents large molecules, Immune Cells, all potentially damaging substances, and foreign organisms (e.g. Viruses), from passing out of the Bloodstream and into the CNS (Brain and Spinal Cord). A dysfunction in the Blood-Brain Barrier may underlie the disease process in MS.

Blood pressure: (say: blud presh-er) - As blood is pumped from your heart through your body, the blood exerts force or pressure against the blood vessel walls. Your blood pressure reading is a measure of this pressure. When that reading goes above a certain point, it is called high blood pressure or hypertension, which can be lowered and controlled with medication and changes in lifestyle and diet.

Bone marrow: (say: bone mair-oh) - Soft tissue found inside bones from which blood cells are produced and released into the bloodstream.

BrainStem: That portion of the Brain that connects the two Cerebral Hemispheres with the Spinal Cord. It has three major divisions: MidBrain, Pons, and Medulla Oblongata. This is the oldest part of the Brain, where most involuntary functions are controlled from. The area of Nerve Cells and Nerve Fibers at the base of the Brain still within the Skull that connects to the Spinal Cord. The Medulla Oblongata, Pons, and MidBrain constitute the BrainStem. It connects the Spinal Cord's Axons to the remainder of the Brain and is responsible for many essential functions. All but two of the 12 Cranial Nerves, enter or exit the Brain through the BrainStem.

BrainStem Auditory Evoked Response (BAER)- A painless, diagnostic test in which electrical impulses from the base of the Brain are recorded in response to repeated clicks during ElectroEnCephalography.

Bulimia nervosa: (say: buh-lee-mee-uh nur-vo-suh) - An illness defined by uncontrollable overeating, usually followed by making oneself throw up or purge (get rid of food) in other ways.


Cancer: (say: kan-ser) - When cells that are not normal develop and multiply. There are at least 200 different kinds of cancers, which can grow in almost any organ of the body.

Capillaries: (say: kap-il-air-eez) - Tiny blood vessels that branch through body tissues to deliver oxygen and nutrients and carry away waste products.

Carbon dioxide: (say: kar-bun dy-ocks-ide) - A body waste product that is a colorless gas.

CAT (or CT) Scan: A diagnostic, computerized imaging system that uses X rays to determine the density of different spots in the body. By producing a picture of the densities at thousands of spots in the Brain, a CT scan discloses normal and abnormal structures. However, all MR techniques provide superior imaging resolutions.

Cavity: Hollow space in the body containing one organ or more.

CD4+: A specific, Genetically determined type of T-Cell, that is thought to play a primary role, in MS & EAE. It is also known as a " Helper T-Cell"; because it activates all Acquired Immune Responses, only if it recognizes, the presented MHC Class II complex.

Celiac disease: (say: see-lee-ack diz-eez) - When the small intestine is hurt from eating gluten and other substances like it (gluten intolerance). Glutens are found in wheat, rye, oats, barley and other grains.

Cell: The body is made up almost entirely of many different kinds of Cells. Each Cell has a discrete inner core called the Nucleus, surrounded by CytoPlasm, and is encased in a Membrane separating it from other Cells.

Cell Membrane: The thin layer made of Proteins, Fats and Carbohydrates, which form the capsule of a Cell, and is its outside "Skin".

Cellular Immunology: Also called Adaptive or Acquired Immunity is one part of the body's Immune System. Its chief component is the Cytoxic T-Cell, which recognizes and destroys any Cell that is infected with a Virus, or a Bacteria, and it can directly kill Tumor Cells.

Central Nervous System: The part of the Nervous System covered by the Meninges. It includes the Brain, Spinal Cord, and Optic Nerves. The Nervous System comprises the Brain and Nerves: Afferent Nerves (from the Latin: ad = towards; ferro = I carry), which carry Sensory impulses from all parts of the Body to the Brain. Efferent Nerves (ex = from; ferro = I carry) through which "Messages" are conducted from the Brain to the Muscles and all of the Organs of the Body - The Somatic part of the Nervous System has Sensory components which convey Sensations from the Eyes, the Nose and other Sensory Organs to the Brain, and Motor components transmitting impulses to the Skeletal Muscles in the Limbs and Trunk permitting Voluntary control of Movements.

Centrocecal Scotoma: A Blind Spot that interferes with Central Vision, because part of what you should see does not register - due to DeMyelination, along the Optic Nerve.

Cerebellum: Part of the Brain, located above and behind the BrainStem, it regulates Balance and Coordination of Movements. It has no direct connection to any specific movement. ex: Posture Imbalance. The Cerebellum has no ability to learn; hence once damaged, it will continue to malfunction - Cerebellar disease is evidenced as Complex Motor Dysfunctions: changes in Speed and Cadence of Speech (Scanning Speech); Willed Movements resemble Tremor; and Eye Movement abnormalities (Nystagmus, Oscillopsia).

Cerebral Palsy (say: se-reeb-rul pahl-zee) - When injuries to the brain cause damage to the nerves and loss of movement. The injuries happen while a baby is growing in the womb or near the time the baby is born.

CerebroSpinal Fluid: (CSF) - The fluid surrounding the Brain and the Spinal Cord, containing Glucose (sugar), Proteins, and other substances that are also found in Blood. However, it does not normally contain Red or many White Cells. CSF is filtered from the blood supply and secreted by a vascular membrane (Choroid Plexus), within the Lateral, Third and Fourth Ventricles of the Brain.

Cerebrum: Forms the great bulk of the Brain and consists of two Hemispheres, which occupy the entire vault of the Cranium and are incompletely separated from each other by a deep median cleft, The Longitudinal Cerebral Fissure. Cervix (say: sur-vicks) - The narrow entryway between the vagina and the uterus. The muscles of the cervix are flexible so that is can expand to let a baby pass through when he/she is being born.

Chemokines - See: Cytokines

Chemokinesis: Indicates general movement, of many different cell types.

Chemotaxis: Literally means directed locomotion. It refers to the trail of secreted Cytokines that lead various Leukocytes, to a site of Inflammation.

Chemotherapy: (say: key-mo-ther-uh-pee) - Chemotherapy (pronounced: kee-mo-ther-uh-pee), which is often known as chemo, is a term used for medications to treat cancer. Cancer happens when cells in the body develop wrong and grow in an uncontrolled way. Since cancer cells tend to divide very fast, chemotherapy works by getting in the way of these cells dividing and trying to s the cancer from spreading. Sometimes chemo can cure the disease by helping to get rid of all the cancer cells in the body.

Chlamydia: (say: kluh-mid-ee-uh) - The most common sexually transmitted (passed) disease in the U.S. Many women do not have symptoms of chlamydia. Untreated, chlamydia can lead to pelvic infection and infertility (inability to become pregnant). People who are sexually active and who have multiple sexual partners are at the highest risk of getting chlamydia. A doctor can test and treat people for chlamydia.

Chronic Fatigue Syndrome: (say: kron-ick fah-teeg) - A very severe and long-term feeling of weakness and being tired, even after getting rest.

Circulatory system: (say: sur-kue-la-tor-ee sis-tem) - The heart, the blood, and the system of blood vessels that moves blood through the body.

Circumduction: A pattern of moving the Legs in which the person swings the upper Leg widely at the Hip. It is usually caused by partial Paralysis or Spasticity of the Limb.

Cleft lip and palate: (say: kleft lip and pal-it) - Abnormal growth of the lip and or roof of the mouth that happens before a baby is born. This can affect the way the lip looks, and also cause problems feeding as an infant and learning to speak.

Clinical depression: (say: klin-i-kul dee-presh-un) - Clinical, or major, depression is an illness that involves the body, mood, and thoughts. It affects the way a person functions, eats and sleeps, feels about herself, and thinks about things. Depression is not the same as a passing "down" mood. It is not a sign of personal weakness or a condition that can be willed or wished away. This condition can be treated with medication and counseling.

Clonus: Involuntary movement of rapidly alternating contraction and relaxation of a muscle. Ankle Clonus is the most common form of Clonus. Reflexive Spasms in the Calf Muscles, cause the Foot and Leg to bounce up and down, when the Knee is bent and the toes are on the floor. Clonus is a hallmark Sign of Spasticity - (Also See: Neurological Examination).

Clotting: (say: klod-ing) - The process by which the body forms a plug to seal damaged blood vessels and s bleeding.

Cognition- High level functions carried out by the human Brain, including: Comprehension and use of Speech, Visual Perception and Construction, Calculation Ability, Attention (information processing), Memory, and Executive Functions such as Planning, Problem-Solving, and Self-Monitoring.

Complement: Nine Serum proteins activated in sequence by an Antigen, forming Antigen-AntiBody-Compound. (Symbol 'C'). It is part of the Non-Specific Immune System that generally deals with Bacteria infections - Complement upregulates Macrophage Cells, aiding their ability to find and digest foreign cells. It also calls Neutrophil Cells to the scene, which can kill Bacteria by producing Peroxide. (Also See: Complement System Products

Compression: To apply pressure to stop bleeding or prevent further injury.

Computed Tomography - See: CAT scan.

Coordination: An organized working together of muscles and groups of muscles aimed at bringing about a purposeful movement, such as walking or standing.

Corpus Callosum: Is a thick band of more than 200 million Myelinated transverse Nerve fibers. The Corpus Callosum is the largest and most important Commissural Fiber that interconnects the two Cerebral Hemispheres. It lies at the bottom of the Longitudinal Cerebral Fissure and is a very frequent site for MS lesions - Its underside forms the roof of the two Lateral Ventricles; the front terminates in the Frontal Lobe and is named the Forceps Anterior or (Minor). The back portion (the Forceps Posterior or Major) connects to the Temporal and Occipital Lobes and to the Hippocampus Bands - Peduncles of the Corpus Callosum.

Cortex: Is the outer layer of any organ. Cortex, Cerebral - The outer layer of Nerve Cells that covers the entire surface of the Cerebral Hemispheres. Thinking and other Complex Neuronal Activity occur in the Cerebral Cortex - A 2.5 to 4.0 mm. thick layer of Neurons containing Gray Matter.

Cortex, Association: The Cortex immediately adjacent to and closely connected to The Primary Sensory Cortex. Association Cortex gives form and meaning to raw Sensory messages received at the Primary Sensory Cortex through widespread connections to many parts of both sides of the Brain.

CorticoSpinal Tract - See: Pyramidal Tract

CorticoTropin - See: ACTH

Cortisone: A Steroid Hormone recommended to some people with Multiple Sclerosis, to reduce acute inflammations in the CNS. Cortisone treatments carry significant risks and should NOT be used for long term treatment.

Cystic Fibrosis: (say: sis-tick fy-broh-sis) - A disease that causes both breathing and digesting problems. Cystic fibrosis runs in the family.

Cytokines: are proteins (usually GlycoProteins) of relatively low molecular mass and often consisting of just a single chain. They are chemicals secreted by various Leukocytes to activate other cells, coordinate, and regulate all important biological processes: Cell Growth, Immunity, Cell Activation, Inflammation, Tissue Repair, Fibrosis and Morphogenesis - Cytokine Mechanisms: Autocrine - effects only the producing cell Endocrine - travel through the bloodstream, acting on numerous distant cell. Paracrine - acts locally on target cells, adjacent to the producing cell - Some Cytokines (ie: IL-8) are also Chemotactic for specific cell types, and are now called Chemokines. Although Cytokins are considered to be a Family, this is a Functional rather than a Structural concept; these Proteins are not all chemically related. (ex: Interferons, Tumor Necrosis Factor, and InterLeukins).


Dantrolene Sodium (Dantrium): An AntiSpasticity medication.

Deep Tendon Reflexes: The involuntary muscle jerks that are normally produced, when the tendon is tapped at certain spots on a limb with a hammer. In MS, the tone of these Reflexes are heightened by lack of Cortical inhibition (Spasticity).

Decompostion of Movement: inability to sequence properly fine, coordinated acts.

Decubitus: An Ulcer (Sore) of the Skin resulting from pressure and lack of movement, such as occurs when a person is mostly in a bed or a wheelchair. The Ulcers occur most frequently in areas where the bone lies directly under the Skin, such as the Elbow, Hip, or Tailbone.

Dementia: A generally profound and progressive loss of intellectual function, sometimes associated with personality change, that results from loss of Brain substance, and is sufficient to interfere with a person's normal functional activities.

DeMyelination: The destruction, loss, or removal of the Myelin Sheath, which normally insulates some Axons, by a disease process. Multiple Sclerosis is a Chronic CNS Disease that results in DeMyelination (Lesion, or Plaque), following damage to Axons, Myelin, Oligodendrocytes, or Neurons.

Dendrite: The thin, afferent Process of a Neuron that carries newly received Nerve Impulses towards the Cell Body.

Dendrite Cell: A Phagocyte, these Leukocytes are found in the Spleen and other Lymphoid Organs; they typically use threadlike tentacles to enmesh Antigen, which they present to T-Cells.

Diabetes: (say: dy-uh-bee-teez) - When there is too much sugar in your blood. It can be caused by having not enough of the chemical that monitors blood sugar, called insulin, or by having a resistance in your body to insulin.

Diagnosis: The art or act of identifying a disease from its Signs and Symptoms. The MS diagnosis requires clinical evidence (a positive, objective finding) on Neurological Examination of two or more CNS White Matter lesions, in a person between 10 - 60 years old that occurred at two separate and distinct time periods, and of whom no other medical explanation exists ("Poser Criteria").

DienCephalon: is the part of the Brain between the BrainStem and the Cerebrum. Its main components are: Thalamus, SubThalamus, HypoThalamus, and EpiThalamus.

Diplopia - Double Vision, or the simultaneous awareness of two images of the same object that results from the failure of the two Eyes to work in a coordinated fashion. Covering one Eye will eliminate Double Vision, by erasing one of the images. (Also See:Fasciculus, Medial Longitudinal Disability - A disability (resulting from an Impairment) is a restriction or lack of ability to perform an activity in the manner or within the range considered normal for a human being. Permanent MS disability is the result of Axons that have been severed and/or Atrophied; while the temporary dysfunction experienced during an exacerbation is short-term, resolving after the Inflammation clears. (See: Normal-Appearing White Matter & Axons & Disability)

Disseminated: Scattered or distributed (Multiple).

Dizziness: A feeling of internal uneasiness, confusion, or light-headiness (passing out). The term Dizzy is commonly confused with Vertigo (a sensation your surroundings are spinning). While the feeling that you are actually spinning, not your surroundings is Dizziness, caused by DeMyelination within the Cerebellum or its Nerve Pathways.

Douching: (say: doo-shing) - Douching is rinsing or cleaning out the vagina, usually with a prepackaged mix of fluids. The water or solutions are held in a bottle and squirted into the vagina through tubing and a nozzle. Health care providers do not suggest douching to clean the vagina. Douching changes the delicate chemical balance in the vagina, which can make a woman more prone to bacterial infections.

Down Syndrome: (say: down sin-drohm) - When an extra copy of a chromosome is present when a baby develops. (A chromosome holds a cell's genetic information for a person.) The extra chromosome usually causes mental and physical abnormalities.

Drug dependence: (say: drug dee-pend-ins) - An addiction to drugs, or the inability to s using harmful substances despite the harmful problems they cause.

Dysarthria: Slurring, inappropriate phrasing and lack of modulation in Speech volume. Both Slurred and Scanning Speech are very common types of Motor-Dysarthrias and are generally a result of Lesions (DeMyelination), in the BrainStem or within its connecting Nerve pathways - Poorly articulated Speech resulting from Neural dysfunction of the Muscles controlling Speech. The content and meaning of the spoken words remain normal.

Dysdiadochokinesia: Inability to perform rapid alternating movements, such as the nose to finger Neurological Test.

Dysesthesia: Distorted or Unpleasant Sensations experienced by a person when the Skin is touched. It is often referred to as an unpleasant ''Burning'' Sensation.

Dyskinesia: Are stereotypical, involuntary movements that affect muscle groups in varying combinations. MyoClonus and Dystonia are the most common forms of Dyskinesia seen in MS.

Dysmetria: Inability to control range of movements. A disturbance of coordination, caused by lesions in the Cerebellum. A tendency to over or under estimate the extent of motion needed to place an arm or leg in a certain position.

Dysmenorrhea: (say: dis-men-or-ee-uh) - Painful menstrual periods that can also go along with nausea and vomiting, and either constipation or diarrhea. Dysmenorrhea is common among adolescents.

Dyspepsia: Indigestion, a feeling of being over stuffed.

Dysphagia: Difficulty in swallowing either solids, liquids, or both. It causes aspiration (food or saliva enters the airway), choking, and slow swallowing (possibly leading to inadequate nutrition). MS may cause Dysphagia, if Lesions develop in the BrainStem or along its connecting Nerve pathways, disrupting the sequencing and control of motor programs that govern muscles regulating swallowing (Mouth, Pharynx and Esophagus).

Dysphonia: Disorders of voice quality (including poor pitch control, hoarseness, breathless, and hypernasality) caused by spasticity, weakness, and in-coordination of muscles in the throat and mouth.

Dystonia: movement disorders where sustained muscle contractions cause twisting and repetitive movements or abnormal postures. The movements are involuntary and sometimes painful, they may affect a single muscle; a group of muscles such as those in the arms, legs, or neck, or the entire body - Dystonia result from an abnormality in the Basal Ganglia, where some of the messages that initiate muscle contractions are processed. Scientists suspect a defect in the body's ability to process these Neuro-Transmitters prevents Neurons from communicating with each other. Some of which include: GABA (Gamma-AminoButyric Acid) is inhibitory Dopamine is inhibitory Acetylcholine is excitatory - In movement, Acetylcholine released at Nerve endings causes muscle contraction. NorEpinephrine and Serotonin are inhibitory Neuro-Transmitters that help to regulate Acetylcholine.


EAE (Experimental Allergic EncephaloMyelitis): A disease induced in lab animals that is similar to what is seen in humans with MS.

Edema - Swelling in the Brain or elsewhere caused by the abnormal accumulation of fluid.

Eating disorders - An eating disorder is a severe illness that requires help from a health care provider, the sooner the better. Bulimia nervosa is an eating disorder where a person binges, or eats a large amount of food all at once and then purges, or forces themselves to vomit, takes laxatives, or diuretics (water pills). Starving yourself by eating very little or nothing at all is another eating disorder called anorexia nervosa. People who have this condition can have a strong fear of body fat and weight gain. Binge eating disorder happens when a person cannot control her desire to overeat and often keeps the extreme eating a secret. Unlike bulimia, with binge eating disorder, a person does not purge her food. Extreme exercise to control weight is also a type of eating disorder.

ElectroEnCephalography (EEC): A painless, diagnostic technique that records electrical activity in the Brain. (See: Evoked Potential Tests)

Emboli: Are small particles that Occlude (Block) the circulation of smaller Blood Vessels (Micro-Circulation).

Embolization: Is the process of Occlusion by Emboli.

EnCephalitis: Inflammation of the Brain, sometimes called "sleeping sickness" caused by Viruses and other Microscopic organisms.

Endometriosis: (say: en-doh-mee-tree-oh-sis) - A condition where tissue that normally lines the uterus grows in other areas of the body. This can cause pain, irregular menstrual bleeding, and infertility for some women.

Endometrium: (say: en-doh-mee-tree-um) - The lining of the uterus.

Epilepsy: (say: ep-il-ep-see) - A brain disorder that causes seizures, which are uncontrollable body movements.

Epidemiology: The science concerned with the cause, frequency and distribution of an infectious process or a physiological state in a human community.

Epitope: A single Antigenic Determinant that functionally is the portion of an Antigen which combines with an AntiBody. Epitopes are surface markers (GlycoProteins) present on all cells, consisting of different combinations of Amino Acids - Only this molecular configuration is recognized and bound by an AntiBody or T-Cell. Each Antigen normally displays more than one Epitope and each one, may attract a different Immune member. (See: GlycoProteins)

Erythrocytes: (say: er-ith-roh-syts) - Redblood cells.

Estrogen: (say: es-tro-jin) - A female hormone produced by the ovaries. Estrogen plays important roles in puberty, the menstrual cycle, and in reproduction.

Etiology: The study of all factors that may be involved in the development of a disease, including the patient's susceptibility, the nature of the disease-causing agent, and the way in which the person's body is invaded by the agent.

Evoked Potentials: Electrical signals recorded from the CNS in response to repetitive stimuli, such as a clicking noise (Hearing), flashing light (Vision), or a slight electrical shock (Sensory). Evoked Potentials utilize ElectroEnCephalography to record how long the message takes to reach the Brain. - This test is useful in the diagnosis of MS because it can confirm the presence of a suspected lesion, which was not shown by a MRI scan, or identify the existence of an unsuspected lesion (Clinically Silent) that has not produced any symptoms.

Exacerbation: An increase in the severity of symptoms. Exacerbations of MS usually involve an increase in definite symptoms, lasting weeks or months. During the attack, numerous individual symptoms may come and go in succession. Acute attacks are usually followed by complete or partial remission (the abatement or diminution of symptoms) - A worsening or flare-up of Neurologic Signs and symptoms (such as Numbness, Weakness or Lost Vision), usually associated with Inflammation and DeMyelination in the Brain or Spinal Cord. The opposite of exacerbation is remittance - The appearance of new symptoms or the aggravation of old ones, lasting at least 24 hours. (Poser's Criteria)


Fallopian tubes: (say: fa-lo-pee-in) - The organs that connect the ovaries to the uterus. There is a fallopian tube on each side of the uterus. When one of the ovaries releases an egg, it travels through the fallopian tube toward the uterus. Fertilization (when a man's sperm and a woman's egg join together) usually happens in the fallopian tube.

Fasciculus, Medial Longitudinal (MLF): A Nerve Tract in the BrainStem carrying instructions that coordinate horizontal Eye movements. The MLF coordinates the two Eyes, when they look to the left or to the right. A lesion in the MLF interrupts that coordination and the Eyes do not turn in precisely the same direction, at exactly the same time. Thereby producing two images in the Brain of the same scene - Diplopia (Double Vision).

Fatigue (Lassitude): Is a debilitating kind of overall weariness, which is unpredictable and out of proportion to the activity. Any increase in your body temperature will temporarily worsen fatigue; conversely, air-conditioning or a cool drink will lower your temperature, enabling you to feel better and continue.

Fecal Incontinence: Loss of control of bowel movements.

Flare-up - See: exacerbation.

Focal: A specific defined location or structure: of, relating to, being, or having a focus.

Focal Deficits: Impaired strength or Sensation over part of the body.

Footdrop: Impaired or Absent Voluntary Dorsiflexion of the foot - The normal Heel-Toe pattern of Walking (Gait) is disturbed, causing the toes to touch the ground before the Heel, resulting in tripping and lose of balance.

Frontal Lobes: The largest Lobes of the Cerebrum. The Anterior (Front) part of each of the Cerebral Hemispheres, is the control center for Learning, Behavior, Judgment, and Personality. The back part of the Frontal Lobe is the Motor Cortex which controls Voluntary Movements.


Gadolinium: A chemical compound which can be administered to a person undergoing a MRI procedure, to enhance the distinction between new vs old lesions. It also increases the scan's sensitivity, which enables the imaging of lesions that would be missed on un-enhanced T1 and T2 scans.

Gait Ataxia: Broad-based, staggering patterns of walking usually a sign of Cerebellar damage, causing poor coordination of the Limbs.

Gamma Globulin (ImmunoGlobulin) - A protein fraction of Blood Serum that contains many different AntiBodies. Increased percentages of ImmunoGlobulin and the presence of Ig Clonal Bands are characteristic of MSers' CerebroSpinal Fluid; but they are not conclusive proof, you have MS

Ganglia: Are collections of Nerve Fibers and Neuron Cell Bodies. Neurons are large cells with appropriately large nuclei. Patches of Basophilic material and pigment are often seen in Ganglion Cell CytoPlasm.

Gene: The biological unit of Heredity. Genes determine the structure and function of all proteins in the body. In turn, these proteins govern body shape and function.

Genes: (say: jeans) - Genes come from both parents and are responsible for inherited characteristics, such as eye and hair color. Genes are in all body cells.

Genital region: (say: jen-i-tul) - The external reproductive or sex organs (sometimes referred to as a person's private parts).

Genetic Determinant: The unique Antigens that identify all Cells as Self, due to Heredity, ie, HLA, to the Immune System.

Gingivitis: (say: jin-jih-vyt-is) - Inflammation of the gums, the first stage of gum disease. Gingivitis is caused by plaque deposits, which are made up of bacteria, mucus, and food debris. Injury to the gums from harsh brushing or flossing can also cause inflammation.

Girdle Sensation (MS Hug): A sensation of feeling a tight band (like wearing an overly tight girdle or corset) around your trunk that is experienced by some MSers, who have a lesion (old or new) on the Spinal Cord. If it prevents you from taking in a full breath, it is best to treat with a course of IV MethylPrednisolone -This Hug is usually the first indication of a new exacerbation, when the inflammation is primarily centered around the Spinal Cord. Alternately, the MS Hug can also be brought on by an increase in temperature (body core or ambient); if you have a pre-existing Spinal lesion. (Also See: Transverse Myelitis)

Glands: (say: glanz) - A collection of Cells specialized to secrete materials unrelated to their ordinary needs. For instance, the Salivary Gland is a collection of Cells that secrete Saliva. Those Cells have no use for the product, which aids digestion in the Mouth and Stomach.

Glia Cells: outnumber Neurons by about five to one in the Nervous System, they have processes but do not form or conduct Action Potentials, and retain the capacity to divide throughout life.

Gliosis (Glial): Scars that are produced by enlargement of Astrocyte processes. When a portion of the CNS is damaged (Neuron or Axon), Astrocyte processes enlarge and replace the damaged tissue. This process is referred to as Gliosis, while the resulting permanent scar tissue is called Plaque (Sclerosis).

GlucoCorticoid Hormones (Steroids): Hormones that are produced by the Adrenal Glands in response to stimulation by AdrenoCorticoTropic Hormone (ACTH) from the Pituitary Gland. These Steroids (Prednisone, Prednisolone, MethylPrednisolone, Betamethasone, Dexamethasone), which can also be manufactured synthetically, are artificially increased to serve both an Immuno-Suppressive and an Anti-Inflammation role in the treatment of acute MS exacerbations.

Granulocytes: (say: gran-you-lo-syts) - A subset of Leukocytes (PolyMorphoNuclear Leukocytes) that are part of the Adaptive Immune System and includes Neutrophils, Eosinophils, and Basophils.

Gray Matter: Portions of the CNS where Nerve Cell Bodies are concentrated. Cortex is Gray Matter. So are the Anterior and Posterior Horns of the Spinal Cord and more.


Halitosis: (say: hal-i-toe-sis) - Offensive or bad breath.

Heat Sensitivity: Causes a transient worsening of symptoms and may make vision blurry (Uhthoff's Syndrome). Bodily functions return to normal, when the body cools off and the Neuron can resume transmitting Nerve Impulses - Without its Myelin coating, all CNS tissue is more sensitive to heat and prone to stop transmitting electrical signals (Conduction Block), when the body's core temperature is increased by just 0.5 degree C.

Hematemesis: Blood in vomit.

Hemianopsia: One-sided Visual Field loss.

Hemiparesis: Sensory loss or weakness of the face, Arm and Leg on one side of the body.

Hemiplegia: Paralysis of one side of the body, including one Arm and one Leg.

Hemoglobin: (say: heem-oh-glo-bin) - Substance containing iron found in red blood cells, which helps the blood carry and deliver oxygen to body tissues.

Hemophilia: (say: heem-o-feel-ee-ah) - A disease that makes it difficult for the blood to clot, which is how the blood sticks together to s flowing. Without clots, a simple cut can cause someone to lose a dangerous amount of blood. This disease affects mostly boys.

Hepatitis: (say: hep-uh-tyt-is) - Inflammation of the liver, caused by infections from bacteria, viruses, or toxins such as alcohol or drugs. There are different types of hepatitis, including Hepatitis A, B, C and autoimmune hepatitis.

Herbal supplements: (say: er-bul sup-le-ments) - Herbal supplements are different types of medicines that come in a variety forms, such as teas, vitamin pills, or creams. There has not been a lot of research done on herbal supplements to really know how well they work or how safe they are, so it is important that you ask your doctor before taking anything that he or she has not given you.

Histamine: A chemical present in cells (Mast Cells) throughout the body. Its release opens Endothelial Cell junctions in the Venules' Blood-Brain Barrier and upregulates Adhesion Molecules. It is one of the substances responsible for Inflammation, stimulates production of Stomach Acid, and narrows the Bronchi in the Lungs.

Histocompatibility Genes: Are a category of DNA Genes called, Class II Major Histocompatibility complex Genes. They create the HLA Antigens by which the Immune System recognizes self.

HIV: (say: H-I-V) - HIV stands for the human immunodeficiency virus, which destroys the immune system that protects the body. This makes it hard to fight infections. People who have HIV may not have any symptoms for up to 10 years, but they can give it to others through unprotected sex and sharing drug needles. HIV leads to full-blown AIDS.

Hodgkin's lymphoma: (say: hodj-kinz limf-oh-muh) - A type of cancer that affects the tissue found in lymph nodes (glands that protect the fluids in your body), the spleen, the liver, and bone marrow.

Homicide: (say: HOM-uh-side) - The killing of one person by another. Homicide is not legal and is a punishable crime.

Hormone: (say: HOR-moan) - A substance secreted in the body and carried through the Blood-Stream to organs and tissues, where it serves a regulatory function (Hormones travel in the blood and can act, far from the site of secretion). (Also See: GlucoCorticoid Hormones & Pituitary Hormones)

Human Leukocyte Antigen (HLA) - The Self-Made-Antigen (Major HistoCompatibility Gene) displayed on the surface of all cells that identifies them to the Immune System, as belonging to self. These Antigens must be presented with Antigenic Peptides, in order for T-Cells to begin an Immune Response.

HPV: (say: H-P-V) - A sexually transmitted disease that can cause wart-like growths on the genitals. There are many types of HPV, and some types do not cause growths. Regular pap tests or HPV tests can catch the virus. HPV can lead to pre-cancerous sell changes in the cervix, so detection and treatment are important.

Human T-Cell Lymphotropic Virus type 1 (HTLV-1)-: A RetroVirus currently being studied that operates in human T-Cells and causes a disease called Tropical Spastic Paraphesis.

Hypoxia: Indicates a severe Oxygen shortage in tissue.


Iatrogenic: A condition that appears as a result of treatment of another condition.

Idiopathic: Of unknown cause.

Immune System: (say: im-yoon) - The Immune System is a collection of Cells and Proteins that works to protect the body from potentially harmful, infectious Microorganisms (microscopic life-forms), such as Bacteria, Viruses and Fungi - It is a defense mechanism characterized by recognition of Non-self, Specificity, and Memory. It has two basic components: Innate Immunity and Acquired

Immunity. - The Immune System plays a role in the control of Cancer and other diseases, but also is the culprit in the phenomena of Allergies, Hypersensitivity, the rejection of Transplanted Organs, AutoImmune Diseases, and Medical Implants. Having protection or resistance to a particular disease or poison, ie, Gamma Globulin.

ImmunoGlobulin: A group of GlycoProteins (AntiBodies), present in Serum and tissue fluids that recognize and bind to Antigens. They are produced by Plasma Cells and are integral in Adaptive Immune Responses. There are five classes of Immuno-Globulins (Ig): IgG, IgA, IgM, IgD, IgE.

Immunizations: (say: im-you-niz-a-shuns) -Immunizations keep people from getting sick by immunizing, or protecting, the body against certain infectious diseases. Vaccines contain parts or products of infectious organisms or whole germs that have been changed or killed. A vaccine gets the body's immune system ready to fight off infection by that germ. Most immunizations that prevent you from catching diseases like measles, whooping cough, and chicken pox are given by a shot.

ImmunoSuppression: Any form of treatment or drug, which slows or inhibits the body's usual Immune Responses. Some examples used to treat MS are: Cyclosporin, Methotrexate, and Azathioprine.
Impairment - Any loss or abnormality of Psychological, Physiological, or Anatomical structure or function. It is a deviation from the person's usual biomedical state. An impairment is thus any loss of function directly resulting from injury or disease.

Impotence: Poor or Absent erection of the Penis.

Incidence: The number of new cases of a disease in a specified population over a defined time period.

Incontinence: The inability to hold urine or stool until urination or defecation is intended.

Inflammation: A tissue's Immunological response to injury, characterized by mobilization of White Blood Cells and AntiBodies, Swelling, and Fluid Accumulation.

InfraTentorial: Interior Cerebral areas (DienCephalon), along the Ventricles, just below the under-surface of the Temporal and Occipital Lobes. Most common InfraTentorial MS lesion sites: The Floor of the Fourth Ventricle - The Cerebellar Peduncles - The Surface of the Pons

Insulin: One of many Hormones which helps the body, change the food we eat into energy; Insulin helps us store energy for later use. After we eat, it causes sugar (Glucose) to leave the blood and enter the body's cells - to make fat, sugar, and protein. Between meals, it aids in the utilization of stored fat, sugar, and protein.

Interferon - An interfering Protein that neutralizes Virus, it is produced by CytoToxic T-Cells of the Immune System, in response to foreign Nucleic Acids (produced by Viruses and Bacteria), thereby protecting uninfected cells - Interferon-alpha () and Interferon-beta, form the Type 1 class of Interferons; while Interferon-gamma () is a Type 2 Interferon. These Proteins are Anti-Viral Cytokines that are also, potent Immune Regulators and Growth Factors.

InterLeukins (IL-1 to IL-18): A well-characterized group of Cytokines, mainly produced by Leukocytes, which mostly act upon other Leukocytes. Their main targets for actions, vary from T-Cells and B-Cells, to Fibroblasts and Endothelium - They have a broad spectrum of functional activities that regulate the activities and capabilities of many cell types and regulate Inflammation and Immune Responses.

Intractable: Difficult to cure or alleviate.

Intrathecal: Occurring in the space under the Arachnoid membrane, which surrounds the Brain and Spinal Cord (generally within the CerebroSpinal Fluid).

Ischemia: Is an insufficient Blood Supply to an Organ or Tissue.


Lateral SpinoThalamic Tract: A Sensory Nerve Tract in the Anterior-Lateral (Front-Side) portion of the Spinal Cord. Interruption of the LST, results in loss of Pain and Temperature sensations below the level of the lesion, on the Opposite Side of the of the body.

Lesion: Any damage to tissue structure or function. A Scar is a Lesion. So is Cancer, a MS Plaque, a Stomach Ulcer or a Pimple. On T2 MRI scans, old lesions register as *Black Holes- HypoIntense (less tissue) areas. New inflammatory lesions are seen as, *Bright Spots- HyperIntense (higher fluid content) areas. - MS lesions on conventional MRIs [T2], first appear as small, ovid shaped, focal bright spots having discrete borders. Cerebral lesions are located centrally, near the MidLine, asymmetrically arrayed, deep within the White Matter, and always surround a blood vessel (Venule) that is near CerebroSpinal Fluid (Ventricles, or Spinal Cord).

Leukocytes: (say: loo-ko-syts) - Any of the blood cells that are colorless, lack Hemoglobin, and contain a Nucleus (also called White Blood Corpuscle).

Lhermitte's Sign: An electrical sensation (Shock, Lightning Bolt) that some MSers experience, when flexing the neck, tilting, or lowering the head towards the chest. It begins at the base of the skull, runs down the Spine and into the limbs, before exiting through the hands or feet.
(Also See: Tic-Douloureux)

Ligand: A Molecule or Ion that can bind another Molecule.

Lobe (Of The Brain): A major division of the Cerebral Hemisphere. Each Cerebral Hemisphere is divided into: Frontal Lobe, Parietal Lobe, Occipital Lobe, Temporal Lobe, and Limbic Lobe.

Lupus: (say: loo-pus) - One of the diseases that causes the immune system, which normally protects the body, to actually attack it. Lupus can cause problems with the skin, joints and organs on the inside of the body.

Lymphocytes: (say: limf-oh-syts) - A variety of White Blood Cells (Leukocytes), which are part of the body's Cellular Immune System - White Blood Cells play a large role in the Immune System, by responding to Antigens and triggering reactions in other cells. Are produced by Bone Marrow Stem Cells and depending on their site of subsequent maturation, they develop into either: B or T-Cells.

B-Cells: are responsible for Humoral Immune Responses, they produce Immuno-Globulins (AntiBodies) to fight ExtraCellular infections (Bacteria, Fungus, etc.).

T-Cells: are responsible for Cell-Mediated Immune Responses (Cellular Immunology) including both effector and regulatory cells. Helper T-Cells prime both AntiBody-mediated and Cell-mediated effectors for the attack, while Suppressors await the signal to change, slow, or end the assault.

Natural Killer Cells (NK): recognize classes of cells and destroy tumor cells on contact, without needing a co-stimulator signal.

CytoToxic T-Cells (CD8+): handle the destruction of host cells, which have become infected by Viruses or other IntraCellular Pathogens.

Helper T-Cells (CD4+): heighten the production of AntiBodies by B-Cells and regulate the activities of all effector cells. A functional subclass of T-Cells that helps to generate CD8+ Cells and cooperate with B-Cells in the production of AntiBody-mediated responses - CD4+ Cells only recognize Antigens that are presented in association with MHC Class II molecules.

Suppressor T-Cells: suppress B-Cell activity and seem to be in short supply during a MS attack (exacerbation).
- A functionally defined population of T-Cells, which reduce the Immune Responses of other T-Cells or B-Cells, or switch the response onto a different pathway.


Macrophage: Develop from Monocytes, a Phagocyte Cell that helps initiate and is involved in all stages of Immune Responses. It recognizes and can digest (Phagocytize) all foreign Antigens (ie. Bacteria, Viruses) and Cell Debris. Macrophages are also an integral part of DeMyelination and participate in tissue repairs - In the CNS, they are called Microglia Cells, and Kupffer Cells in the Liver, where they Phagocytize Bacteria, other Pathogens, and old red blood cells.

Macrophage-Activating Factor (MAF): Actually several Cytokines, including Interferon, released by activated T-Cells, which together induce activation of Macrophages, making them more efficient in Phagocytosis and CytoToxicity.

Mast Cells: Develop from Basophil Cells (PolyMorphoNuclear Leukocytes), they reside in tissues, regulating Vascular Permeability (Blood-Brain Barrier) and Smooth Muscles. They possess IgE receptors, participating in immediate hypersensitivity reactions by de-granulation (Release) of Heparin, Serotonin, Histamine, and other VasoActive Amines.

Medulla Oblongata: The lowest major segment of the BrainStem.

Memory: (See: Cognition)

Menarche: (say: men-r-kee) - The first menstrual period or beginning of menstruation.

Menopause: (say: MEN-o-pawz) - The last menstrual period or end of menstruation. The average age of menopause is 50. After menopause, a woman can no longer become pregnant.

Meningitis: (say: men-in-jyt-is) - A dangerous infection that affects the brain and spinal cord.

Menstruation: (say: men-stroo-ay-shun) - The monthly period or menstrual bleeding. During menstruation, the extra blood and tissue that built up inside the uterus during the menstrual cycle is expelled through the vagina, usually over a period of 3-7 days.

Muscular Dystrophy: (say: mus-kew-lar dis-trof-ee) - A group of disorders that causes muscles to be weak and causes loss of muscle tissue.

MicroEmboli: Refers to any small Emboli that predominantly Occlude (Block) the MicroCirculation.

Microglia - (See: Glia Cells - Microglia)

Monoclonal AntiBodies: Are laboratory-produced AntiBodies, which can be programmed to react against a specific Antigen, in order to suppress the Immune Response.

Monocyte Cells: Develop from Stem Cells, are effective Antigen Presenting Cells, and patrol the bloodstream, searching for Antigens. In time, Monocytes migrate into tissue and develop into Macrophages.

MR or MRI - (See: Nuclear Magnetic Resonance). Multiple Sclerosis - Is a Chronic Neurologic Disease of the Central Nervous System (CNS), occurring only in humans. MS is classified as both, a DeMyelinating and an Axonal Disease.(See: Multiple Sclerosis as a Neuronal Disease)- Although increasing evidence points to an AutoImmune aspect, no single Antigen or Immune System Dysfunction has been identified, so the cause of MS remains unknown. (See: Multiple Sclerosis - The range of MS disease patterns, stages, and symptoms, with explanations of today's standard diagnostic tests.)

Myelin: A fatty (Lipid) substance forming a multi-layered sheath around some Nerve Fibers (Axons) in the Central, Autonomic and Peripheral Nervous Systems. Within the CNS, Myelin is formed by Oligodendeocytes and consists of their Cell Membranes (CytoPlasmic Extensions), which wrap themselves around Axons - This Myelin Sheath covers and insulates sections (InterNodes) of CNS Axons, thereby reducing the electrical Capacitance between a Neuron's negatively charged Axonal Membrane (InterNodal Axolemma) and the surrounding positively charged ExtraCellular Fluid - Myelin greatly increases the conducting velocity of an Action Potential; while expending much less energy than an Un-Myelinated Axon would require, to send an identical Action Potential, along the same distance.

Myelin Basic Protein: One of the components of Myelin, which may be increased in the CerebroSpinal Fluid of some - but not all MSers - following a DeMyelinating episode.

Myelitis: An inflammatory disease of the Spinal Cord. In Transverse Myelitis, the inflammation spreads across the Spinal Cord, resulting in a loss of its normal function to transmit Nerve impulses up and down, as though the Spinal Cord had been severed.

MyxoVirus: A Virus which causes disease in Mucous Tissue such as the Throat, Mouth, or Lung. ex: (Influenza) See: Virus


Necrosis: Is tissue decomposition resulting from the loss of its Blood and Oxygen supply, Burns, or other severe injuries. It can also be caused by some medications, commonly used to treat MS - Necrosis of the skin occurs after a subcutaneous injection, when the body is intolerant of the medication. Necrosis of the Hip and Shoulder Joints are caused by the Long-Term use of Steroids. (See: Steroids)

Nerve Fibers: (Axons) - Are long, sparsely branched Processes, having non-changing diameters that extend from a Neuron's Cell Body and connect another Neuron's Axon, Dendrite, or Cell Body and/or bodily organs that compose their Neural Network - A bundle of Nerve Fibers (Axons). The Fibers are either: Afferent - leading towards the higher Brain (CNS) and serving in the Perception of Sensory stimuli of the Skin, Joints, Muscles, and Inner Organs; Efferent - leading away from the higher Brain and Mediating contractions and relaxations of Muscles or Organs.

Nerve Impulse: The electrochemical charge (Action Potential) carried by an Axon.

Neurologic Disease - Any disorder of the Nervous System. There are many different neurologic diseases, among which is Multiple Sclerosis.

Neuron: An individual Nerve Cell and the key data-processing cell of the Nervous System. Each has a Nucleus within a Cell Body and one or more Processes (Extensions) called Dendrites and Axons. NeuroTransmitters - Are chemicals (Small Molecules or Hormones), stored in small Synaptic Vesicles clustered at the tip of the Axon (terminal buttons) - When a Nerve Impulse arrives for transmission to the next Neuron, they cross the Synapse enabling message transmission to another Neuron or the Stimulation of an Effector Cell (Muscle or Gland) - When a NeuroTransmitter is received, it either Excites (Depolarizes) or Inhibits (Hyperpolarizes) the PostSynaptic Neuron. More than 100 organic molecules are thought to act as NeuroTransmitters - Some examples are: Acetylcholine, NorEpinephrine, GABA, Serotonin, and Dopamine, although each acts in different responses. Some are Excitory, such as Acetylcholine, Serotonin, NorEpinephrine, and Dopamine. Some are associated with Relaxation, such as Dopamine and Serotonin.

Neutrophils: A Phagocyte member of Leukocyte Cells, they are the Adaptive Immune System's first line of defense against Bacterial infections. After leaving nearby Blood Vessels, these cells follow chemicals produced by Bacteria in a cut or scratch and proceed to locate and eliminate the invader.

Nodes Of Ranvier: Are the only gaps between Myelin sections (InterNodes) along Myelinated Axons, where Sodium (Na+) and Potassium (K+) can be exchanged (Salatory Conduction); hence, continuing the Nerve signal's rapid transmission, to its target. They are crucial electrical refresher sites, where Action Potentials are restored.

Nuclear Magnetic Resonance (MRI, MR, NMR): A diagnostic test that uses the magnetic properties of different substances in a Magnetic Field to produce images of the Brain, Spinal Cord, and other soft tissues of the Body. A MRI shows areas of Sclerosis (Lesion, Plaque), when they are larger than 2mm (Macroscopic Lesions) - Scans can NOT show Microscopic Lesions, as they are too small for current imaging resolutions; but are included in your Lesion Load and Atrophy totals.

Nocturia: Inability to hold urine while sleeping, resulting in bed-wetting and/or disrupted sleep, due to repeated bathroom trips. (See: Neurogenic Bladder, Urgency with Hesitancy)

Nystagmus: A back and forth twitching Eye movement (Rhythmical jerking movements), with the fast component maximal, towards the side of the Cerebellar Lesion. Characterized by rapid, involuntary Eye movements, in the horizontal or occasionally, the vertical direction.
(Also See: Oscillopsia; Optic Neuritis; Retrobulbar Neuritis)


OligoClonal Bands (Gamma Globulin Bands): A positive finding from the chemical analysis of ImmunoGlobulin (IgG) found in CerebroSpinal Fluid. IgG Banding indicates an Intrathecal production of AntiBody; commonly found during a current or very recent exacerbation that is present in 90% of MSers undergoing Diagnosis.

Oligodendrocyte - (See: Glia Cells - Oligodendrocyte)

Optic Atrophy: Degeneration of the Optic Nerve, due to DeMyelination and loss of Blood Vessels on the Optic Nerve Head, seen as pallor through the Ophthalmoscope.

Optic Nerve: The bundle of Nerve Fibers formed by the light sensitive Retina of the Eye that extends from the Eye and connects to the Brain.

Optic Neuritis: Inflammation of the Optic Nerve (behind the Eye), causing Blurred Vision, Transient or Permanent Loss of Vision and is often associated with Pain in or behind the Eye when Vision deteriorates. Episodes may come and go; but usually reach a peak in a few days and recovery takes from 6 weeks to six months - with or without any particular treatment. Optic Neuritis is very common in many, but not all MSers and usually occurs in only one Eye. It is one of the first diagnosable signs that you may have Multiple Sclerosis. Although Optic Neuritis is very upsetting and scary, it is considered a good indication, of having a milder MS course, when it is the presenting symptom - When the inflammation involves the first part of the Nerve and can be seen at the Optic Disk, usually during the course of an Eye Examination, it is called Optic Papillitis. This may cause colors to appear washed-out or faded and bright lights generally make seeing difficult, even when there are good color contrasts. Wearing yellow tinted sunglasses or adding a light photo-ray tint to your eyeglass prescription will greatly relieve the glare of bright lights.

Organelle (Little Organ): Particles within Cells that are covered with their own membrane. Many different kinds of Organelle occur within Cells, each with a special function.

Oscillopsia: Continuous, Involuntary, and Chaotic Eye movements that result in a Visual Disturbance in which objects appear to be Jumping or Bouncing. (Also See: Nystagmus)

Orthotic: A mechanical appliance such as a Leg brace or Shoe inserts that are specially designed to Control, Correct, or Compensate for impaired limb function. Ovulation (say: ov-yoo-lay-shun) - When the ovaries release an egg, about once each month, as part of the menstrual cycle.

Ovaries: (say: o-var-eez) - Two organs (about the size of an almond or grape), one on each side of the uterus, in the pelvis of a female. The ovaries contain eggs (ova) and make female hormones. When one of the ovaries releases an egg about once each month as part of the menstrual cycle, it is called ovulation.

Over-the-Counter: Over-the-counter medicines are medicines you can buy at a pharmacy or store with out a prescription, or an order from your doctor. Examples include cold medicine, medicines for stomach pain, or pain relievers.


Paralysis: Inability to move a part of the body.

Paraparesis: A weakness but not total paralysis of the lower extremities (legs).

Paresis: Partial or incomplete paralysis of a part of the body.

Paresthesias: (Gr.- para = abnormal, aisthesis = sensation) Sensations of Burning, Prickling, Creeping on the Skin, or "Pins-and-Needles" that develop with damage to a Pain Pathway (Nerve or Axon). Which may or may not be associated with any physical findings on Neurological Examination - Lesions or damage in the Dorsal Columns (Spinal Cord) often register as tingling and numbness, due to irritation of Sensory Nerve fibers, as they die. These sensations range from merely annoying to severe pain. In some cases, even the light touch of clothing, can be painful.

Paroxysmal Symptom: Any one of several symptoms which have a Sudden Onset, apparently in response to some kind of movement or Sensory Stimulation, last for a few moments, and then subside. They are thought to be caused by the short-circuiting of electrical impulses along DeMyelinated Axons.

Pelvic Inflammatory Disease (PID): (say: P-I-D) - A general term for infection of the lining of the uterus, fallopian tubes, or the ovaries. Most cases of PID are caused by bacteria that causes STD's such as chlamydia and gonorrhea. The most common symptoms include abnormal vaginal discharge (fluid), lower stomach pain, and sometimes fever.

Peptides: Short strings (groups) of Amino Acids, which Immune Cells (Leukocytes) use to identify Cells, as belonging to Self or Antigen.

Peripheral Nervous System: All the Nerves and Nerve Cells outside the Central Nervous System.

PeriVentricular Region: The area surrounding the four fluid-filled cavities (Ventricles) within the Brain. MS plaques are commonly found within this region.

Phagocyte: A PolyMorphoNuclear Leukocyte that consumes cellular debris and invading MicroOrganisms. Neutrophils, Dendrites, and Macrophages are Phagocytes or eating cells (phago = "eating", cyte = "cell") - These APCs present Antigens on their cell surfaces that are the chemical remains (Peptide) of the Organism. Antigens presented in this way activate specific responses and destroy the invading Organism.

Phagocytosis: The engulfment, digestion, and subsequent processing of debris or a MicroOrganism by Antigen Presenting Cells.

PhosphoLipids: Are fatty substances that are a major component of Myelin.

Pituitary Gland: (often called the master gland) is located in a small bony cavity at the base of the Brain, it has two Lobes: the Anterior and Posterior Lobes - The Anterior Pituitary is Glandular. A stalk links the Pituitary to the HypoThalamus, which controls release of Pituitary Hormones. The Posterior Pituitary is used to store Hormones until they are needed. Also See: GlucoCorticoid Hormones.

Placebo Effect: The apparently beneficial result of a medication or other therapy that has no proven value or effect in the management of a medical problem. The apparent benefits occur because of an individual's expectation that the therapy will help. Some people respond to the placebo or sham treatment simply because they are convinced that they have been given the real treatment, and may even have a real physical reaction to the placebo.

Plantar Reflex: A Reflex Response obtained by drawing a pointed object along the outer border of the sole of the foot from the Heel to the little Toe. The normal Flexor Response is a bunching and downward movement of the Toes. An upward movement of the big Toe is called an Extensor Response, or Babinski's Sign, which is a sensitive indicator of disease (Spasticity) in the Brain or Spinal Cord.

Plasma: (say: plaz-muh) - The liquid part of blood, which contains nutrients, proteins, minerals and dissolved waste products.

Platelets: (say: playt-lats) - Small cells floating in the blood that play a key role in blood clotting.

Plaque: The Scarring of Neural tissue that develop after DeMyelination and Lesions.

Polycystic Ovarian Syndrome: (say: P-C-O-S) - PCOS is a mild hormonal imbalance that can cause irregular periods, unwanted hair growth, weight gain, and acne. This is a common condition that begins during the teenage years.

Prednisone: A Steroid drug related chemically and therapeutically to the Steroid Hormones normally made in the the Adrenal Glands. Prednisone and other Steroid medications carry significant Long-Term Risks.

Pons: The portion of the BrainStem just Superior to the Medulla Oblongata, is about 2.5cm. in length. It contains the Respiratory Center, which controls the mechanism that permits Outflow of air from the Lungs.

Posterior Column: Bundle of Axons in the Posterior part of the Spinal Cord. Interruption of this column on one side of the Spinal Cord causes loss of Position Sense below the level of the interruption on the Same Side of the body.

Prevalence: The number of all new and old cases of a disease in a defined population at a particular point in time.

Primary/Progressive MS: A clinical course of MS characterized from the beginning by progressive Disability, with no plateaus or remissions or an occasional plateau and very short-lived, minor improvements.

Proactol: Herbal Weight loss supplement made with NeOpuntia. Proactol

Progressive/Relapsing MS: A rare type of MS that shows disease progression (increased Disability) from onset, but with clear, acute relapses, with or without full recovery after each relapse.

Prospective Memory: The ability to remember an event or commitment planned for the future. Thus, a person who agrees to meet or call someone at a given time on the following day, must be able to remember the appointment when the time comes. Both Prospective and Recent Memory are frequently major Cognitive problems for MSers.

Proteins - A group of complex organic compounds, composed of Amino Acids, with defined three-dimensional structures (encoded in DNA) that controls its particular function. Proteins are responsible for all reactions and activities of Cells.

Pseudo-Exacerbation: A temporary aggravation of disease symptoms, resulting from an elevation in body temperature or other stressor (ex. an infection, fatigue, heat, or constipation), that disappears once the stressor is removed. A pseudo-exacerbation involves only pre-existing symptoms (flare-up), rather than new disease activity or progression.

Puberty: (say: pyoo-bur-tee) - The process of developing from a child to sexual maturity, when a person becomes capable of having children. In a girl, puberty includes a growth spurt, development of breasts and hips, growth of body hair, and the beginning of menstruation (having periods).

Pyramidal Tract (CorticoSpinal): One of the major Motor Tracts from the Brain to the Spinal Cord. The Pyramidal System is specialized for making discrete movements, its Axons fibers form the Pyramids of the Medulla Oblongata. It originates in the Cortex of the Frontal Lobe. It communicates directly with Motor Neurons in the Spinal Cord, to activate Fine Motor Control: ex: tying shoelaces, writing, etc. It orchestrates the Motor Response and helps to Specify Body Posture at all levels of the Spinal Cord. It Adjusts Muscle Tone to counter the changing centers of gravity Plaque here causes the symptoms of Spasticity: Muscle Tightness, Ankle Clonus, Flexor Spasms, Exhaustion, Loss Of Muscle Power, and Paralysis


Quadriplegia - The paralysis of both arms and both legs - Quadriplegia and Paraplegia Difference


Recent Memory: The ability to remember events, conversations, content of reading material, or television programs from a short time ago (i.e. an hour or two ago, or last night). MSers with MS-related memory impairment typically experience the greatest difficulty remembering these types of things from the recent past.

Red blood cells: (say: red blud sels) - Small, hemoglobin-filled blood cells that carry oxygen to the body's tissues.

Referred pain: Pain that is felt in another area to the original source of this pain.

Reflex: An involuntary response of the Nervous System to a stimulus, such as the Stretch Reflex, which is elicited by tapping a Tendon with a reflex hammer; or Absent Reflexes can be indicative of Neurological damage, including MS, and are therefore tested during the standard Neurological Exam - An unconscious muscle tightening that is mediated by Anterior Horn Neurons, in the Spinal Cord. Increased muscle tone (tightness, spasticity) is normally an early finding in Multiple Sclerosis.

Reflux: Going in a backward direction.

Relapsing/Remitting MS: A clinical phase having distinct relapses (also called acute attacks or exacerbations), with either full recovery (no disability), or partial recovery and lasting disability. There is no visible disease progression (worsening) between attacks; but stable periods, span and mask, the continuing sub-clinical disease process - Relapsing forms of MS are the most common beginning types, comprising 85% of the total. However, 50% of cases will have progression within 10 - 15 years, and an additional 40% within 25 years of onset; as the disease evolves, into the Secondary/Progressive phase.

Relaxation techniques: These are techniques, or things that you can do, to help you relax. They are often used for reducing stress. Relaxation techniques include meditation (sitting still, breathing slowly and clearing your mind), yoga, deep breathing, and visualization (closing your eyes and seeing a scene that relaxes you, such as a beach or a mountain lake).

Remission: A decrease in the severity or number of MS symptoms and signs, or their temporary disappearance. The opposite of remission is exacerbation.

Remote Memory: The ability to remember people or events from the distant past. MSers tend to experience few if any problems with their remote memory.

ReMyelination: The repair or replacement of damaged Myelin, which usually occurs spontaneously in the early course of MS, but is a very slow process. Early MS damage (Lesion) is repaired (ReMyelinated) by Oligodendrocytes extending new cytoplamic extensions that spiral around (rewrap) Axons, to form new Myelin sections (InterNodes).

Reproductive organs: (say: ree-pro-duck-tiv) - The parts of the body involved in reproduction (producing a baby). In a female, they include the uterus, ovaries, fallopian tubes, and vagina.

Reticular Formation: A vital part of the Autonomic Nervous System, which is scattered like a cloud throughout most of the length of the BrainStem. These nuclei receive Nerves innervating the Face and play an important role in Arousing and Maintaining Consciousness. Visual, or Acoustical Stimuli, and Mental Activities can stimulate this system to maintain Attention and Alertness.

Retrobulbar Neuritis: Inflammation of the second part of the Optic Nerve (behind the Eye), which cannot be seen by an Eye Examination. It is one of the most common beginning symptoms of Multiple Sclerosis; but can also occur as an isolated Neurological Lesion incident, with full recovery of Vision and no further progression to Clinically Definite MS. (Also See: Optic Neuritis)

RetroVirus: A type of Virus named for its ability to convert RNA to DNA and thus use Genetic material to make the proteins it needs to survive and reproduce itself, causing several diseases in the process. Rheumatoid Arthritis (say: roo-muh-toyd arth-rytis) - A painful disease that causes joints, tissues, and sometimes other parts of your body, to swell.

Romberg's Sign: Loss of Position Sense indicated by, the inability to remain immobile (without swaying), while standing with Feet together and Eyes closed. (Also See: Babinski's Sign)

Romberg Test: An examination by a physician during which your positional sense of balance is tested. It entails you standing with feet together, arms outstretched in front, and eyes open, and then closed.


Scanning Speech: Un-natural Speech characterized by Staccato-like Articulation, that sounds clipped because the person unintentionally pauses between syllables and skips some of their sounds.

Sclerosis: Hardening of tissue. In MS, sclerosis is the body's replacement of lost Myelin, around CNS Axons with scar tissue. Early Lesions are usually ReMyelinated and functions return. However, if Astrocytes make Sclerosis (Gliosis), Myelin can NOT be repaired and the damage is permanent.

Scoliosis: (say: sko-lee-oh-sis) - When the spine curves either away from the middle of the body or to the side.

Scotoma: A Gap or Blind Spot in the Visual Field. (Also See: Centrocecal Scotoma)

Secondary/Progressive MS: A clinical course of MS which initially is Relapsing/Remitting and then becomes progressive at a variable rate, possibly with an occasional relapse and minor remission - MS that begins with a pattern of clear-cut relapses and recovery, but becomes steadily progressive over time with continued worsening between occasional acute attacks. (Also See:Types of MS)

Segment, Spinal Cord: One defined portion of the Spinal Cord, which are - Eight Cervical Segments (Neck & Upper Extremities); Twelve Thoracic Segments (Chest); Five Lumbar Segments (Lower Trunk & Lower Extremities); and Five Sacral Segments (Buttocks, Bowel, Bladder and Sexual Function).

Self-esteem: How you feel about yourself - how you feel about who you are, the way you act, and how you look. When a person does not think too highly of themselves, she is said to have low self-esteem.

Sensory: Receptor mechanisms monitoring changes in both external and internal environment and convey this data to the CNS. Such as: Pain, Smell, Taste, Temperature, Vision, Hearing, Touch, and ProprioCeption (Acceleration and Position In Space). This awareness enables the coordination and quick implementation of survival reactions.

Sensory Cortex: The network of Neurons located along the Cerebral Parietal Lobe's surface.

Sensory Input: Stimuli that the Nervous System receives from the external or internal environment: includes Pressure, Taste, Odor, Sound, Light, and Blood pH.

Sensory Neurons: The Cell-Bodies of Axons carrying signals from receptors that transmit information about the environment, to processing centers in the Brain and Spinal Cord. Spinal Cord Neurons processing messages from peripheral receptors are sometimes called Afferent Neurons or InterNeurons.

Sensory Pathways (Afferent): Axons carrying information from organs and tissues to Cortical control centers (Thalamus, Parietal Lobe).

Sequela- A condition following or caused by a previous disease; an after effect of illness.

Sign, Neurologic: An objective physical problem or abnormality identified by a doctor during the Neurological Examination. Neurological signs may differ significantly from the symptoms reported by the patient, because they are identifiable only with specific tests and may cause no noticeable symptoms - Any evidence of malfunction perceived by a physician. (Also See: Babinski's Sign And Romberg's Sign)

SomatoSensory Evoked Potentials: A painless test which records nerve message transmission times within the Brain, in response to repeated electrical shocks, applied to a Peripheral Nerve. Slower response times are typically present in early MS, especially the Nerves of the legs and feet - Normally, the Brain's reaction to such stimuli is almost instantaneous. DeMyelination or a Lesion in the Nerve Pathway causes a delay, so reception time will be significantly slower than normal. (Also See: Evoked Potentials)

Spasticity: CNS damage caused by Multiple Sclerosis, prevents Nerve messages from reaching the Brain's higher control area (Cerebellum); thus it is unable to inhibit the reflex orders (Muscle Contracting) initiated in the Spinal Cord - Muscle groups normally work together, when one is flexed, its opposing muscle is relaxed. MS disrupts this communication causing muscles to needlessly stay tight or contracted. This increased muscle tone is called Spasticity. Increased Muscle Tone - Tightness or Stiff Muscles, usually around a Joint - Increased resistance to movement. It refers to the stiffness that can occur in a Limb, usually in the Leg. Spasticity often accompanies Weakness, but it is possible to have Spasticity without Weakness and to have Weakness without Spasticity - Spasticity tends to occur most frequently in a specific group of muscles that are responsible for maintaining our upright posture, referred to as Anti-Gravity or Postural Muscles. These include the Calf (Gastrocnemius), Thigh (Quadriceps), Buttock (Gluteus Maximus), Groin (Adductor) and occasionally the Back (Erector Spinae) Muscles.

Spina Bifida: (say: spyna bif-id-uh) - A birth defect that stops the bones of the spine from finishing forming right. It can cause legs to be paralyzed (unable to move) and cause loss of control over the bladder.

Spinal Cord: is the communication link between the Brain and the Peripheral Nervous System (PNS) inferior to the head; it integrates incoming Nerve impulses and produces responses through Reflex mechanisms - The cord extends from the Foramen Magnum to the level of the 2nd Lumbar Vertebra. It is composed of Cervical, Thoracic, Lumbar, and Sacral Segments, which are named according to the area of the Vertebra Column from which their Nerves enter and exit - Thirty-one pairs of Spinal Nerves exit the Spinal Cord and pass out of the vertebral column through the InterVertebra Foramia. Nerves to the extremities enter and leave through: The Cervical Enlargement - in the inferior Cervical region corresponds to the location at which Nerves that supply the upper limbs enter or exit the cord The LumboSacral Enlargement - in the inferior Thoracic and superior Lumbar regions is the site at which the Nerves that supply the lower limbs enter or exit - In cross section, the Spinal Cord consists of a central Gray portion and a peripherial White portion. The White Matter consists of Nerve Tracts, and the Gray Matter consists of Nerve Cell Bodies and Dendrites. An Anterior median Fissure and a Posterior median Sulcus are deep clefts partially separating the two halves of the Cord.
Splenium - the rear portion of the Corpus Callosum, above the Pineal Gland.

Steroids (See: GlucoCorticoid Hormones)

Stimulus: Elicits a physiological response.

Subcutaneous: Just beneath the skin

Suppressor T-Lymphocytes: White Blood Cells (Lymphocytes) which inhibit or stop certain Immune activity, and which may be in short supply during a MS exacerbation.

Symptom: Any report of malfunction perceived by a patient. Common symptoms of MS include Visual Problems, Fatigue, Sensory Changes, Weakness or Paralysis of Limbs, Tremor, Lack of Coordination, Poor Balance, Bladder or Bowel Changes, and Cognitive Changes.

Synapse: The specialized junction between Neurons, there is no anatomical continuity between them. Instead, the gap is crossed by, NeuroTransmitters that diffuse across the Synapse completing the connection, from the end branch of a PreSynaptic Axon, to the Dendrite, Cell Body, or Axon of a PostSynaptic Neuron.

Syndrome: A set of symptoms that indicate towards a certain condition, disease or abnormality.


T-Cell: A type of white blood cell (Leukocyte), whose activities are influenced by their development in the Thymus Gland - Are responsible for Cell-Mediated Immune Responses - used to fight viral infections. (See: Lymphocytes) - A white blood cell (Lymphocyte) that dominates the Cellular Immune response to an Antigen.

Tandem Gait: A test of balance and coordination which involves alternately placing the Heel of one Foot directly in front of the Toes of the other Foot.

Thalamus: Most Sensory Input initially projects to the Thalamus where Afferent Neurons synapse with Thalamic Neurons, which send projections from the Thalamus to the Cerebral Cortex. The Thalamus also has other functions, such as influencing Mood and General Body Movements that are associated with Strong Emotions such as Fear or Rage.

Thrombocytes: (say: throm-boh-syts) - Platelets, which are in your blood.

Thymus: A small Gland in the Chest above the Heart. The Thymus influences the behavior of White Blood Cells and other elements of the body's Immune System.

Tic-Douloureux: See Trigeminal Neuralgia.

Titer: A level or strength of a substance such as AntiBodies in Serum.

Tolerance: The T-Cell's inability or diminished sensitivity to an Antigen.

Toxic Shock Syndrome: (say: T-S-S) - A very rare but dangerous illness that affects the whole body. TSS is caused by bacteria that make toxins (poisons) in the body. Tampon use can make it easier for bacteria to enter the body. Symptoms include high fever that comes on suddenly, dizziness, rash, and feelings of confusion.

Tract: A bundle of Axons traveling together. In most cases, the Origin and Destination of Axons in a Tract are quite similar.

Transverse Myelitis: Inflammation in the Spinal Cord interfering with Nerve function below the level of the inflammation. (Also See: MS Hug) - An acute attack of inflammatory DeMyelination that involves a section of the Spinal Cord. Paralysis and Numbness are experienced in the Legs and Trunk below the level of the inflammation. (Also See: Spinal Cord Segment)

Tremor: Either with Intention or Sustention indicates Cerebellar damage (Muscle In-Coordination). Intentional Tremor becomes more shaky, in direct correlation to your increased concentration to reach, grasp, or do something.

Trigeminal Neuralgia (Tic-Douloureux): Pain in the Face that comes on abruptly that sometimes develops with Multiple Sclerosis. Lightening-like, acute pain in the face caused by DeMyelination of Nerve Fibers, where the Trigeminal Nerve's Sensory Root, for that part of the Face enters the BrainStem - Tic (sudden jerk) Douloureux (caused by pain) most commonly strikes inside and outside of the cheek, back across the face towards the ear, and the upper teeth. The Anticonvulsants [Tegretol (Carbamazepine); Dilantin (Phenytoin); Neurontin (Gabapentin)] effectively relieve the pain of Trigeminal Neuralgia.

Tumor Necrosis Factor (TNF): A Cytokine released by activated Macrophages, similar to LymphoToxin that activated T-Cells secrete. It enhances activation of T-Cells, and induces proliferation of T-Cells and B-Cells - TNF also attracts additional Macrophages and Granulocytes to the site. This prompts Macrophage and other Immune Cells, to release tissue-damaging, Oxygen-containing substances and ProstaGlandins to promote Inflammation.


Uhthoff's Syndrome: A metabolic by-product of exercise, or an increase in body temperature causes a Reversible Conduction Block in a DeMyelinated Optic Nerve, resulting in the temporary loss or blurriness of Vision - Uhthoff's Symptom (temporary Visual Loss with exercise), is an indication of Optic Neuritis and a major risk factor for the recurrence of Optic Neuritis and the further development of Multiple Sclerosis.

Urinary Retention - Involuntary accumulation of excessive Urine in the Bladder.

Urinary Tract Infection: (say: yoor-in-ar-ee trakt in-feck-shun or U-T-I) - An infection that happens in the bladder or tube leading to the bladder. It is usually caused by a type of bacteria.

Uterus: (say: yoo-ter-us) - Also called the womb. The uterus is a pear-shaped, hollow organ in a female's pelvis where a baby develops during pregnancy. The uterus is made up of muscle with an inside lining called the endometrium. The endometrium builds up and thickens during the menstrual cycle to prepare for a possible pregnancy each month. But if no pregnancy occurs, the extra tissue and blood are shed during menstruation.

Uveitis: Inflammation within the middle layer of the Eye (the Uvea) between the Sclera and Retina, affecting any of the three parts of the Uvea: The Iris - the colored part of the Eye. The Ciliary Body - behind the Iris, which makes the fluid inside the Eye. The Choroid - a Vascular lining beneath the Retina.


Vagina: (say: vah-jye-na) - Sometimes called the birth canal. The vagina is a muscular passage that leads down from the cervix, (the lower part of the uterus) to the outside of a female's body. During menstruation, menstrual blood flows from the uterus through the cervix and out of the body through the vagina.

Veins: (say: vayns) - Thin-walled blood vessels that receive blood from capillaries and return it to the heart.

Ventricles: The four cavities in the CNS that contain the Vascular membrane (Choroid Plexus) which secrete CerebroSpinal Fluid. There are two Lateral Ventricles (one in each Hemisphere), they connect with the Third Ventricle in the DienCephalon - In the MidBrain, the Cerebral Aqueduct connects with the Fourth Ventricle (located between the Pons, Cerebellum, and Medulla Oblongata). Which joins the Central Canal of the Spinal Cord and the SubArachnoid space which surrounds the Central Nervous System. (Also See: Ventricular System)

Vertigo: A feeling of internal uneasiness, confusion, or light-headiness (passing out). The term Dizzy is commonly confused with Vertigo (a sensation your surroundings are spinning) - While the feeling that you are off-balance, vaguely out-of-sorts, and/or actually spinning (not your surroundings) is Dizziness. DeMyelination within the Cerebellum or its Nerve Pathways, may cause Dizziness. (Also See: Vertigo/Dizziness)

Virus: A living agent, the smallest and simplest form of life, which depends on other living cells, in order to reproduce itself. The first known Virus was discovered in 1898.

Visual Evoked Potentials: A diagnostic technique for recording electrical response times, in the CNS to repeated visual stimuli. This is a very sensitive way of detecting Optic Neuritis - Evoked Potential Tests are able to confirm the presence of a suspected Lesion, and can identify the presence of an unsuspected Lesion (Clinically Silent), which has produced no symptoms. They are extremely useful in diagnosing MS and VEPs are abnormal, in approximately 90% of MS cases.

Vitamins: (say: vy-tuh-mins) - Vitamins and minerals are drugs that replace or fix low levels of important natural substances in your body. You get vitamins and minerals from food. Some types of food have more of these good substances than others. If you need extra vitamins and minerals, you may have to take pills that have them.

Vulva: (say: vul-vuh) - The vulva covers the entrance to the vagina and has five parts: mons pubis, labia, clitoris, urinary tract opening, and vaginal opening.


Wallerian Degeneration: Is Axonal Degeneration without local Inflammation and before local DeMyelination that results from a distal injury to the same Axon. Wallerian Degeneration commonly occurs, sometime after a distant Axonal part has been severed.

White blood cells: (say: white blud sels) - Blood cells that are involved in fighting infection and helping to heal wounds.

White Matter: The common term for Myelin and/or the Medullary Body and consists of: Myelinated Axons, and supporting cells (Astrocytes). The Medullary Body is the Cerebrum's deep interior (includes the Corpus Callosum, surrounds the Basal Ganglia, and parts of the Ventricles) - Various other Nerve Pathways (ie; Cerebral Peduncles, CorticoSpinal Tract, and Medial Fasciculus Longitudinal) interconnect the entire Brain to the Spinal Cord). White Matter constitutes a larger percentage of the Central Nervous System (CNS) than Neurons (Gray Matter) and DeMyelination, damage to Neurons, their Axons, or Myelin cause MS Symptoms.

Related Definitions

Post to Twitter Add to Facebook

Disabled World is an independent disability community established in 2004 to provide disability news and information to people with disabilities, seniors, their family and/or carers. See our homepage for informative news, reviews, sports, stories and how-tos. You can also connect with us on Twitter and Facebook or learn more about Disabled World on our about us page.

Disabled World provides general information only. The materials presented are never meant to substitute for professional medical care by a qualified practitioner, nor should they be construed as such. Financial support is derived from advertisements or referral programs, where indicated. Any 3rd party offering or advertising does not constitute an endorsement.

Cite This Page (APA): Disabled World. (2009, January 11). Definitions and Pronunciation of Medical Terminology. Disabled World. Retrieved January 30, 2023 from

Permalink: <a href="">Definitions and Pronunciation of Medical Terminology</a>