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January 7, 2009
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 Chronic Pain Main Article |  Glossary |  Chronic Pain Index 

Chronic Pain Glossary of Terms

The following are health and medical definitions of terms that appear in the Chronic Pain article.

Abnormal: Not normal. Deviating from the usual structure, position, condition, or behavior. In referring to a growth, abnormal may mean that it is cancerous or premalignant (likely to become cancer ).
See the entire definition of Abnormal

Access: 1. In general, a means of approaching something. 2. In health care, the opportunity or right to receive health care. 3. In dialysis, the point on the body where a needle or catheter is inserted to gain entry to the bloodstream.

Accessory: Additional, extra, supplementary, subsidiary to the main thing. An accessory digestive organ is an organ that helps with digestion but is not part of the digestive tract. The accessory nerve is so-called because it receives an additional (accessory) root from the upper part of the spinal cord. An accessory placenta is an extra placenta separate from the main placenta.

Acetaminophen: A pain reliever and fever reducer. Brand name: Tylenol. The exact mechanism of action of acetaminophen is not known. Acetaminophen relieves pain by elevating the pain threshold (that is, by requiring a greater amount of pain to develop before it is felt by a person). Acetaminophen reduces fever through its action on the heat-regulating center (the "thermostat") of the brain. Generic is available.

Acetylcholine: A key chemical in neurons (nerve cells) that acts as a neurotransmitter and carries information across the synaptic cleft, the space between two nerve cells. Abbreviated ACh.

Acupuncture: The practice of inserting needles into the body to reduce pain or induce anesthesia . More broadly, acupuncture is a family of procedures involving the stimulation of anatomical locations on or in the skin by a variety of techniques. There are a number of different approaches to diagnosis and treatment in American acupuncture that incorporate medical traditions from China, Japan, Korea, and other countries. The most thoroughly studied mechanism of stimulation of acupuncture points employs penetration of the skin by thin, solid, metallic needles, which are manipulated manually or by electrical stimulation.
See the entire definition of Acupuncture

Acute: Of abrupt onset, in reference to a disease. Acute often also connotes an illness that is of short duration, rapidly progressive, and in need of urgent care.
See the entire definition of Acute

Acute pain: Pain that comes on quickly, can be severe, but lasts a relatively short time. As opposed to chronic pain.

Addiction: A chronic relapsing condition characterized by compulsive drug-seeking and abuse and by long-lasting chemical changes in the brain. Addiction is the same irrespective of whether the drug is alcohol, amphetamines, cocaine, heroin, marijuana, or nicotine. Every addictive substance induces pleasant states or relieves distress. Continued use of the addictive substance induces adaptive changes in the brain that lead to tolerance, physical dependence, uncontrollable craving and, all too often, relapse. Dependence is at such a point that stopping is very difficult and causes severe physical and mental reactions from withdrawal. The risk of addiction is in part inherited. Genetic factors, for example, account for about 40% of the risk of alcoholism. The genetic factors predisposing to addiction are not yet fully understood.

Adrenal medulla: The inner portion of adrenal gland. (The outer portion is the adrenal cortex).
See the entire definition of Adrenal medulla

Aging: The process of becoming older, a process that is genetically determined and environmentally modulated.
See the entire definition of Aging

Alcohol: An organic chemical in which one or more hydroxyl (OH) groups are attached to carbon (C) atoms in place of hydrogen (H) atoms. Common alcohols include ethyl alcohol or ethanol (found in alcoholic beverages), methyl alcohol or methanol (can cause blindness) and propyl alcohol or propanol (used as a solvent and antiseptic ). Rubbing alcohol is a mixture of acetone , methyl isobutyl ketone, and ethyl alcohol. In everyday talk, alcohol usually refers to ethanol as, for example, in wine, beer, and liquor. It can cause changes in behavior and be addictive.
See the entire definition of Alcohol

Allergic reaction: The hypersensitive response of the immune system of an allergic individual to a substance.
See the entire definition of Allergic reaction

Allodynia: Pain from stimuli which are not normally painful. The pain may occur other than in the area stimulated. Allodynia means other pain. See: Cutaneous allodynia.

American Medical Association (AMA): The AMA. The AMA's mission statement proclaims:
See the entire definition of American Medical Association back to top

Amputation: Removal of part or all of a body part enclosed by skin. For example, removal of part of a finger or an entire finger would be termed an amputation. Removal of an appendix, on the other hand, would not be termed amputation. A person who has undergone an amputation is called an amputee.
See the entire definition of Amputation

Analgesia: The inability to feel pain while still conscious. From the Greek an-, without + algesis, sense of pain.

Analgesic: A drug that relieves pain. With an effective analgesic, there is an inability to feel pain while still conscious. From the Greek an-, without + algesis, sense of pain.

Anesthesia: Loss of feeling or awareness. A general anesthetic puts the person to sleep. A local anesthetic causes loss of feeling in a part of the body such as a tooth or an area of skin without affecting consciousness. Regional anesthesia numbs a larger part of the body such as a leg or arm, also without affecting consciousness. The term "conduction anesthesia" encompasses both local and regional anesthetic techniques. Many surgical procedures can be done with conduction anesthesia without significant pain. In many situations, such as a C-section, conduction anesthesia is safer and therefore preferable to general anesthesia. However, there are also many types of surgery in which general anesthesia is clearly appropriate.

Angina: Chest pain due to an inadequate supply of oxygen to the heart muscle. The chest pain of angina is typically severe and crushing. There is a feeling just behind the breastbone (the sternum) of pressure and suffocation.
See the entire definition of Angina

Ankylosing: Undergoing ankylosis (stiffening or fusion of a joint).

Ankylosing spondylitis: A type of arthritis that causes chronic inflammation of the spine and the sacroiliac joints. Chronic inflammation in these areas causes pain and stiffness in and around the spine. Over time, chronic spinal inflammation (spondylitis) can lead to a complete cementing together (fusion) of the vertebrae, a process called ankylosis. Ankylosis causes total loss of mobility of the spine.
See the entire definition of Ankylosing spondylitis

Antiviral: An agent that kills a virus or that suppresses its ability to replicate and, hence, inhibits its capability to multiply and reproduce.
See the entire definition of Antiviral

Anxiety: A feeling of apprehension and fear characterized by physical symptoms such as palpitations , sweating, and feelings of stress . Anxiety disorders are serious medical illnesses that affect approximately 19 million American adults. These disorders fill people's lives with overwhelming anxiety and fear. Unlike the relatively mild, brief anxiety caused by a stressful event such as a business presentation or a first date, anxiety disorders are chronic, relentless, and can grow progressively worse if not treated.
See the entire definition of Anxiety

Appendix: A small outpouching from the beginning of the large intestine (the ascending colon ). Formally called the vermiform appendix because it was thought to be wormlike.
See the entire definition of Appendix

Arachnoiditis: Inflammation of the middle layer of membranes covering the brain and spinal cord. Arachnoiditis can occur as a complication of procedures such as myelograms, spinal operations, epidural steroid injections, and injury to the spine.

Artery: A vessel that carries blood high in oxygen content away from the heart to the farthest reaches of the body. Since blood in arteries is usually full of oxygen, the hemoglobin in the red blood cells is oxygenated. The resultant form of hemoglobin (oxyhemoglobin) is what makes arterial blood look bright red.
See the entire definition of Artery

Arthritis: Inflammation of a joint. When joints are inflamed they can develop stiffness, warmth, swelling, redness and pain. There are over 100 types of arthritis. (see osteoarthritis, rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis, lupus, gout, pseudogout).

Aspirin: A good example of a tradename that entered into the language, Aspirin was once the Bayer trademark for acetylsalicylic acid .
See the entire definition of Aspirin

Attention: The ability to focus selectively on a selected stimulus, sustaining that focus and shifting it at will. The ability to concentrate.
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Autoimmune: Pertaining to autoimmunity, a misdirected immune response that occurs when the immune system goes awry and attacks the body itself.
See the entire definition of Autoimmune

Autonomic nervous system: Part of the nervous system that was once thought to be functionally independent of the brain. The autonomic nervous system regulates key functions of the body including the activity of the heart muscle (see below), the smooth muscles (e.g., the muscles of the intestinal tract), and the glands.
See the entire definition of Autonomic nervous system

Back pain: Pain felt in the low or upper back. There are many causes of back pain.
See the entire definition of Back pain

Balance: A biological system that enables us to know where our bodies are in the environment and to maintain a desired position. Normal balance depends on information from the inner ear, other senses (such as sight and touch) and muscle movement.
See the entire definition of Balance

Bell: 1. Bell's palsy.
2. Bell, Charles.

Benign: Not cancer. Not malignant . A benign tumor does not invade surrounding tissue or spread to other parts of the body. A benign tumor may grow but it stays put (in the same place).
See the entire definition of Benign

Benzodiazepines: A class of drugs that act as tranquilizers and are commonly used in the treatment of anxiety. Benzodiazepines can cause drowsiness.

Biofeedback: A method of treatment that uses monitors to feed back to patients physiological information of which they are normally unaware. By watching the monitor, patients can learn by trial and error to adjust their thinking and other mental processes in order to control "involuntary" bodily processes such as blood pressure, temperature, gastrointestinal functioning, and brain wave activity.
See the entire definition of Biofeedback

Blood: The familiar red fluid in the body that contains white and red blood cells, platelets, proteins, and other elements. The blood is transported throughout the body by the circulatory system. Blood functions in two directions: arterial and venous. Arterial blood is the means by which oxygen and nutrients are transported to tissues while venous blood is the means by which carbon dioxide and metabolic by-products are transported to the lungs and kidneys, respectively, for removal from the body.

Blood pressure: The blood pressure is the pressure of the blood within the arteries. It is produced primarily by the contraction of the heart muscle. It's measurement is recorded by two numbers. The first (systolic pressure) is measured after the heart contracts and is highest. The second (diastolic pressure) is measured before the heart contracts and lowest. A blood pressure cuff is used to measure the pressure. Elevation of blood pressure is called "hypertension".

Bone: Bone is the substance that forms the skeleton of the body. It is composed chiefly of calcium phosphate and calcium carbonate . It also serves as a storage area for calcium, playing a large role in calcium balance in the blood.
See the entire definition of Bone

Brain: That part of the central nervous system that is located within the cranium ( skull ). The brain functions as the primary receiver, organizer and distributor of information for the body. It has two (right and left) halves called "hemispheres."
See the entire definition of Brain

Bumps: The raised area of a bump or bruise results from blood leaking from these injured blood vessels into the tissues as well as from the body's response to the injury. A purplish, flat bruise that occurs when blood leaks out into the top layers of skin is referred to as an ecchymosis.
See the entire definition of Bumps

Burn: Damage to the skin or other body parts caused by extreme heat, flame, contact with heated objects, or chemicals. Burn depth is generally categorized as first, second, or third degree. The treatment of burns depends on the depth, area, and location of the burn, as well as additional factors, such as material that may be burned onto or into the skin. Treatment options range from simply applying a cold pack to emergency treatment to skin grafts.
See the entire definition of Burn

Bursitis : Bursitis is inflammation of a bursa. A bursa is a tiny fluid-filled sac that functions as a gliding surface to reduce friction between tissues of the body. The major bursae are located adjacent to the tendons near the large joints, such as the shoulders, elbows, hips, and knees.
See the entire definition of Bursitis back to top

Cancer: An abnormal growth of cells which tend to proliferate in an uncontrolled way and, in some cases, to metastasize (spread).
See the entire definition of Cancer

Cannabis: The botanical name for the plant from which marijuana comes. Its full name is Cannibis sativa. Use of cannabis produces a mild sense of euphoria , as well as impairments in judgment and lengthened response time. Cannabis may be smoked or eaten.
See the entire definition of Cannabis

Capsaicin: A component of certain plants, including cayenne and red pepper, used topically to relieve minor arthritis pain and nerve pain. Capsaicin is in creams such as Arthricare and Zostrix that are applied to the skin . It appears to work by reducing a chemical substance found at nerve endings that is involved in transmitting pain signals to the brain .
See the entire definition of Capsaicin

Cardiac: Having to do with the heart.
See the entire definition of Cardiac

Cardiovascular: The circulatory system comprising the heart and blood vessels which carries nutrients and oxygen to the tissues of the body and removes carbon dioxide and other wastes from them.
See the entire definition of Cardiovascular

Carpal tunnel syndrome: A type of compression neuropathy (nerve damage) caused by compression and irritation of the median nerve in the wrist. The nerve is compressed within the carpal tunnel, a bony canal in the palm side of the wrist that provides passage for the median nerve to the hand. The irritation of the median nerve is specifically due to pressure from the transverse carpal ligament.
See the entire definition of Carpal tunnel syndrome

Cartilage: Firm, rubbery tissue that cushions bones at joints. A more flexible kind of cartilage connects muscles with bones and makes up other parts of the body, such as the larynx and the outside parts of the ears.

Causalgia: Intense burning pain and sensitivity to the slightest vibration or touch, usually in the hand or foot, at a site some distance removed from a wound that has healed. This phenomenon was first described in 1872 by the American neurologist Silas Weir Mitchell (1829-1914).
See the entire definition of Causalgia

Cell: The basic structural and functional unit in people and all living things. Each cell is a small container of chemicals and water wrapped in a membrane .
See the entire definition of Cell

Cervical: Having to do with any kind of neck including the neck on which the head is perched and the neck of the uterus. The word "cervix" in Latin means "neck". That is why cervical vertebrae and cervical cancer involve quite disparate parts of the anatomy joined only by the meaning of the word "cervix".
See the entire definition of Cervical

Chemotherapy : 1. In the original sense, a chemical that binds to and specifically kills microbes or tumor cells. The term chemotherapy was coined in this regard by Paul Ehrlich (1854-1915).
2. In oncology, drug therapy for cancer. Also called "chemo" for short.
See the entire definition of Chemotherapy

Chiropractic: A system of diagnosis and treatment based on the concept that the nervous system coordinates all of the body's functions, and that disease results from a lack of normal nerve function. Chiropractic employs manipulation and adjustment of body structures, such as the spinal column, so that pressure on nerves coming from the spinal cord due to displacement (subluxation) of a vertebral body may be relieved. Practitioners believe that misalignment and nerve pressure can cause problems not only in the local area, but also at some distance from it. Chiropractic treatment appears to be effective for muscle spasms of the back and neck, tension headaches, and some sorts of leg pain. It may or may not be useful for other ailments.
See the entire definition of Chiropractic

Chronic: This important term in medicine comes from the Greek chronos, time and means lasting a long time.
See the entire definition of Chronic

Chronic pain: Pain that persists or progresses over a long period of time. As opposed to acute pain.

Circulatory: Having to do with the circulation, the movement of fluid in a regular or circuitous course. Although the adjective "circulatory" need not necessarily refer to the circulation of the blood, for all practical purposes today it does. A circulatory problem is taken usually to be a problem with the blood circulation, for example with heart failure.
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Clinical: 1. Having to do with the examination and treatment of patients. 2. Applicable to patients. A laboratory test may be of clinical value (of use to patients).
See the entire definition of Clinical

Cluster: In epidemiology, an aggregation of cases of a disease or another health-related condition, such as a cancer or birth defect, closely grouped in time and place. The number of cases in the cluster may or may not exceed the expected number. This is determined by cluster analysis, a set of statistical methods used to analyze clusters.

Cocaine: The most potent stimulant of natural origin, a bitter addictive anesthetic (pain blocker) which is extracted from the leaves of the coca scrub (Erythroxylon coca) indigenous to the Andean highlands of South America.
See the entire definition of Cocaine

Coccygeal: Referring to the coccyx, the small tail-like bone at the bottom of the spine, that is made up of 3-5 (average of 4) rudimentary vertebrae. There is a coccygeal nerve that originates in the spinal cord and emerges at the level of the coccyx.

Coccyx: The small tail-like bone at the bottom of the spine very near to the anus. The coccyx is made up of 3-5 rudimentary vertebrae. It is the lowest part of the spinal column.
See the entire definition of Coccyx

Cognitive: Pertaining to cognition , the process of knowing and, more precisely, the process of being aware, knowing, thinking, learning and judging. The study of cognition touches on the fields of psychology , linguistics, computer science, neuroscience , mathematics, ethology and philosophy.
See the entire definition of Cognitive

Cognitive-behavioral therapy: See: Cognitive therapy.

Colon: The part of the large intestine that runs from the cecum to the rectum as a long hollow tube that serves to remove water from digested food and let the remaining material, solid waste called stool , move through it to the rectum and leave the body through the anus . .
See the entire definition of Colon

Compression: 1. The act of pressing together. As in a compression fracture, nerve compression, or spinal cord compression.
2. To shorten in time. In embryology, there may be compression of development with some stages even omitted.

Condition: The term "condition" has a number of biomedical meanings including the following:

  1. An unhealthy state, such as in "this is a progressive condition."
  2. A state of fitness, such as "getting into condition."
  3. Something that is essential to the occurrence of something else; essentially a "precondition."
  4. As a verb: to cause a change in something so that a response that was previously associated with a certain stimulus becomes associated with another stimulus; to condition a person, as in behavioral conditioning.

Connective tissue: A material made up of fibers forming a framework and support structure for body tissues and organs. Connective tissue surrounds many organs. Cartilage and bone are specialized forms of connective tissue. All connective tissue is derived from mesoderm, the middle germ cell layer in the embryo.

Constipation: Infrequent (and frequently incomplete) bowel movements. The opposite of diarrhea, constipation is commonly caused by irritable bowel syndrome, diverticulosis, and medications (constipation can paradoxically be caused by overuse of laxatives). Colon cancer can narrow the colon and thereby cause constipation. The large bowel (colon) can be visualized by barium enema x-rays, sigmoidoscopy, and colonoscopy. Barring a condition such as cancer, high-fiber diets can frequently relieve the constipation.

Contraction: The tightening and shortening of a muscle.

Coronary artery disease: A major cause of illness and death, coronary artery disease (CAD) begins when hard cholesterol substances (plaques) are deposited within a coronary artery.
See the entire definition of Coronary artery disease

Cortex: The outer portion of an organ.
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Cox-2: Cyclooxygenase-2, a protein acts as an enzyme and specifically catalyzes (speeds) the production of certain chemical messengers called prostaglandins. Some of these messengers are responsible for promoting inflammation. When Cox-2 activity is blocked, inflammation is reduced. Unlike cox-1, cox-2 is active only at the site of inflammation, not in the stomach.

Cranial: 1. Pertaining to the cranium or skull. 2. Toward the head. As opposed to caudad. The eye is cranial to the jaw. For a more complete listing of terms used in medicine for spatial orientation, please see the entry to "Anatomic Orientation Terms".

Cranial nerves: Nerves that emerge from or enter the skull (the cranium), as opposed to the spinal nerves which emerge from the vertebral column. Cranial nerves come directly from the brain through the skull.
See the entire definition of Cranial nerves

Cream: A word with many meanings that, in medicine and pharmacy, refers to a water-soluble preparation applied to the skin. An ointment differs from a cream in that it has an oil base.

Culture: A culture is the propagation of microorganisms in a growth media. Any body tissue or fluid can be evaluated in the laboratory by culture techniques in order to detect and identify infectious processes. Culture techniques also be used to determine sensitivity to antibiotics.

Cut: An area of severed skin. Wash a cut or scrape it with soap and water, and keep it clean and dry. Putting alcohol, hydrogen peroxide, or iodine into a wound can delay healing, and should be avoided. Seek medical care if you think you might need stitches, as delay can increase the rate of wound infection. If the cut results from a puncture wound through the shoe, there is a high risk of infection, and you should see your healthcare professional. Redness, swelling, increased pain, and pus draining from the wound also indicate an infection that requires professional care.

Cuts: Severed skin. Washing a cut or scrape with soap and water and keeping it clean and dry is all that is required to care for most wounds. Putting alcohol hydrogen peroxide, and iodine into a wound can delay healing and should be avoided. Seek medical care early if you think that you might need stitches. Any delay can increase the rate of wound infection. Any puncture wound through tennis shoes has a high risk of infection and should be seen by your healthcare professional. Any redness, swelling, increased pain, or pus draining from the wound may indicate an infection that requires professional care.

Cyclooxygenase-1: See: Cox-1.

Cyclooxygenase-2: See: Cox-2.

Cysts: Cysts are abnormal, closed sac-like structures within a tissue that contain a liquid, gaseous, or semisolid substance. Cysts can occur anywhere in the body and can vary in size. The outer, or capsular, portion of a cyst is termed the cyst wall.

Cytokine: A small protein released by cells that has a specific effect on the interactions between cells, on communications between cells or on the behavior of cells. The cytokines includes the interleukins, lymphokines and cell signal molecules, such as tumor necrosis factor and the interferons, which trigger inflammation and respond to infections.

Decompression: 1. In general, the removal of pressure.
2. In surgery, a procedure to remove pressure on a structure, as in decompression of the spinal cord.
3. The lessening of atmospheric pressure on deep-sea divers returning to the surface, or on persons ascending to great heights.

Depression : An illness that involves the body, mood, and thoughts, that affects the way a person eats and sleeps, the way one feels about oneself, and the way one thinks about things. A depressive disorder is not the same as a passing blue mood. It is not a sign of personal weakness or a condition that can be wished away. People with a depressive disease cannot merely "pull themselves together" and get better. Without treatment, symptoms can last for weeks, months, or years. Appropriate treatment, however, can help most people with depression.
See the entire definition of Depression

Dermatomyositis: A chronic inflammatory disease of skin and muscle which is associated with patches of slightly raised reddish or scaly rash . The rash can be on the bridge of the nose, around the eyes, or on sun-exposed areas of the neck and chest. Classically, however, it is over the knuckles. When the characteristic inflammation of the muscle (myositis) occurs without skin disease, the condition is referred to as polymyositis.
See the entire definition of Dermatomyositis

Diabetes: Refers to diabetes mellitus or, less often, to diabetes insipidus . Diabetes mellitus and diabetes insipidus share the name "diabetes" because they are both conditions characterized by excessive urination (polyuria).
See the entire definition of Diabetes back to top

Diabetic neuropathy: A family of nerve disorders caused by diabetes. Diabetic neuropathies cause numbness and sometimes pain and weakness in the hands, arms, feet, and legs. Neurologic problems in diabetes may occur in every organ system, including the digestive tract, heart, and genitalia. People with diabetes can develop nerve problems at any time, but the longer a person has diabetes, the greater is the risk.
See the entire definition of Diabetic neuropathy

Diagnosis: 1 The nature of a disease ; the identification of an illness. 2 A conclusion or decision reached by diagnosis. The diagnosis is rabies . 3 The identification of any problem. The diagnosis was a plugged IV.
See the entire definition of Diagnosis

Dilate: To stretch or enlarge. It comes from the Latin verb "dilatare" meaning "to enlarge or expand."

Disc: Shortened terminology for an intervertebral disc, a disk-shaped piece of specialized tissue that separates the bones of the spinal column.
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Disease: Illness or sickness often characterized by typical patient problems (symptoms) and physical findings (signs). Disruption sequence: The events that occur when a fetus that is developing normally is subjected to a destructive agent such as the rubella (German measles) virus.

Dorsal: Relating to the back or postterior of a structure. As opposed to the ventral, or front, of the structure. Some of the dorsal surfaces of the body are the back, buttocks, calves, and the knuckle side of the hand.
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Dura: The outermost, toughest, and most fibrous of the three membranes ( meninges ) covering the brain and the spinal cord . Dura is short for dura mater (from the Latin for hard mother). Also called the pachymeninx (singular) or pachymeniges (plural).
See the entire definition of Dura

Dysfunction: Difficult function or abnormal function.
See the entire definition of Dysfunction

Electrocardiogram : A recording of the electrical activity of the heart. An electrocardiogram is a simple, non-invasive procedure. Electrodes are placed on the skin of the chest and connected in a specific order to a machine that, when turned on, measures electrical activity all overaround the heart. Output is usually in the form of a long scroll of paper displaying a printed graph of activity. Newer models output the data directly to a computer and screen, although a print-out may still be made.
See the entire definition of Electrocardiogram

Endogenous: Inside. For example, endogenous cholesterol is cholesterol that is made inside the body and is not in the diet.
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Enzyme: A protein (or protein-based molecule) that speeds up a chemical reaction in a living organism. An enzyme acts as catalyst for specific chemical reactions , converting a specific set of reactants (called substrates) into specific products. Without enzymes, life as we know it would not exist.
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Enzymes: Proteins that act as a catalysts in mediating and speeding a specific chemical reaction .
See the entire definition of Enzymes

Epidural: Outside the dura, the outermost, toughest, and most fibrous of the three membranes (meninges) covering the brain and the spinal cord. An epidural hematoma is a collection of blood beneath the skull but outside the dura.

Essential: 1. Something that cannot be done without.
2. Required in the diet, because the body cannot make it. As in an essential amino acid or an essential fatty acid.
3. Idiopathic. As in essential hypertension. "Essential" is a hallowed term meaning "We don't know the cause."

Estrogen: Estrogen is a female hormone produced by the ovaries. Estrogen deficiency can lead to osteoporosis .
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Extension: The process of straitening or the state of being strait. Extension of the hip and knee joints is necessary to stand up from the sitting position.
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Family: 1. A group of individuals related by blood or marriage or by a feeling of closeness. 2. A biological classification of related plants or animals that is a division below the order and above the genus. 3. A group of genes related in structure and in function that descended from an ancestral gene. 4. A group of gene products similarly related in structure and function and of shared genetic descent. 5. Parents and their children. The most fundamental social group in humans.

Fatigue: A condition characterized by a lessened capacity for work and reduced efficiency of accomplishment, usually accompanied by a feeling of weariness and tiredness. Fatigue can be acute and come on suddenly or chronic and persist.
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FDA: The Food and Drug Administration, an agency within the U.S. Public Health Service, which is a part of the Department of Health and Human Services.
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Feet: The plural of foot, both an anatomic structure and a unit of measure.
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Female: The traditional definition of female was "an individual of the sex that bears young" or "that produces ova or eggs". However, things are not so simple today. Female can be defined by physical appearance, by chromosome constitution (see Female chromosome complement), or by gender identification. Female chromosome complement: The large majority of females have a 46, XX chromosome complement (46 chromosomes including two X chromosomes). A minority of females have other chromosome constitutions such as 45,X (45 chromosomes including only one X chromosome) and 47,XXX (47 chromosomes including three X chromosomes).

Fever : Although a fever technically is any body temperature above the normal of 98.6 degrees F. (37 degrees C.), in practice a person is usually not considered to have a significant fever until the temperature is above 100.4 degrees F (38 degrees C.).
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Fibromyalgia: A syndrome characterized by chronic pain , stiffness, and tenderness of muscles, tendons, and joints without detectable inflammation . Fibromyalgia does not cause body damage or deformity. However, undue fatigue plagues the large majority of patients with fibromyalgia and sleep disorders are common in fibromyalgia.
See the entire definition of Fibromyalgia

fMRI: Functional magnetic resonance imaging.

Food and Drug Administration: The FDA, an agency within the U.S. Public Health Service, which is a part of the Department of Health and Human Services.
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Foot: The end of the leg on which a person normally stands and walks. The foot is an extremely complex anatomic structure made up of 26 bones and 33 joints that must work together with 19 muscles and 107 ligaments to execute highly precise movements. At the same time the foot must be strong to support more than 100,000 pounds of pressure for every mile walked. Even small changes in the foot can unexpectedly undermine its structural integrity and cause pain with every step.
See the entire definition of Foot

Functional magnetic resonance imaging: The use of magnetic resonance imaging (MRI) to learn which regions of the brain are active in a specific function, as in speech. Abbreviated fMRI. See also: Magnetic resonance imaging

Gastrointestinal: Adjective referring collectively to the stomach and small and large intestines.
See the entire definition of Gastrointestinal

Gene: The basic biological unit of heredity . A segment of deoxyribonucleic acid (DNA) needed to contribute to a function.
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Generic: 1. The chemical name of a drug. 2. A term referring to the chemical makeup of a drug rather than to the advertised brand name under which the drug may be sold. 3.A term referring to any drug marketed under its chemical name without advertising.

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Genes: The basic biological units of heredity . Segments of deoxyribonucleic acid (DNA) needed to contribute to a function.
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Genetic: Having to do with genes and genetic information.

Genetics: The scientific study of heredity . Genetics pertains to humans and all other organisms. So, for example, there is human genetics, mouse genetics, fruitfly genetics, etc.
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Geriatrics: The branch of medicine concerned with the diagnosis , treatment and prevention of disease in older people and the problems specific to aging .
See the entire definition of Geriatrics

Glutamate: A form of glutamic acid. See: Glutamic acid.

Gout: Condition characterized by abnormally elevated levels of uric acid in the blood, recurring attacks of joint inflammation (arthritis), deposits of hard lumps of uric acid in and around the joints, and decreased kidney function and kidney stones. Uric acid is a breakdown product of purines, that are part of many foods we eat. The tendency to develop gout and elevated blood uric acid level (hyperuricemia) is often inherited and can be promoted by obesity, weight gain, alcohol intake, high blood pressure, abnormal kidney function, and drugs. The most reliable diagnostic test for gout is the identification of crystals in joints, body fluids and tissues.

Graft: Healthy skin, bone, or other tissue taken from one part of the body to replace diseased or injured tissue removed from another part of the body.
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Headache : A pain in the head with the pain being above the eyes or the ears, behind the head (occipital), or in the back of the upper neck. Headache, like chest pain or back ache, has many causes.
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Health: As officially defined by the World Health Organization, a state of complete physical, mental, and social well-being, not merely the absence of disease or infirmity.

Heart: The muscle that pumps blood received from veins into arteries throughout the body. It is positioned in the chest behind the sternum (breastbone; in front of the trachea, esophagus, and aorta; and above the diaphragm muscle that separates the chest and abdominal cavities. The normal heart is about the size of a closed fist, and weighs about 10.5 ounces. It is cone-shaped, with the point of the cone pointing down to the left. Two-thirds of the heart lies in the left side of the chest with the balance in the right chest.
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Heart attack: The death of heart muscle due to the loss of blood supply. The loss of blood supply is usually caused by a complete blockage of a coronary artery, one of the arteries that supplies blood to the heart muscle. Death of the heart muscle, in turn, causes chest pain and electrical instability of the heart muscle tissue.
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Heart rate: The number of heart beats per unit time, usually per minute. The heart rate is based on the number of contractions of the ventricles (the lower chambers of the heart). The heart rate may be too fast ( tachycardia ) or too slow ( bradycardia ). The pulse is bulge of an artery from the wave of blood coursing through the blood vessel as a result of the heart beat. The pulse is often taken at the wrist to estimate the heart rate.
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Herniated disc: Rupturing of the tissue that separates the vertebral bones of the spinal column.
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Herpes: A family of viruses. Herpes also refers to infection with one of the human herpesviruses, especially herpes simplex types 1 and 2.
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Herpes zoster: Also called shingles, zona, and zoster. The culprit is the varicella-zoster virus. Primary infection with this virus causes chickenpox (varicella). At this time the virus infects nerves (namely, the dorsal root ganglia) where it remains latent (lies low) for years. It can then be reactivated to cause shingles with blisters over the distribution of the affected nerve accompanied by often intense pain and itching.

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Hormone: A chemical substance produced in the body that controls and regulates the activity of certain cells or organs.
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Hypnosis: A part of healing from ancient times. The induction of trance states and the use of therapeutic suggestion were a central feature of the early Greek healing temples, and variations of these techniques were practiced throughout the ancient world.
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Ibuprofen: A non-steroidal anti-inflammatory drug (NSAID) commonly used to treat pain, swelling, and fever. Common brand names for Ibuprofen include Advil, Motrin, and Nuprin.

Imagery: Both a mental process (as in imagining) and a wide variety of procedures used in therapy to encourage changes in attitudes, behavior, or physiological reactions. As a mental process, it is often defined as "any thought representing a sensory quality." It includes, as well as the visual, all the senses - aural, tactile, olfactory, proprioceptive, and kinesthetic.
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Imitrex: Brand name for sumatriptan, a triptan drug for the treatment of migraine.

Immune: Protected against infection. The Latin immunis means free, exempt.

Immune system: A complex system that is responsible for distinguishing us from everything foreign to us, and for protecting us against infections and foreign substances. The immune system works to seek and kill invaders.
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Infection: The growth of a parasitic organism within the body. (A parasitic organism is one that lives on or in another organism and draws its nourishment therefrom.) A person with an infection has another organism (a "germ") growing within him, drawing its nourishment from the person.
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Inflammation: A basic way in which the body reacts to infection , irritation or other injury, the key feature being redness, warmth, swelling and pain . Inflammation is now recognized as a type of nonspecific immune response .
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Injury: Harm or hurt. The term "injury" may be applied in medicine to damage inflicted upon oneself as in a hamstring injury or by an external agent on as in a cold injury. The injury may be accidental or deliberate, as with a needlestick injury. The term "injury" may be synonymous (depending on the context) with a wound or with trauma.

Involuntary: Done other than in accordance with the conscious will of the individual. The opposite of voluntary.
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Ischemia: Inadequate blood supply (circulation) to a local area due to blockage of the blood vessels to the area.

Isolate: A group in which mating is always between members of the group. For example, the Amish.

Jaw: The bones below the mouth (the mandible) and the bone above the mouth just above the mouth (the maxilla). The word jaw comes from the Anglo-Saxon ceowan meaning to chew.
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Joint: A joint is the area where two bones are attached for the purpose of motion of body parts. A joint is usually formed of fibrous connective tissue and cartilage. An articulation or an arthrosis is the same as a joint.
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Kidney: One of a pair of organs located in the right and left side of the abdomen which clear "poisons" from the blood, regulate acid concentration and maintain water balance in the body by excreting urine. The kidneys are part of the urinary tract. The urine then passes through connecting tubes called "ureters" into the bladder. The bladder stores the urine until it is released during urination.


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Knockout: Inactivation of specific genes. Knockouts are often created in laboratory organisms such as yeast or mice so that scientists can study the knockout organism as a model for a particular disease.

Labor: Childbirth, the aptly-named experience of delivering the baby and placenta from the uterus to the vagina to the outside world. There are two stages of labor. During the first stage (called the stage of dilatation), the cervix dilates fully to a diameter of about 10 cm. In the second stage (called the stage of expulsion), the baby moves out through the cervix and vagina to be born.
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Laminectomy: A surgical procedure in which the posterior arch of a vertebra is removed. Laminectomy is done to relieve pressure on the spinal cord or on the nerve roots that emerge from the spinal canal. The procedure may be used to treat a slipped or herniated disk or to treat spinal stenosis.

Leg: In popular usage, the leg extends from the top of the thigh down to the foot. However, in medical terminology, the leg refers to the portion of the lower extremity from the knee to the ankle.
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Leonardo da Vinci: Architect, engineer, inventor, painter and the father of anatomic art. Leonardo da Vinci first became interested when he was asked by a Veronese anatomist named Marc Antonia Della Torre to do the illustrations for a text of anatomy. Della Torre was to do the dissecting and Leonardo the drawings. Della Torre died unexpectedly and Leonardo assumed both tasks. He dissected and drew more than 10 human bodies in the cathedral cellar of the mortuary of Santa Spirito under the secrecy of candlelight, necessitated by the Church's belief in the sanctity of the human body and a papal decree that forbade human dissection. Leonardo recognized that a scientific knowledge of human anatomy could only be gained by dissecting the human body. This was in striking contrast to the pronouncements of Galen and other anatomists. Da Vinci injected the blood vessels and cerebral ventricles with wax for preservation, an anatomical technique still used today. His drawings of the human anatomy have long been considered as unrivaled.

Lethal: Deadly, fatal, capable of causing death, death-dealing. The word "lethal" comes from the Latin "letum" meaning "death or destruction."

Limb: The arm or leg.

Lithium : Lithium carbonate (brand names: Eskalith; Lithobid), a drug used as a mood stabilizer for the treatment of manic/depressive (bipolar) disorder . It prevents or diminishes the intensity of episodes of mania in bipolar patients. Typical symptoms of mania include pressure of speech, motor hyperactivity, reduced need for sleep , flight of ideas, grandiosity, elation, poor judgment, aggressiveness and possibly hostility.
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Liver: An organ in the upper abdomen that aids in digestion and removes waste products and worn-out cells from the blood. The liver is the largest solid organ in the body. The liver weighs about three and a half pounds (1.6 kilograms). It measures about 8 inches (20 cm) horizontally (across) and 6.5 inches (17 cm) vertically (down) and is 4.5 inches (12 cm) thick.


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Low back pain: Pain in the lower back area that can relate to problems with the lumbar spine, the discs between the vertebrae, the ligaments around the spine and discs, the spinal cord and nerves, muscles of the low back, internal organs of the pelvis and abdomen, or the skin covering the lumbar area.

Lumbar: Referring to the 5 lumbar vertebrae which are situated below the thoracic vertebrae and above the sacral vertebrae in the spinal column. The 5 lumbar vertebrae are represented by the symbols L1 through L5. There are correspondingly 5 lumbar nerves.

Lumbar vertebrae: There are 5 lumbar vertebrae. The lumbar vertebrae are situated between the thoracic vertebrae and the sacral vertebrae in the spinal column. The 5 lumbar vertebrae are represented by the symbols L1 through L5.

Lupus: A chronic inflammatory condition caused by an autoimmune disease. An autoimmune disease occurs when the body's tissues are attacked by its own immune system. Patients with lupus have unusual antibodies in their blood that are targeted against their own body tissues.
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Magnetic resonance imaging : A special radiology technique designed to image internal structures of the body using magnetism, radio waves, and a computer to produce the images of body structures. In magnetic resonance imaging (MRI), the scanner is a tube surrounded by a giant circular magnet. The patient is placed on a moveable bed that is inserted into the magnet. The magnet creates a strong magnetic field that aligns the protons of hydrogen atoms, which are then exposed to a beam of radio waves. This spins the various protons of the body, and they produce a faint signal that is detected by the receiver portion of the MRI scanner. A computer processes the receiver information, and an image is produced. The image and resolution is quite detailed and can detect tiny changes of structures within the body, particularly in the soft tissue, brain and spinal cord, abdomen and joints.
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Male: The traditional definition of male was "an individual of the sex that produces sperm" (or some such). However, things are not so simple today. Male can be defined by physical appearance, by chromosome constitution (see Male chromosome complement), or by gender identification.

Mapping: Charting the location of genes on chromosomes.

Marijuana: A very common street and recreational drug that comes from the marijuana plant.
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Massage: The manipulation of muscle and connective tissue to enhance the function of those tissues and promote relaxation and well-being. Therapeutic massage can ease tension and reduce pain. Massage can be a part of physical therapy or practiced on its own. It can also be highly effective for reducing the symptoms of arthritis, back pain, carpal tunnel syndrome, and other disorders of the muscles and/or nervous system.

Medication: 1. A drug or medicine. 2. The administration of a drug or medicine. (Note that "medication" does not have the dangerous double meaning of "drug.")

Medulla: The innermost part. The adrenal medulla is the innermost part of that gland. The renal medulla is the inner part of the kidney. The spinal medulla is the part of the spinal cord that is lodged within the vertebral canal.

Membrane: A very thin layer of tissue that covers a surface.

Methadone: A synthetic opiate. The most common medical use for methadone is as a legal substitute for heroin in treatment programs for drug addiction. It is usually administered to participating addicts daily in the form of a green, tasteless liquid at a drug treatment clinic. See also: Methadone treatment program.

Microvascular: Pertaining to the microvasculature, the portion of the vasculature of the body consisting of the smaller vessels, those with an internal diameter of at most 100 microns. In contrast to macrovascular.

Migraine: Usually, periodic attacks of headaches on one or both sides of the head. These may be accompanied by nausea, vomiting, increased sensitivity of the eyes to light (photophobia), increased sensitivity to sound (phonophobia), dizziness , blurred vision, cognitive disturbances, and other symptoms. Some migraines do not include headache, and migraines may or may not be preceded by an aura.
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Migraine headache: The most common type of vascular headache involving abnormal sensitivity of arteries in the brain to various triggers resulting in rapid changes in the artery size due to spasm (constriction). Other arteries in the brain and scalp then open (dilate), and throbbing pain is perceived in the head. The tendency to migraine is inherited and appears to involve serotonin, a chemical in the brain involved in the transmission of nerve impulses that trigger the release of substances in the blood vessels that in turn cause the pain of the migraine. These nerve impulses cause the flashing lights and other sensory phenomena known as an aura that may accompany a migraine . Not all severe headaches are migraines and not all migraines are severe.
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Mind: That which thinks, reasons, perceives, wills, and feels. The mind now appears in no way separate from the brain. In neuroscience, there is no duality between the mind and body. They are one.

Morphine: A powerful narcotic agent with strong analgesic (painkilling) action and other significant effects on the central nervous system . It is dangerously addicting. Morphine is a naturally occurring member of a large chemical class of compounds called alkaloids.
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Mouth: 1. The upper opening of the digestive tract, beginning with the lips and containing the teeth, gums, and tongue. Foodstuffs are broken down mechanically in the mouth by chewing and saliva is added as a lubricant. Saliva contains amylase, an enzyme that digests starch. 2. Any opening or aperture in the body. The mouth in both senses of the word is also called the os, the Latin word for an opening, or mouth. The o in os is pronounced as in hope. The genitive form of os is oris from which comes the word oral.

MRI: Abbreviation and nickname for magnetic resonance imaging. For more information, see: Magnetic Resonance Imaging; Paul C. Lauterbur; Peter Mansfield.

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Muscle: Muscle is the tissue of the body which primarily functions as a source of power. There are three types of muscle in the body. Muscle which is responsible for moving extremities and external areas of the body is called "skeletal muscle." Heart muscle is called "cardiac muscle." Muscle that is in the walls of arteries and bowel is called "smooth muscle."

Muscular: Having to do with the muscles. Also, endowed with above average muscle development. Muscular system refers to all of the muscles of the body collectively.

Mutation: A permanent change, a structural alteration, in the DNA or RNA . In humans and many other organisms, mutations occur in DNA. However, in retroviruses like HIV , mutations occur in RNA which is the genetic material of retroviruses.
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Myofascial pain syndrome: A condition characterized by chronic pain in the muscle tissues, similar to fibromyalgia . MPS is sometimes the aftermath of injury. Pain medication, anti-inflammatory medication, and therapies aimed at relaxing the muscles tissues (such as massage, chiropracty, and some forms of acupuncture) have been reported as beneficial. Abbreviated MPS.
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Myositis: Inflammation of muscle tissue. There are many causes of myositis, including injury, medications, and diseases.

Narcotic: 1. A drug that causes insensibility or stupor. A narcotic induces narcosis, from the Greek "narke" for "numbness or torpor."
2. A drug such as marijuana which is subject to regulatory restrictions comparable to those for addictive narcotics.

Nausea: Nausea is the urge to vomit. It can be brought by many causes including, systemic illnesses, such as influenza, medications, pain, and inner ear disease.

Neck: The part of the body joining the head to the shoulders. Also, any narrow or constricted part of a bone or organ that joins its parts as, for example, the neck of the femur bone.
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Nerve: A bundle of fibers that uses chemical and electrical signals to transmit sensory and motor information from one body part to another. See: Nervous system.

Nerve block: A procedure in which an anesthetic agent is injected directly near a nerve to block pain. A nerve block is a form of regional anesthesia.
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Nerve cell: See: Neuron.

Neuralgia: Pain along the course of a nerve.
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Neurectomy: The removal of part or all of a nerve.

Neurofibromatosis: A genetic disorder of the nervous system that primarily affects the development and growth of neural (nerve) cell tissues, causes tumors to grow on nerves, and may produce other abnormalities.
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Neurological: Having to do with the nerves or the nervous system.

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Neuropathic pain: Chronic pain resulting from injury to the nervous system. The injury can be to the central nervous system (brain and spinal cord) or the peripheral nervous system (nerves outside the brain and spinal cord). Neuropathic pain can occur after trauma and many diseases such as multiple sclerosis and stroke. It is common and affects more than 2 million people in the US alone. This type of pain is notoriously difficult to treat.

Neuropathy: Any and all disease or malfunction of the nerves.

Neurotransmitter: A chemical that is released from a nerve cell which thereby transmits an impulse from a nerve cell to another nerve, muscle, organ, or other tissue. A neurotransmitter is a messenger of neurologic information from one cell to another.
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Nicotine: An alkaloid (a nitrogen-containing chemical) made by the tobacco plant or produced synthetically. In the plant kingdom, nicotine is not restricted to tobacco but is widespread. The tobacco plant, Nicotiana tabacum, belongs to the nightshade family, which also includes potatoes, tomatoes, eggplant and red peppers. All contain nicotine. However, the concentration of nicotine in those vegetables is far lower than the level in tobacco. Nicotine has powerful pharmacologic effects (including increased heart rate, heart stroke volume, and oxygen consumption by the heart muscle) as well as powerful psychodynamic effects (such as euphoria, increased alertness, and a sense of relaxation). As is now well known, nicotine is also powerfully addictive. When someone becomes habituated to nicotine and then stops using it, they experience the symptoms of withdrawal, including anxiety, irritability, restlessness, shortened attention span and an intense, sometimes irresistible, craving for nicotine.
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NIH: The National Institutes of Health. The NIH is an important U.S. health agency. It is devoted to medical research. Administratively under the Department of Health and Human Services (HHS), the NIH consists of 20-some separate Institutes and Centers. NIH's program activities are represented by these Institutes and Centers.
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NINDS: Stands for the National Institute of Neurological Disorders and Stroke, one of the National Institutes of Health in the U.S., whose mission is to "support and conduct research and research training on the normal structure and function of the nervous system and on the causes, prevention, diagnosis, and treatment of more than 600 nervous system disorders including stroke, epilepsy, multiple sclerosis, Parkinson's disease, head and spinal cord injury, Alzheimer's disease, and brain tumors."

NK cell: See Natural killer cell.

Nursing: 1) Profession concerned with the provision of services essential to the maintenance and restoration of health by attending the needs of sick persons. 2) Feeding a infant at the breast.

Obesity: The state of being well above one's normal weight.
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Objective: In a microscope, the objective (also called the objective lens) is the lens nearest to the object being examined whereas the lens closest to the eye is termed the ocular (the eyepiece).
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Obstruction: Blockage of a passageway. See, for example: Airway obstruction; Intestinal obstruction.

Olfactory: Pertaining to olfaction, the sense of smell.

Operation: Although there are many meanings to the word "operation", in medicine it refers to a surgical procedure.
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Opioid: 1. A synthetic narcotic that resembles the naturally occurring opiates. 2. Any substance that binds to or otherwise affects the opiate receptors on the surface of the cell.
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Opium: An addictive narcotic drug derived from the unripe seedpods of the opium poppy. Preparations of opium were called laudanum. Derivatives of laudanum include paregoric (a drug to treat diarrhea ), morphine and heroin .
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Optic: Having to do with vision.

Organ: A relatively independent part of the body that carries out one or more special functions. The organs of the human body include the eye, ear, heart, lungs, and liver.

Osteoarthritis: A type of arthritis caused by inflammation, breakdown, and eventual loss of cartilage in the joints. Also known as degenerative arthritis.

Oxygen: A colorless, odorless and tasteless gas that makes up about 20% of the air we breathe (and at least half the weight of the entire solid crust of the earth) and which combines with most of the other elements to form oxides. Oxygen is essential to human, animal and plant life.
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Pain: An unpleasant sensation that can range from mild, localized discomfort to agony. Pain has both physical and emotional components. The physical part of pain results from nerve stimulation. Pain may be contained to a discrete area, as in an injury, or it can be more diffuse, as in disorders like fibromyalgia . Pain is mediated by specific nerve fibers that carry the pain impulses to the brain where their conscious appreciation may be modified by many factors.
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Pain management: The process of providing medical care that alleviates or reduces pain. Pain management is an extremely important part of health care, as patients forced to remain in severe pain often become agitated and/or depressed and have poorer treatment outcomes. Mild to moderate pain can usually be treated with analgesic medications, such as aspirin or ibuprofen . For chronic or severe pain, opiates and other narcotics are often used, sometimes in concert with analgesics; with steroids or non-steroidal anti-inflammatory drugs when the pain is related to inflammation; or with anti-depressants, which can potentiate some pain medications without raising the actual dose of the drug, and which affect the brain's perception of pain. Narcotics carry with them a potential for side effects and addiction, so patients and caregivers must weigh the level of pain against these dangers in the pain management process. The risk of addiction is not normally a concern in the care of terminal patients.
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Paralysis: Loss of voluntary movement (motor function). Paralysis that affects only one muscle or limb is partial paralysis, also known as palsy; paralysis of all muscles is total paralysis, as may occur in cases of botulism.

Parasympathetic nervous system: A part of nervous system that serves to slow the heart rate, increase the intestinal and gland activity, and relax the sphincter muscles. The parasympathetic nervous system, together with the sympathetic nervous system (that accelerates the heart rate, constricts blood vessels, and raises blood pressure), constitutes the autonomic nervous system.

Parkinson's disease: See: Parkinson disease.

Pediatric: Pertaining to children.

Peripheral: Situated away from the center, as opposed to centrally located.
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Peripheral nervous system (PNS): That portion of the nervous system that is outside the brain and spinal cord.
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Perspiration: 1) The secretion of fluid by the sweat (sudoriferous) glands. These small, tubular glands are situated within the skin, as well as in the subcutaneous tissue under it. They discharge their fluid through tiny openings in the surface of the skin. Perspiration serves at least two purposes: the removal of waste products such as urea and ammonia, and cooling of the body temperature as sweat evaporates. 2) The transparent, colorless, acidic fluid secreted by the sweat glands. It contains some fatty acids and mineral matter. Adult perspiration gains its characteristic odor from the waste products excreted. Also known as sweat.

Pharmacy: A location where prescription drugs are sold. A pharmacy is, by law, constantly supervised by a licensed pharmacist.

Phenol: 1. A poisonous corrosive compound obtained by the distillation of coal tar that, in dilute solution, is an antimicrobial agent. Also called carbolic acid. 2. A generic term for any compound similar in structure to phenol (an organic compound with one or more hydroxyl groups attached to an aromatic or carbon ring).

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Phrenology: The study of variations in size, shape, and proportion of the cranium. Phrenology was a pseudoscience of the 18th and 19th centuries based on the belief that a person's character could be learned by looking with care at the shape of their head and noting each and every bump and depression in their skull. The individual mental faculties were believed to be contained in neat compartments in the cerebral cortex and the size of these faculties were supposed to be reflected by the configuration of the skull. The best known model of phrenology was that of Gall who marked off the places of twenty-six organs on the head.
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Physical therapy: A branch of rehabilitative health that uses specially designed exercises and equipment to help patients regain or improve their physical abilities. Physical therapists work with many types of patients, from infants born with musculoskeletal birth defects, to adults suffering from sciatica or the after- effects of injury, to elderly post-stroke patients.

Piercing: Using a sharp instrument, usually a needle, to make a temporary or permanent hole through an earlobe or other body part. Humans have practiced piercing for body decoration since prehistoric times. Unless it is performed using a sterile needle (preferably disposable), piercing can carry a risk of infection . A piercing should be kept clean; antibiotic cream may be applied if the area becomes inflamed.
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Placebo: A "sugar pill" or any dummy medication or treatment.
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Placebo effect: Also called the placebo response . A remarkable phenomenon in which a placebo -- a fake treatment, an inactive substance like sugar, distilled water, or saline solution -- can sometimes improve a patient's condition simply because the person has the expectation that it will be helpful. Expectation to plays a potent role in the placebo effect. The more a person believes they are going to benefit from a treatment, the more likely it is that they will experience a benefit.
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Polymyositis : A chronic inflammatory disease of muscle that begins when white blood cells , the immune cells of inflammation, spontaneously invade muscles, especially the muscles closest to the trunk or torso, resulting in sometimes severe muscle pain, tenderness and weakness.
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Positron emission tomography: PET. A highly specialized imaging technique that uses short-lived radioactive substances to produce three-dimensional colored images of those substances functioning within the body. These images are called PET scans and the technique is termed PET scanning.
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Postherpetic neuralgia: Localized pain in the area of involvement of shingles that persists beyond one month.
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Postoperative: After surgery. As opposed to preoperative, before surgery.

Posture: The carriage of the body as a whole, the attitude of the body, or the position of the limbs (the arms and legs).
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Prescription: A physician's order for the preparation and administration of a drug or device for a patient. A prescription has several parts. They include the superscription or heading with the symbol "R" or "Rx", which stands for the word recipe (meaning, in Latin, to take); the inscription, which contains the names and quantities of the ingredients; the subscription or directions for compounding the drug; and the signature which is often preceded by the sign "s" standing for signa (Latin for mark), giving the directions to be marked on the container.

Primary: First or foremost in time or development. The primary teeth (the baby teeth) are those that come first. Primary may also refer to symptoms or a disease to which others are secondary.
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Progressive: Increasing in scope or severity. Advancing. Going forward. In medicine, a disease that is progressive is going from bad to worse.
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Protein: A large molecule composed of one or more chains of amino acids in a specific order determined by the base sequence of nucleotides in the DNA coding for the protein.
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Proteins: Large molecules composed of one or more chains of amino acids in a specific order determined by the base sequence of nucleotides in the DNA coding for the protein.
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Psychology: The study of the mind and mental processes, especially in relation to behavior. There are a number of fields of psychology. Clinical psychology is concerned with diagnosing and treating disorders of the brain, emotional disturbances, and behavior problems. Child psychology is the study of the mental and emotional development of children and is part of developmental psychology, the study of changes in behavior that occur through the life span. Cognitive psychology deals with how the human mind receives and interprets impressions and ideas. Social psychology looks at how the actions of others influence the behavior of an individual.

Public health: The approach to medicine that is concerned with the health of the community as a whole. Public health is community health. It has been said that: "Health care is vital to all of us some of the time, but public health is vital to all of us all of the time."
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Pulse: The rhythmic contraction and expansion of an artery due to the surge of blood from the beat of the heart. The pulse is most often measured by feeling the arteries of the wrist. There is also a pulse, although far weaker, in veins.

Quackery: Deliberate misrepresentation of the ability of a substance or device for the prevention or treatment of disease. We may think that the day of patent medicines is gone but look around you and you will see them still. They appeal to our desire to believe that every disease is curable or at least treatable. Quackery also applies to persons who pretend to be able to diagnose or heal people but are unqualified and incompetent.

Radiculopathy: Any disease of the spinal nerve roots and spinal nerves. It is synonymous with radiculitis.
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Range: In medicine and statistics, the difference between the lowest and highest numerical values. For example, if five premature infants are born weighing two, three, four, four, and five pounds respectively, the range of their birth weights is two to five pounds.

Receptor: 1. In cell biology, a structure on the surface of a cell (or inside a cell) that selectively receives and binds a specific substance. There are many receptors. There is a receptor for ( insulin ; there is a receptor for low-density lipoproteins ( LDL ); etc. To take an example, the receptor for substance P, a molecule that acts as a messenger for the sensation of pain , is a unique harbor on the cell surface where substance P docks. Without this receptor, substance P cannot dock and cannot deliver its message of pain. Variant forms of nuclear hormone receptors mediate processes such as cholesterol metabolism and fatty acid production. Some hormone receptors are implicated in diseases such as diabetes and certain types of cancer. A receptor called PXR appears to jump-start the body's response to unfamiliar chemicals and may be involved in drug-drug interactions.
2. In neurology, a terminal of a sensory nerve that receives and responds to stimuli.
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Recurrent: Back again. A recurrent fever is a fever that has returned after an intermission: a recrudescent fever.

Reflex: A reaction that is involuntary. The corneal reflex is the blink that occurs with irritation of the eye. The nasal reflex is a sneeze.
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Rehabilitation: The process of restoration of skills by a person who has had an illness or injury so as to regain maximum self-sufficiency and function in a normal or as near normal manner as possible. For example, rehabilitation after a stroke may help the patient walk again and speak clearly again.
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Respiratory: Having to do with respiration, the exchange of oxygen and carbon dioxide. From the Latin re- (again) + spirare (to breathe) = to breathe again.

Respiratory system: The organs that are involved in breathing. These include the nose, throat, larynx, trachea, bronchi, and lungs.

Rest: 1. Repose. Relaxation.
2. A fragment of embryonic tissue that has been retained after the period of embryonic development. Also called an embryonic rest.

Rheumatoid arthritis : An autoimmune disease which causes chronic inflammation of the joints, the tissue around the joints, as well as other organs in the body. Autoimmune diseases occur when the body tissues are mistakenly attacked by its own immune system. The immune system is a complex organization of cells and antibodies designed normally to "seek and destroy" invaders of the body, particularly infections. Patients with these diseases have antibodies in their blood which target their own body tissues, where they can be associated with inflammation. Because it can affect multiple other organs of the body, rheumatoid arthritis is referred to as a systemic illness and is sometimes called rheumatoid disease. While rheumatoid arthritis is a chronic illness (meaning it can last for years) patients may experience long periods without symptoms.
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Rupture: A break or tear in any organ (such as the spleen) or soft tissue (such as the achilles tendon). Rupture of the appendix is more likely among uninsured and minority children when they develop appendicitis.

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Sacral: Referring to the sacrum, the 5 vertebral bones situated between the lumbar vertebrae and the coccyx (the lowest segment of the vertebral column). The 5 sacral vertebrae are represented by the symbols S1 through S5. There are correspondingly 5 sacral nerves. The sacral vertebrae are normally fused to form the sacrum.

Sacrum: The large heavy bone at the base of the spine, which is made up of fused sacral vertebrae. The sacrum is located in the vertebral column, between the lumbar vertebrae and the coccyx. It is roughly triangular in shape and makes up the back wall of the pelvis. The female sacrum is wider and less curved than the male.
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Saline: Relating to salt. As an adjective, "saline" means "salty, containing salt." As a noun "saline" is a salt solution, often adjusted to the normal salinity of the human body.
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Sciatic nerve: The largest nerve in the body, the sciatic nerve begins from nerve roots in the lumbar part of the spinal cord (in the low back) and extends through the buttock area to send nerve endings down to the legs.
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Sciatica : Pain resulting from irritation of the sciatic nerve, typically felt from the low back to behind the thigh and radiating down below the knee. While sciatica can result from a herniated disc directly pressing on the nerve, any cause of irritation or inflammation of this nerve can reproduce the painful symptoms of sciatica. Diagnosis is by observation of symptoms, physical and nerve testing, and sometimes by X-ray or MRI if a herniated disk is suspected.
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Sclerosis: Localized hardening of skin.

Section: 1) In anatomy, a slice of tissue. A biopsy obtained by surgery is usually sectioned (sliced), and these sections are inspected under a microscope. 2) In obstetrics, short for Caesarian section. 3) In surgery, the division of tissue during an operation.

Sedative: A drug that calms a patient down, easing agitation and permitting sleep. Sedatives generally work by modulating signals within the central nervous system. These sedatives can dangerously depress important signals needed to maintain heart and lung function if they are misused or accidentally combined, as in the case of combining prescription sedatives with alcohol. Most sedatives also have addictive potential. For these reasons, sedatives should be used under supervision, and only as needed.

Seizure: Uncontrolled electrical activity in the brain, which may produce a physical convulsion, minor physical signs, thought disturbances, or a combination of symptoms.
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Seizure disorders: One of a great many medical conditions that are characterized by episodes of uncontrolled electrical activity in the brain (seizures). Some seizure disorders are hereditary, but others are caused by birth defects or environmental hazards, such as lead poisoning. Seizure disorders are more likely to develop in patients who have other neurological disorders, psychiatric conditions, or immune-system problems. In some cases, uncontrolled seizures can cause brain damage, lowered intelligence, and permanent mental and physical impairment. Diagnosis is by observation, neurological examination, electroencephalogram (EEG), and in some cases more advanced brain imaging techniques. Treatment is usually by medication, although in difficult cases a special diet or brain surgery may be tried.
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Sensation: In medicine and physiology , sensation refers to the registration of an incoming ( afferent ) nerve impulse in that part of the brain called the sensorium , which is capable of such perception. Therefore, the awareness of a stimulus as a result of its perception by sensory receptors. (Sensory is here synonymous with sensation.)
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Sense: In biology and medicine, the faculty of sensory reception. The ability to convey specific types of external or internal stimuli to the brain and perceive them. Sensory reception occurs through a process known as transduction in which stimuli are converted into nerve impulses which are relayed to the brain.
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Sensitivity: 1. In psychology, the quality of being sensitive. As, for example, sensitivity training, training in small groups to develop a sensitive awareness and understanding of oneself and of ones relationships with others. 2. In disease epidemiology, the ability of a system to detect epidemics and other changes in disease occurrence. 3. In screening for a disease, the proportion of persons with the disease who are correctly identified by a screening test. 4. In the definition of a disease, the proportion of persons with the disease who are correctly identified by defined criteria.

Sensory: Relating to sensation , to the perception of a stimulus and the voyage made by incoming ( afferent ) nerve impulses from the sense organs to the nerve centers.
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Serotonin: A hormone , also called 5-hydroxytryptamine , in the pineal gland , blood platelets, the digestive tract, and the brain. Serotonin acts both as a chemical messenger that transmits nerve signals between nerve cells and that causes blood vessels to narrow.
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Shingles: An acute infection caused by the herpes zoster virus, the same virus as causes chickenpox. Shingles is most common after the age of 50 and the risk rises with advancing age. Shingles occurs because of exposure to chickenpox or reactivation of the herpes zoster virus. The virus remains latent (dormant) in nerve roots for many years following chickenpox.
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Shock: In medicine, shock is a critical condition brought on by a sudden drop in blood flow through the body. There is failure of the circulatory system to maintain adequate blood flow. This sharply curtails the delivery of oxygen and nutrients to vital organs. It also compromises the kidney and so curtails the removal of wastes from the body. Shock can be due to a number of different mechanisms including not enough blood volume (hypovolemic shock) and not enough output of blood by the heart (cardiogenic shock). The signs and symptoms of shock include low blood pressure (hypotension), overbreathing (hyperventilation), a weak rapid pulse, cold clammy grayish-bluish (cyanotic) skin, decreased urine flow (oliguria), and mental changes (a sense of great anxiety and foreboding, confusion and, sometimes, combativeness).
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Side effects: Problems that occur when treatment goes beyond the desired effect. Or problems that occur in addition to the desired therapeutic effect.
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Skin: The skin is the body's outer covering. It protects us against heat and light, injury, and infection. It regulates body temperature and stores water, fat, and vitamin D. Weighing about 6 pounds, the skin is the body's largest organ. It is made up of two main layers; the outer epidermis and the inner dermis.


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Sleep : The body's rest cycle.
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Spasm: A brief, automatic jerking movement. A muscle spasm can be quite painful, with the muscle clenching tightly. A spasm of the coronary artery can cause angina. Spasms in various types of tissue may be caused by stress, medication, over-exercise, or other factors.

Spasticity: A state of increased tone of a muscle (and an increase in the deep tendon reflexes). For example, with spasticity of the legs (spastic paraplegia) there is an increase in tone of the leg muscles so they feel tight and rigid and the knee jerk reflex is exaggerated.
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Spinal cord: The major column of nerve tissue that is connected to the brain and lies within the vertebral canal and from which the spinal nerves emerge. Thirty-one pairs of spinal nerves originate in the spinal cord: 8 cervical , 12 thoracic , 5 lumbar, 5 sacral, and 1 coccygeal. The spinal cord and the brain constitute the central nervous system ( CNS ). The spinal cord consists of nerve fibers that transmit impulses to and from the brain. Like the brain, the spinal cord is covered by three connective-tissue envelopes called the meninges . The space between the outer and middle envelopes is filled with cerebrospinal fluid ( CSF ), a clear colorless fluid that cushions the spinal cord against jarring shock. Also known simply as the cord.
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Spinal fusion: A surgical procedure in which two or more of the vertebrae in the spine are united together so that motion no longer occurs between them.
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Spinal stenosis: Narrowing of the spaces in the spine, resulting in compression of the nerve roots or spinal cord by bony spurs or soft tissues, such as disks, in the spinal canal. This occurs most often in the lumbar spine (in the low back) but also occurs in the cervical spine (in the neck) and less often in the thoracic spine (in the upper back).
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Spine: 1) The column of bone known as the vertebral column, which surrounds and protects the spinal cord. The spine can be categorized according to level of the body: i.e., cervical spine (neck), thoracic spine (upper and middle back), and lumbar spine (lower back). See also vertebral column. 2) Any short prominence of bone. The spines of the vertebrae protrude at the base of the back of the neck and in the middle of the back. These spines protect the spinal cord from injury from behind.

Spondylitis: Inflammation of one or more of the vertebrae of the spine. Diffuse inflammation of the spine is seen in the disease ankylosing spondylitis . Localized spondylitis is seen with infections of a certain area of the spine, such as in Pott's disease.
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Spondylolisthesis: Forward movement of one of the building blocks ( vertebrae ) of the spine in relation to an adjacent vertebra .
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Sprain: An injury to a ligament that results from overuse or trauma. Sprains occurs when there is a stretch or tear in one or more ligaments, slightly elastic bands of tissue that keep the bones in place while permitting movement at a joint. The treatment of a sprain involves applying ice packs, resting and elevating the involved joint, and using anti-inflammatory medications. Depending on the severity and location of the sprain, support bracing can help. Local cortisone injections are sometimes given for persistent inflammation. Activity may be resumed gradually. Ice application after activity can reduce or prevent recurrent inflammation. Occasionally, supportive bracing can prevent reinjury. In severe sprains, orthopedic surgical repair may be performed.

Stenosis: A narrowing, as in:

  • aortic stenosis (narrowing of the aortic valve of the heart),
  • pulmonary stenosis (narrowing of the pulmonary valve of the heart),
  • pyloric stenosis (narrowing of the outlet of the stomach), and
  • spinal stenosis (narrowing of the vertebral canal).

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Stomach: 1. The sac-shaped digestive organ that is located in the upper abdomen, under the ribs. The upper part of the stomach connects to the esophagus, and the lower part leads into the small intestine.
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Strain: 1. An injury to a tendon or muscle resulting from overuse or trauma. 2. A hereditary tendency that originated from a common ancestor. 3. To exert maximum effort. 4. To filter.

Stress: Forces from the outside world impinging on the individual. Stress is a normal part of life that can help us learn and grow. Conversely, stress can cause us significant problems.
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Stroke : The sudden death of some brain cells due to a lack of oxygen when the blood flow to the brain is impaired by blockage or rupture of an artery to the brain. A stroke is also called a cerebrovascular accident or, for short, a CVA.
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Substance: 1. Material with particular features, as a