Documents for "Medicine":

• abortion expulsion of the products of conception before the embryo or fetus is viable. Any interruption of human pregnancy prior to the 28th week is known as abortion. The term spontaneous abortion, or...

• acupuncture technique of traditional Chinese medicine, in which a number of very fine metal needles are inserted into the skin at specially designated points. For thousands of years acupuncture has been used,...

• aerospace medicine see aviation medicine ; space medicine.

• allograft see transplantation, medical.

• alternative medicine the treatment and prevention of disease by techniques that are regarded by modern Western medicine as scientifically unproven or unorthodox. The term alternative medicine can encompass a wide range of therapies, including chiropractic , homeopathy , acupuncture , herbal medicine , meditation, biofeedback , massage therapy, and various "new age" therapies such as guided imagery and naturopathy. Although many alternative therapies have long been widely employed in the treatment of disease, the scientifically oriented modern medical...

• amniocentesis diagnostic procedure in which a sample of the amniotic fluid surrounding a fetus is removed from the uterus by means of a fine needle inserted through the abdomen of the pregnant woman (see pregnancy ). The procedure can be done in a hospital or in a doctor's office. Ultrasound is used to determine the location of the fetus during the procedure. Fetal cells in the fluid can be grown in the laboratory and studied to detect the presence of certain genetic disorders (e.g., Down syndrome , Tay-Sachs disease ) or physical abnormalities (e.g., anencephaly, or incomplete development of the brain). The sample also can be examined to determine the gender of the fetus and has been used to preselect the sex...

• amputation removal of all or part of a limb or other body part. Although amputation has been practiced for centuries, the development of sophisticated techniques for treatment and prevention of infection has...

• anesthesia [Gr.,=insensibility], loss of sensation, especially that of pain , induced by drugs, especially as a means of facilitating safe surgical procedures. Early modern medical anesthesia dates to experiments...

• anesthesiology branch of medicine concerned primarily with procedures for rendering patients insensitive to pain, and for supporting life systems under the strains of anesthesia and surgery. The anesthesiologist...

• angioplasty any surgical repair of a blood vessel, especially balloon angioplasty or percutaneous transluminal coronary angioplasty, a treatment of coronary artery disease. In balloon angioplasty a balloon-tipped catheter is inserted through the skin into a blood vessel and maneuvered to the clogged portion of the artery. There it is threaded into the blockage and...

• apheresis or hemapheresis , any procedure in which blood is drawn from a donor or patient and a component (platelets, plasma , or white blood cells) is separated out, the remaining blood components being returned to the body. Apheresis allows the donor's blood volume to replenish itself much more quickly than whole blood...

• artificial heart see heart, artificial.

• artificial kidney see kidney, artificial.

• artificial life support systems that use medical technology to aid, support, or replace a vital function of the body that has been seriously damaged. Such techniques include artificial pacemakers , internal defibrillators , dialysis machines (see kidney, artificial ), and respirators. The use of life-support systems to prolong the life of a patient who has suffered apparently irreversible damage to a vital organ system may raise such ethical issues as the...

• artificial limb mechanical replacement for a missing limb. An artificial limb, called a prosthesis, must be light and flexible to permit easy movement, but must also be sufficiently sturdy to support the weight of...

• artificial respiration any measure that causes air to flow in and out of a person's lungs when natural breathing is inadequate or ceases, as in respiratory paralysis, drowning, electric shock, choking, gas or smoke...

• asepsis see antiseptic.

• autograft see transplantation, medical.

• balloon angioplasty see under angioplasty.

• Bellevue Hospital municipal hospital, in New York City. America's oldest public hospital, Bellevue developed from a "Publick Workhouse and House of Correction" commissioned in 1734. The establishment changed sites several times before 1811, when the site upon which it now stands was purchased. In 1860 the Bellevue Hospital Medical College, the first of...

• bioethics in philosophy, a branch of ethics concerned with issues surrounding health care and the biological sciences. These issues include the morality of abortion , euthanasia , in vitro fertilization , and organ transplants (see transplantation, medical ). In the 1970s bioethics emerged as a discipline with its own experts, often professional philosophers, who developed university courses on the subject. Many hospitals now employ experts on...

• biofeedback method for learning to increase one's ability to control biological responses, such as blood pressure, muscle tension, and heart rate. Sophisticated instruments are often used to measure...

• biopsy examination of cells or tissues removed from a living organism. Excised material may be studied in order to diagnose disease or to confirm findings of normality. Preparatory techniques depend on...

• birth control practice of contraception for the purpose of limiting reproduction.

• blood bank site or mobile unit for collecting, processing, typing, and storing whole blood , blood plasma and other blood constituents. Most hospitals maintain their own blood reserves, and the American Red Cross provides a nationwide collection and distribution service. The Red Cross...

• blood count method for determining the number of red (erythrocytes) and white (leukocytes) blood cells in a certain volume of blood. This test can be used as a preliminary step in diagnosing some diseases...

• blood substitute substance that mimics the function of blood. Blood substitutes typically concentrate only on reproducing the function of hemoglobin , the molecule that carries oxygen through the body, and do not attempt to replicate the blood's other functions. Blood donated by humans must be refrigerated, can be contaminated by such diseases as AIDS and hepatitis , and is often in short supply. Designers of blood substitutes hope to eliminate these problems and develop genetically engineered or chemical products that will be tolerated by people of all blood...

• blood test examination of blood routinely or as an aid in diagnosing a suspected disease. Tests may be performed on whole blood or on the plasma portion only. Blood typing identifies the proteins at specific sites on red blood...

• blood transfusion transfer of blood from one person to another, or from one animal to another of the same species. Transfusions are performed to replace a substantial loss of blood and as supportive treatment in...

• bloodletting also called bleeding, practice of drawing blood from the body in the treatment of disease. General bloodletting consists of the abstraction of blood by incision into an artery (arteriotomy) or vein...

• Blue Cross plans see health insurance.

• bone marrow transplant see bone marrow.

• breast implant saline- or silicone-filled prosthesis used after mastectomy as a part of the breast reconstruction process or used cosmetically to augment small breasts. An implant consists of a fluid-filled, malleable pouch that is designed to mimic to the look and feel...

• bronchoscope long, tubular instrument with a light at the tip that is inserted through the windpipe and bronchial tubes to examine these structures. By passing other instruments through it, foreign bodies and...

• caesarean section see cesarean section.

• cardiopulmonary resuscitation (CPR), emergency procedure used to treat victims of cardiac and respiratory arrest. CPR can be done in a hospital with drugs and special equipment or as a first-aid technique. In either case it is...

• CAT scan [ c omputerized a xial t omography], X-ray technique that allows relatively safe, painless, and rapid diagnosis in previously inaccessible areas of the body; also called CT scan. An X-ray tube, rotating around a specific area of the body,...

• cautery searing or destruction of living animal tissue by use of heat or caustic chemicals. In the past, cauterization of open wounds, even those following amputation of a limb, was performed with hot...

• cesarean section delivery of an infant by surgical removal from the uterus through an abdominal incision. The operation is of ancient origin: indeed, the name derives from the legend that Julius Caesar was born in...

• chiropody see podiatry.

• chiropractic [Gr.,=doing by hand], medical practice based on the theory that all disease results from a disruption of the functions of the nerves. The principal source of interference is thought to be...

• chorionic villus sampling (CVS) or chorionic villus biopsy (CVB) , diagnostic procedure in which a sample of chorionic villi from the developing placenta is removed from the uterus of a pregnant woman (see pregnancy ) using a fine needle inserted through the abdomen or a thin plastic catheter inserted into the vagina and through the cervix. Chorionic villi are fingerlike projections of a membrane (the chorion)...

• circumcision operation to remove the foreskin covering the glans of the penis. It dates back to prehistoric times and was widespread throughout the Middle East as a religious rite before it was introduced...

• clinic name for an institution providing medical diagnosis and treatment for ambulatory patients. The forerunner of the modern clinic was the dispensary, which dispensed free drugs and served only those...

• computerized axial tomography see CAT scan.

• contact lens thin plastic lens worn between the eye and eyelid that may be used instead of eyeglasses. Actors, models, and others wear them for appearance, and athletes use them for safety and convenience...

• contraception see birth control.

• cosmetic surgery plastic surgery for cosmetic purposes, such as the improvement of the appearance of the face by removing wrinkles or reshaping the nose.

• cryosurgery bloodless surgical technique using a supercooled probe to destroy diseased or superfluous tissue. Liquid nitrogen circulating through the instrument cools it to temperatures as low as -196°C...

• CT scan see CAT scan.

• defibrillator device that delivers an electrical shock to the heart in order to stop certain forms of rapid heart rhythm disturbances ( arrhythmias ). The shock changes a fibrillation to an organized rhythm or changes a very rapid and ineffective cardiac rhythm to a slower, more effective one. In a typical hospital defibrillator, voltage stored...

• dentistry treatment and care of the teeth and associated oral structures. Dentistry is mainly concerned with tooth decay, disease of the supporting structures, such as the gums, and faulty positioning of the teeth. Like medicine and...

• denture artificial replacement for natural teeth and surrounding tissue. Dentures are classified as partial or complete. The former are removable and maintained by clasps, or are fixed bridges with crowns...

• dermatology branch of medicine concerned with diagnosis and treatment of diseases and disorders of the skin. Dermatologists also study the structure and function of the skin, and the relationship between skin pathologies and malfunctions of other organs of the body. Dermatology often overlaps the...

• dispensary see clinic.

• Doctrine of Signatures the concept that the key to humanity's use of various plants was indicated by the form of the plant. The red sap of the bloodroot ( Sanguinaria canadensis ), for instance, was believed to cure diseases...

• EEG see electroencephalography.

• EKG see electrocardiography.

• electric shock effect of the passage of a current of electricity through the body. Fatality may result from shocks of from 1 to 2 amperes and 500 to 1,000 volts. However, the effect of electric shock on the body...

• electrocardiography science of recording and interpreting the electrical activity that precedes and is a measure of the action of heart muscles. Since 1887, when Augustus Waller demonstrated the possibility of measuring such action, physicians and physiologists have recorded it in order to study the heart's normal behavior and to...

• electroencephalography science of recording and analyzing the electrical activity of the brain. Electrodes, placed on or just under the scalp, are linked to an electroencephalograph, which is an amplifier connected to a mechanism that converts electrical impulses into the vertical movement...

• electrolysis, cosmetic method of permanently removing superfluous or unwanted hair. A fine needle is inserted into the hair follicle; the application of an electric current through the needle destroys the hair root, or...

• embryo biopsy or preimplantation genetic diagnosis, diagnostic procedure, used in genetic screening , in which a single cell is removed from an embryo two or three days after it has been conceived through in...

• endodontics see dentistry.

• endoscope any instrument used to look inside the body. Usually consisting of a fiber-optic tube attached to a viewing device, endoscopes are used to explore and biopsy such areas as the colon and the bronchi...

• epidemiology field of medicine concerned with the study of epidemics , outbreaks of disease that affect large numbers of people. Epidemiologists, using sophisticated statistical analyses, field investigations, and complex laboratory techniques, investigate the cause...

• euthanasia either painlessly putting to death or failing to prevent death from natural causes in cases of terminal illness or irreversible coma. The term comes from the Greek expression for "good death." Technological advances in medicine have made it possible to prolong life in patients with no hope of recovery, and the term negative euthanasia has arisen to classify the practice of withholding or withdrawing extraordinary means (e.g., intravenous feeding, respirators, and artificial kidney machines) to preserve life. Accordingly, the term positive euthanasia has come to refer to actions that actively cause death. The term passive euthanasia is used when certain common methods of treatment, such as antibiotics, drugs, or surgery, are withheld or a large quantity of needed but ultimately lethal pain medication is supplied. By the end of...

• exercise see physical fitness.

• eye bank site for the collection, processing, and assignment of donated eyes. A donor's eyes are removed as soon as possible after death, sealed in a sterile container, and sent to the eye bank. There they are microscopically examined for corneal damage and then shipped to...

• eyeglasses or spectacles, instrument or device for aiding and correcting defective sight. Eyeglasses usually consist of a pair of lenses mounted in a frame to hold them in position before the eyes. The first device of this kind was probably invented by Roger Bacon in the 13th cent. although similar devices are believed to have...

• female genital mutilation see circumcision.

• fetal cell therapy see fetal tissue implant.

• fetal tissue implant or fetal cell therapy, implantation of tissue from a fetus into a patient. In experimental procedures, fetal brain tissue has been implanted in the brains of patients with Parkinson's disease so that the fetal tissue will supply chemicals lacking in the diseased brain, but such therapy failed to show significant benefits in a controlled study. Because fetal cell therapy uses tissue from...

• first aid immediate and temporary treatment of a victim of sudden illness or injury while awaiting the arrival of medical aid. Proper early measures may be instrumental in saving life and ensuring a better...

• fluoroscope instrument consisting of an X-ray machine (see X ray ) and a fluorescent screen that may be used by physicians to view the internal organs of the body. During medical diagnosis the patient stands between the X-ray machine, or other radiation source,...

• folk medicine methods of curing by means of healing objects, herbs, or animal parts; ceremony; conjuring, magic, or witchcraft; and other means apart from the formalized practice of medical science. In nearly...

• gene therapy the use of genes and the techniques of genetic engineering in the treatment of a genetic disorder or chronic disease. There are many techniques of gene therapy, all of them still in experimental stages. The two basic methods are called in vivo and ex vivo...

• geriatrics the branch of medicine concerned with conditions and diseases of the aged. Many disabilities in old age are caused by or related to the deterioration of the circulatory system (see arteriosclerosis ), e.g., mental deterioration and disturbances of motor and sensory function are often associated with an insufficient blood supply. Older persons are more prone to gastrointestinal disturbances,...

• gerontology see geriatrics.

• graft in surgery: see transplantation, medical.

• gynecology branch of medicine specializing in the disorders of the female reproductive system. Modern gynecology deals with menstrual disorders, menopause, infectious disease and maldevelopment of the...

• health insurance prepayment plan providing services or cash indemnities for medical care needed in times of illness or disability. It is effected by voluntary plans, either commercial or nonprofit, or by compulsory...

• health maintenance organization (HMO), type of prepaid medical service in which members pay a monthly or yearly fee for all health care, including hospitalization. The term "health maintenance organization" was coined by a health policy analyst, Dr. Paul Ellwood, in the early 1970s. Most HMOs involve physicians engaged in group practice. Because costs to patients are fixed in advance, preventive...

• health-care proxy legal document in which a person assigns to another person, usually called an agent or proxy, the authority to make medical decisions in case of incapacitation. It is, in essence, a power of...

• hearing aid device used in some forms of deafness to amplify sound before it reaches the auditory organs. Modern hearing aids are electronic. They contain a tiny receiver and a transistor amplifier, and are...

• heart, artificial external or surgically implanted mechanical device designed to replace a patient's diseased heart. The first one used on a human being, the Jarvik-7, was implanted (1982) in Barney Clark, who lived for 112 days; another patient, William Schroeder, lived 620 days. Two major drawbacks of the...

• heart-lung machine device that maintains the circulation of the blood and the oxygen content of the body when connected with the arteriovenous system; it is also called the pump oxygenator. The machine is used in...

• Heimlich maneuver emergency procedure used to treat choking victims whose airway is obstructed by food or another substance. It forces air from the lungs through the windpipe, pushing the obstruction out. If the...

• herbal early botanical book containing descriptions and illustrations of herbs and plants with their properties, chiefly those qualities that made them useful as medicines or condiments. Most of the...

• herbal medicine use of natural plant substances (botanicals) to treat and prevent illness. The practice has existed since prehistoric times and flourishes today as the primary form of medicine for perhaps as much...

• histocompatibility see transplantation, medical.

• holistic medicine system of health care based on a concept of the "whole" person as one whose body, mind, spirit, and emotions are in balance with the environment. Stressing personal responsibility for health, a holistic approach may include conventional medicine and...

• homeopathy system of medicine whose fundamental principle is the law of similars—that like is cured by like. It was first given practical application by Samuel Hahnemann of Leipzig, Germany, in the early...

• homograft see transplantation, medical.

• hospice program of humane and supportive care for the terminally ill and their families; the term also applies to a professional facility that provides care to dying patients who can no longer be cared for...

• hospital institution for the care of the sick, maintained by private endowment or public funds or both. General hospitals minister to all types of illness, while special hospitals are concerned with only...

• hydrotherapy use of water in the treatment of illness or injury. Although the medicinal and hygienic value of water was recognized by the early Greeks, hydrotherapy attained its widest use in the 18th and 19th...

• hygiene science of preserving and promoting the health of both the individual and the community. It has many aspects: personal hygiene (proper living habits, cleanliness of body and clothing, healthful...

• hysterectomy surgical removal of the uterus. A hysterectomy may involve removal of the uterus only or additional removal of the cervix (base of the uterus), fallopian tubes (salpingectomy), and ovaries (oophorectomy). It may be performed through a conventional abdominal incision or through the vagina. It is performed in cases of malignant tumors, endometriosis, prolapsed uterus, or fibroids that...

• immunization see immunity ; vaccination.

• immunology branch of medicine that studies the response of organisms to foreign substances, e.g., viruses , bacteria , and bacterial toxins (see immunity ). Immunologists study the tissues and organs of the...

• in vitro fertilization technique for conception of a human embryo outside the mother's body. Several ova , or eggs, are removed from the mother's body and placed in special laboratory culture dishes (Petri dishes); sperm from the father are then added, or in many cases a sperm is injected directly into...

• informed consent in medicine, a patient's written consent to a surgical or medical procedure or other course of treatment, given after the physician has told the patient all of the potential benefits, risks, and...

• injection introduction of a fluid into the body, usually by means of a needle and syringe. The material injected may be a test substance (as in determining allergic sensitivity or immunity to a disease), an...

• internal medicine branch of medicine concerned with nonsurgical remedies for diseases of the internal organs. While the internist is trained to diagnose and treat all pathologies of the various internal organs and systems, he may...

• intrauterine device (IUD), variously shaped birth control device, usually of plastic, which is inserted into the uterus by a physician. The IUD may contain copper or progesterone. Apparently the IUD creates a hostile...

• iron lung device used to maintain artificial respiration over an extended period of time. Before the successful vaccination program against poliomyelitis, it was used mostly in treatment of that disease. Currently, its main usage is in cases where the...

• kidney, artificial mechanical device capable of assuming the functions ordinarily performed by the kidneys. In treating cases of kidney failure a tube is inserted into an artery in the patient's arm and blood is...

• labor see birth.

• laparoscopic surgery see endoscope.

• life support system see artificial life support ; Life Support for Human Spaceflight under space science.

• liposome microscopic, fluid-filled pouch whose walls are made of layers of phospholipids identical to the phospholipids that make up cell membranes. Liposomes are used to deliver certain vaccines, enzymes, or drugs (e.g., insulin and some cancer drugs) to the body. When used in the...

• living will legal document in which a person expresses in advance his or her wishes concerning the use of artificial life support , to be referred to should the person be unable to communicate such wishes at the end of life. A living will usually goes into effect only when two physicians certify that a patient is unable to...

• lobotomy surgical procedure for cutting nerve pathways in the frontal lobes of the brain. The operation has been performed on mentally ill patients whose behavioral patterns were not improved by other forms of treatment. The procedure as pioneered by Nobel laureate Egas Moniz in the...

• lumbar puncture see spinal puncture.

• lysozyme see immunity.

• magnetic resonance imaging (MRI), noninvasive diagnostic technique that uses nuclear magnetic resonance to produce cross-sectional images of organs and other internal body structures. The patient lies inside a large, hollow cylinder containing a strong electromagnet, which causes the nuclei of...

• mammography diagnostic procedure that uses low-dose X rays to detect abnormalities in the breasts. The early diagnosis of breast cancer made possible by the routine use of mammography for screening women increases a woman's treatment alternatives and improves her chances of surviving the cancer. Mammograms can detect tumors too...

• managed health care system of health-care delivery that aims to control costs by assigning set fees for services, monitoring the need for procedures such as tests and surgical operations, and stressing preventive...

• massage treatment of superficial parts of the body by systematic rubbing, stroking, kneading, or slapping. Massages can be administered manually or with mechanical devices. They are sought most often to...

• mastectomy surgical removal of breast tissue, usually done as treatment for breast cancer. There are many types of mastectomy. In general, the farther the cancer has spread, the more tissue is taken. The radical mastectomies of the past (which removed not only the breast, but underlying...

• Mayo Clinic see Mayo, Charles Horace.

• Medicaid national health insurance program in the United States for low-income persons; established in 1965 with passage of the Social Security Amendments and now run by the Centers for Medicare and...

• Medicare national health insurance program in the United States for persons aged 65 and over and the disabled. It was established in 1965 with passage of the Social Security Amendments and is now run by the...

• medicine the science and art of treating and preventing disease.

• mercy killing see euthanasia.

• midwifery art of assisting at childbirth. The term midwife for centuries referred to a woman who was an overseer during the process of delivery. In ancient Greece and Rome, these women had some formal training. As the medical arts declined during medieval...

• neurology study of the morphology, physiology, and pathology of the human nervous system. As researchers, neurologists carry on investigative and experimental work in such areas as conductivity, embryology,...

• nonsusceptibility see immunity.

• nursing science of providing continuous care for sick or infirm people. While nursing as an occupation has always existed, it is only in fairly recent years that it has developed as a specialized...

• obstetrics branch of medicine concerned with the treatment of women during pregnancy, labor, childbirth (see birth ), and the time after childbirth. Obstetricians work to ensure that pregnancy culminates in the delivery of a healthy baby, without impairing the health of the mother. The mother's medical history...

• ophthalmology branch of medicine specializing in the anatomy, function and diseases of the eye. Ophthalmologists specialize in the medical and surgical treatment of eye disorders, vision measurements for glasses (refraction), eye muscle exercises (orthoptics), and the prevention of blindness...

• ophthalmoscope instrument used for examining the inner structure of the eye. The device was invented by the German physiologist H. L. F. von Helmholtz in 1851. His model consisted of three plates of glass pressed together and mounted on a handle at a 45° angle. A light was...

• optician filler of prescriptions for and dispenser of corrective lenses. An optician may grind lenses as instructed by the prescription of an optometrist (see optometry ) or ophthalmologist (see ophthalmology ) or transcribe the instructions for laboratory mechanics. The optician also fits and adjusts the lenses to the client and makes suggestions as to the selection of frames. Increasingly, opticians...

• optometry eye-care specialty concerned with eye examination, determination of visual abilities, diagnosis of eye diseases and conditions, and the prescription of lenses and other corrective measures. In...

• organ transplant see transplantation, medical.

• orthodontics see dentistry.

• orthopedics medical specialty concerned with deformities, injuries, and diseases of the bones, joints, ligaments, tendons, and muscles. Most of the early advances in orthopedics were made by practicing...

• osteopathy practice of therapy based on manipulation of bones and muscles. This school of medicine, founded by A. T. Still in 1874, maintains that the normal body produces forces necessary to fight disease and that most ailments are due to "structural derangement" of the body. Frequent slight strains are held to be capable of causing misalignment of bones and various other conditions of the muscle tissue and cartilage, and treatment is directed toward...

• oxygen tent device used to maintain a patient in an oxygen-rich environment. The oxygen tent is composed of a clear plastic sheet suspended over the bed and tucked beneath the mattress to provide an almost...

• pacemaker, artificial device used to stimulate a rhythmic heartbeat by means of electrical impulses. Implanted in the body when the heart's own electrical conduction system (natural pacemaker) does not function...

• Pap test   Pap smear, or Papanicolaou test , medical procedure used to detect cancer of the uterine cervix. A scraping, brushing, or smear, is taken from the surface of the vagina or cervix and is prepared on a slide and stained for...

• pathology study of the cause of disease and the modifications in cellular function and changes in cellular structure produced in any cell, organ, or part of the body by disease. The changes in tissue include degeneration, atrophy,...

• pediatrics branch of medicine dedicated to the attainment of the best physical, emotional, and social health for infants, children, and young people generally. Pediatrics became a specialty in 1930 when the...

• pedodontics see dentistry.

• periodontics see dentistry.

• PET scan or positron emission tomography , a medical imaging technique that monitors metabolic, or biochemical, activity in the brain and other organs by tracking the movement and concentration of a radioactive tracer injected into the...

• pharmacology study of the changes produced in living animals by chemical substances, especially the actions of drugs , substances used to treat disease. Systematic investigation of the effects of drugs based on animal experimentation and the use of isolated and purified active substances developed in the mid-19th...

• pharmacopoeia or pharmocopeia , authoritative publication designating the properties, action, use, dosage, and standards of strength and purity of drugs. It is compiled under the supervision of professional, usually...

• pharmacy art of compounding and dispensing drugs and medication. The term is also applied to an establishment used for such purposes. Until modern times medication was prepared and dispensed by the...

• physical examination see diagnosis.

• physical fitness combined good health and physical development. The object of any program of physical fitness is to maximize an individual's health, strength, endurance, and skill relative to age, sex, body build,...

• physical therapy or physiotherapy, treatment of disorders of the muscles, bones, or joints by means of physical agents—heat, light, water, manual and electronic massage, and exercise. Stroke, arthritis, fractures, and nerve damage...

• physician assistant (PA), health-care professional who provides patient services ranging from taking medical histories and doing physical examinations to performing minor surgical procedures; often called physician's...

• physician's assistant see physician assistant.

• physiotherapy see physical therapy.

• plasmapheresis see apheresis.

• plastic surgery surgical repair of congenital or acquired deformities and the restoration of contour to improve the appearance and function of tissue defects. Development of this specialized branch of surgery...

• podiatry science concerned with disorders, diseases, and deformities of the feet, also called chiropody. Podiatrists treat such common conditions as bunions, corns and calluses, and ingrown toenails. They...

• positron emission tomography see PET scan.

• post-mortem examination or autopsy, systematic examination of a cadaver for study or for determining the cause of death. Post-mortems use many methodical procedures to determine the etiology and pathogenesis of diseases, for...

• preimplantation genetic diagnosis see embryo biopsy.

• preventive medicine branch of medicine dealing with the prevention of disease and the maintenance of good health practices. Until recently preventive medicine was largely the domain of the U.S. Public Health Service or state and local...

• prophylaxis measures designed to prevent the occurrence of disease or its dissemination. Some examples of prophylaxis are immunization against serious diseases such as smallpox or diphtheria; quarantine to confine communicable disease; public health measures to ensure the safety of food, milk, and water; the care of teeth to offset decay; and restrictions put on persons with such disorders as...

• prosthesis see artificial limb.

• prosthodontics see dentistry.

• public health field of medicine and hygiene dealing with the prevention of disease and the promotion of health by government agencies. In the United States, public health authorities are engaged in many...

• quarantine isolation of persons, animals, places, and effects that carry or are suspected of harboring communicable disease. The term originally referred to the 40 days of offshore wait during which incoming...

• radioimmunoassay (RIA), highly sensitive laboratory technique used to measure minute amounts of substances including antigens, hormones, and drugs present in the body. The substance or antigen (a foreign substance...

• radiology branch of medicine specializing in the use of X rays, gamma rays, radioactive isotopes, and other forms of radiation in the diagnosis and treatment of disease. X ray machines and fluoroscopes are...

• rehabilitation see physical therapy.

• resuscitator device used to revive a person whose normal breathing has been disrupted. Several types are in wide use. The automatic tank resuscitator consists of a face mask that fits tightly over the nose and...

• Schick test diagnostic test designed to evaluate susceptibility to diphtheria. A small amount of diphtheria toxin is injected into the skin; the injection will produce an area of redness and swelling in individuals...

• socialized medicine publicly administered system of national health care. The term is used to describe programs that range from government operation of medical facilities to national health-insurance plans. In 1948,...

• sonography see ultrasound

• space medicine study of the medical and biological effects of space travel on living organisms. The principal aim is to discover how well and for how long humans can withstand the extreme conditions encountered...

• spinal puncture surgical penetration of the spinal canal by a hollow needle introduced between two of the lumbar vertebrae. The arrangement permits injection of antibiotics or anesthetics (see anesthesia ) as well as dyes to facilitate X-ray studies. It also allows withdrawal of cerebrospinal fluid (CSF), the plasmalike liquid cushioning the brain and spinal cord, in which case the procedure is...

• spinal tap see spinal puncture.

• splint rigid or semiflexible device for the immobilization of displaced or fractured parts of the body. Most commonly employed for fractures of bones, a splint may be a first-aid measure that allows the...

• sports medicine branch of medicine concerned with physical fitness and with the treatment and prevention of injuries and other disorders related to sports. Knee, leg, back, and shoulder injuries; stiffness and...

• stem cells unspecialized human or animal cells that can produce mature specialized body cells and at the same time replicate themselves. Embryonic stem cells are derived from a blastocyst (the blastula...

• stethoscope [Gr.,=chest viewer], instrument that enables the physican to hear the sounds made by the heart, the lungs, and various other organs. The earliest stethoscope, devised by the French physician R. T...

• stress test or exercise electrocardiography, in medicine, a test that evaluates the performance of the heart by subjecting it to controlled amounts of physical stress. Such tests, which include walking on a treadmill, measure the heart's...

• surgery branch of medicine concerned with the diagnosis and treatment of injuries and the excision and repair of pathological conditions by means of operative procedures (see also anesthesia ; medicine ;...