Become a Contributor

Medical Glossary - Definitions of Medical Terms

Medical Glossary - Definitions of Medical Terms

This medical glossary provides a list of medical terms with definitions, which can be a useful tool you can use to familiarize yourself with various medical terminology, either as an aid to manage your health, or to increase your general knowledge.
HealthHearty Staff
List of Medical Terminology - Glossary of Medical Terms with Definitions
A medical glossary containing a list of medical terminology and medical terms definitions can be useful in many ways. For instance, you can refer to it for common medical terms that your physician may have used at an appointment you had with him/her, which you may not have understood fully. Or, you could use it for the definitions of medical terms related to an illness you may be suffering from. This will not only help you in learning more about the ailment you have, but also serve to understand any medical terminology that may be unfamiliar to you, which you may come across while researching your options for treatment. Or you could simply browse through this medical terminology list just to gain knowledge on different medical terms and what the words stand for. For example, do you know what terms like Zoonosis, or Watermelon Stomach, or Kawasaki Disease are? Here is the alphabetical list of such terms:


Aarskog Syndrome: Also known as Aarskog-Scott syndrome, this is a genetic condition characterized by ocular hypertelorism, or eyes that are spaced abnormally wide, anteverted nostrils, or nostrils that are front facing, a malformation of the scrotum which is referred to as saddle-bag scrotum, a broadening of the upper lip, a backward bending of the knees due to a laxity in the ligaments, abnormally extensible fingers, and flat feet.

Abdominal Actinomycosis: This is a type of actinomycosis affecting the abdomen. Actinomycosis is a disease that cattle get and can be communicated to humans.

Abdominal Aortic Aneurism: A widening and ballooning of the aorta as it runs through the abdomen. At the point of the aneurysm, which can measure up to 3 cm in diameter, or even more, the wall of the aorta becomes weak and can even rupture, leading to catastrophic consequences.

Abdominal Bracing: A technique wherein the muscles of the stomach are tensed in order to provide spinal support.

Abdominal Cavity: The cavity in the abdomen which contains all the internal organs and entrails. The diaphragm separates this area from the thorax in mammals.

Abdominocentesis: Puncturing the abdomen with a hollow needle in order to draw fluid to carry out diagnosis.

Abdominoplasty: Also referred to as tummy tuck, abdominoplasty is a cosmetic surgical procedure which tightens the abdominal skin, smoothening out wrinkles.

Abdominal Hysterectomy: A surgical procedure wherein an incision is made in the abdomen to remove the uterus.

Abdominoscopy: A surgical procedure using a laparoscope. This is inserted into the abdomen, through a small incision, in order to carry out an examination of the area. The procedure is also known as laparoscopy or endoscopy. It helps to keep the surgical procedure minimally invasive.

Abductor Spasmodic Dysphonia: A condition wherein sudden spasms in the muscle results in causing the vocal cords to remain open. This causes a break in the voice, or the voice having a strained, tight, or strangled quality.

Ablation: Surgically removing a part of the body or tissue

Ablative Therapy: A kind of treatment wherein an organ's function is either removed or destroyed. For example, the ovaries being surgically removed, or administering some kinds of chemotherapy which results in stopping the ovaries from functioning.

Abortion: See definition of abortion.

Absorption: The process wherein nutrients are absorbed by the body from food after digestion.

Accessory Digestive Organs: Organs, such as salivary glands, tongue, liver, pancreas, and gallbladder, which aid the digestion process, although they do not belong to the digestive tract.

Accessory Movement: Movements of the joints which patients cannot perform in isolation or voluntarily.

Accommodation: The eye's ability to focus by automatically adjusting the focal length of its lens.

Acetylcholine: A neurotransmitter which is derived from choline. It helps in transmitting signals from the nerves.

Acquired Deafness: Hearing Loss which develops later in life.

Acquired Hemochromatosis: An accumulation of iron in tissues which occurs due to repeated blood transfusions, or when iron-rich foods are consumed excessively. It is characterized by the bronzing of skin, diabetes mellitus, enlargement of the liver, and abnormalcies in the joints and the pancreas.

Acquired Immune Deficiency Syndrome: A disease that occurs due to being infected by the human immunodeficiency virus, or HIV. It damages or kills the immune system's cells, which leads to the progressive impairment of the ability of the body in fighting infections or certain types of cancers. The disease is usually spread by coming into sexual contact with a partner having the infection or through contaminated hypodermic needles. When the HIV infection reaches advanced stages, it is referred to as AIDS.

Acquired Immunity: Immunity to certain diseases, which is not present at birth, but is acquired later in life. The immunity can occur due to the body developing antibodies because of being infected by a disease, by vaccination, or by antibodies being passed to an unborn child through the placenta.

Action Tremor: A tremor which increases if the hand is moved voluntarily.

Adenocarcinoma: The development of cancer in the inner surface or lining of any organ.

Adenoma: A non-malignant epithelial growth or tumor in the tissues of a gland.

Aerobic Activity: See definition of aerobic activity.

Alternative Medicine: See definition of Alternative Medicine.

Amsler Grid: This is a chart containing vertical and horizontal lines. These lines form a pattern of small boxes. Patients with macular degeneration that is age-related can use this chart to self-monitor their vision.


Balance Disorder: A disorder in the labyrinth, or the internal organ in the ear, which controls the system of balance and lets humans know how their bodies are positioned in relation to the environment.

Balloon Angioplasty: A procedure that is used for widening arteries which are narrowed. A catheter, which has a deflated balloon attached to its tip, is inserted in that part of the artery that is narrowed, and is then inflated. This results in dilating the artery.

Barium: A chalky, chemical, metallic liquid which is used for coating the inner parts of organs so that they become visible on X-ray pictures.

Basal Body Temperature: The temperature of an individual taken early in the morning, after a night's sleep, prior to any activity such as getting off the bed, talking, eating, etc.

Basal Metabolic Rate (BMR): BMR is the measurement of the energy that is required for the body to function at rest. The measurement is made in calories. There is an increase in the metabolic rate when there is exertion, fear, stress, or illness.

Behavioral Science: See definition of behavioral science.

Beta Blocker: A drug that is used in the treatment of arrhythmia or hypertension (high blood pressure). It decreases the contraction rate of the heart by blocking the beta-andregenic receptors of the autonomic nervous system.

Beta Cells: Clusters of insulin making cells located in the pancreas known as the islets of Langerhans.

Biarthrodial Muscles: Muscles spanning across two joints which help in the functioning of those joints.

Bilateral: Affecting two sides of the body. For instance, cancer that occurs in both breasts is known as bilateral breast cancer. It is referred to as synchronous if it occurs at the same time, and metachronous if it occurs at different times.

Biliary Tract: Also known as the biliary tree or biliary system, it includes the bile ducts and the gallbladder.

Binocular Vision: Vision involving the ability of using both eyes synchronously, which results in producing a single image.

Biologic Response Modifiers: Substances which boost the immune system of the body in order to combat cancer.

Bismuth Subsalicylate: A non-prescription medication for treating diarrhea, indigestion, nausea, and heartburn. It is also used for treatment of ulcers that are caused by a bacterium known as the Helicobacter pylori.

Blink Rate: The rate at which the eyelids blink automatically per minute (usually it is 10-30 times a minute).

Blood Plasma: The colorless watery part of the blood which contains blood cells, nutrients, proteins, glucose, enzymes, minerals, and other matter.

Blood Pressure Cuff: Also known as the sphygmomanometer, this device is usually put around the upper arm for measuring blood pressure.

Blood-Brain Barrier: The membrane which separates the brain cells and the circulating blood.

Body Fat Percentage: It is the mass of fat divided by the total body mass.

Body Mass Index (BMI): A number which is derived by using measurements of height and weight, which is indicative of whether the weight is within a range that is considered healthy.

Bone Density Test: A test used for measuring the density and strength of bones. It is usually used for determining whether there is a risk of osteoporosis developing.


CA-125 Test: A blood test for detecting elevated levels of CA-125, which is a protein antigen, which can be indicative of the development of ovarian cancer, and other disorders.

Calcium Channel Blocker: A medicinal drug used for treating heart disease.

Calculi: Solid lumps or stones which for in the body, e.g., gallstones.

Cancellous Tissue: The spongy tissue within bones.

Cancer: Cells which divide abnormally, invading tissues nearby, or spread via the lymphatic system and blood stream to other areas in the body.

Candidiasis: An infection that is caused by fungi of the genus Candida. It exists normally in the gastrointestinal tract. An infection usually occurs when the fungus suddenly overgrows because of surgery or some other changes in the body.

Capsule: The cell layer that surrounds an organ, e.g. the prostate gland's capsule.

Carcinogen: A cancer-causing substance.

Cardiac: Anything that pertains to the heart, e.g. cardiac arrest, which means the cessation of heartbeat.

Cardiology: The branch of medical study and practice dealing with the heart and its maladies.

Caroli's Disease: This is a congenital condition wherein there is an enlargement of the liver's bile ducts, which can cause infection, irritation, or gallstones.

Cathartics: Purgative medicines, also called laxatives, which stimulate the emptying of the bowels.

Catheter: A flexible tube utilized for draining fluids from the body, or injecting them into the body. For example, the Foley catheter is used for draining urine out of the bladder.

Cecostomy: A catheter that is inserted through the abdomen into the cecum, or the beginning of the large intestine in order to remove feces or gas. This is particularly useful as a short-term method of protecting a portion of the colon while healing after surgery. It is also used by patients experiencing fecal incontinence by administering a small amount of phosphate enema, and then a saline enema, in order to evacuate feces from the large intestine completely.

Cellular Pathology: Also known as cytopathology, it is the study of the alteration of cells in disease.

Central Auditory Processing Disorder: The inability of people with normal intelligence and hearing to recognize, understand, or differentiate sounds.

Cerebral Embolism: A blood clot that is carried by the blood stream from some other area of the body to the brain where it causes blockage of an artery.

Cerebral Hemorrhage: Bleeding inside the brain.

Cerebral Thrombosis: A blood clot forming in an artery which carries blood to the brain.

Chelation Therapy: See what is Chelation Therapy.

Chemosensory Disorders: Diseases or disorders of taste and/or smell.

Chlorhydria: Excessive hydrochloric acid inside the stomach.

Cholecystitis: The inflammation of the wall of the gallbladder.

Cholethiasis: The gallbladder having gallstones inside it.

Chorea: The body moving in a rapid, dance-like, jerky manner because of a degenerative nervous disorder.

Chronic Depression (Dysthymia): See what is Chronic Depression (Dysthymia).

Complementary Therapy : See definition of complementary therapy (alternative medicine).

Corticosteroids: Hormones that are anti-inflammatory which are produced in the body naturally or are made synthetically to be used as drugs. Prednisone is one of the most common drugs of this kind which is prescribed to treat arthritis, and also as an immunosuppressant.


Debridement: Surgically removing damaged, infected, or infected tissue and/or foreign matter from a burn or wound.

Decibel: The unit for measuring the loudness or intensity of sound.

Deciduous Teeth: Also referred to as primary or baby teeth.

Defibrillator: An electronic machine used for administering an electric shock, of a voltage that is preset, on the chest, for restoring the normal rhythmic beating of the heart.

Deja Vu: See what is Deja Vu.

Delusions: A condition wherein the patient loses his/her ability to discern reality, experiencing misperceptions, and hallucinations.

Dental Amalgams: Also known as silver fillings, this is a mixture of 45-50 percent of mercury and 50-55 percent of an alloy made of tin, copper, and silver, which is used for repairing teeth that are decayed.

Dental Fluorosis: A condition caused by drinking water that has too much fluoride in it. It results in teeth becoming discolored, with the enamel getting stained, pitted, or spotted.

Depth Perception: The ability of distinguishing physical objects in a field of vision.

Dermatopathology: Making a diagnosis of skin diseases by studying the skin.

Diastolic Blood Pressure: The lowest measure of blood pressure in the arteries, occurring between heartbeats.

Digestants: Medicines which stimulate or aid digestion.

Dilation And Curettage (D & C): A gynecological surgical procedure wherein the cervical canal is widened with the help of a dilator and a curette is used to scrape the uterine cavity.

Diplopia: An impairment of the vision which results in a single object appearing as double objects.

Disc Herniation (Herniated Disc or Bulging Disc): Also referred to as slipped disc, disc bulge, or disc prolapse, it is a condition wherein the tissue separating the vertebral bones of the spine gets ruptured. When this happens, it usually creates pressure on the spinal nerves, thus causing pain, numbness or weakness in the arm and neck.

Distention: Swelling or bloating of any part of the body like the abdomen.

Diuretic: A medication that increases the formation of urine so that the body can get rid of excessive fluids. The term 'diuretic' is derived from the Greek 'dia', which means 'thoroughly', and 'ourein', which means 'to urinate'. Diuretics are also used to reduce blood pressure because of this reason.

Diverticulosis: A condition wherein small bulging pouches, or diverticula, form in the weak areas of the colon, which can become infected and inflamed, and can even lead to certain kinds of cancer.

Dopamine: A chemical, which is a neurotransmitter, in the brain which regulates balance, movement, and walking.

Down Syndrome: Down syndrome is a chromosomal disorder that is caused by the presence of all or part of an extra 21st chromosome. Down syndrome is associated with impairment of cognitive ability, physical growth, and facial appearance.

Dual Energy X-Ray Absorptiometry (DEXA): A technique of imaging using low doses of radiation to check the density of bone in order to diagnose osteoporosis.

Durable Power of Attorney: A legal document which designates a member of the family or a friend whom you appoint as your guardian in the event of you being unable to make medically-related decisions for yourself.


Earwax: A yellow, waxy substance secreted by the glands located in the ear canal, also called cerumen, which protects from getting infected by keeping the skin dry.

Eczema: A condition wherein the skin gets inflamed causing itching and, often, even scaling, crusting, or blisters sometimes.

Edema: Swelling caused by the accumulation of excessive fluid in tissues, cells, or serous cavities.

Ejection Fraction: Measurement of the amount of blood that is pumped out from the ventricles.

Elective Surgery: An operation that is not required but which an individual opts for. It is also referred to as Optional Surgery.

Electrocardiogram (EKG OR ECG): A test used for recording the heart's electrical activity. It is helpful for detecting damage of the heart muscle, and also shows abnormalities in the rhythms, also known as dysrhythmia or arrhythmia.

Electrocoagulation: Using high-frequency electric current, which is applied by a needle or metal instrument, to coagulate (clot) blood in order to stop bleeding.

Electroconvulsive Therapy (ECT): Administering a controlled amount of electric current to the brain inducing mild convulsions. This technique is used for treating psychiatric illnesses such as severe depression.

Electrodermal Activity (EDA): Measuring changes in the rate of perspiration.

Electromyogram (EMG): A test used for evaluating muscle and nerve function.

Electrosurgery: Destroying cancer cells or any other tissue, such as warts, by using high-frequency current.

Embolus: A particle, such as a blood clot or an air bubble, in the blood stream.

Encephalitis: The brain infected with a virus which results in inflammation. Some of the symptoms of this condition are headache, pain in the neck, nausea, drowsiness, and fever.

Endarterectomy: Surgically removing blood clots or plaque in arteries.

Endocardium: The membrane covering the surface inside the heart.

Endocervical Curettage (ECC): A procedure wherein a narrow instrument, known as a curette, is used for scraping the endocervical canal's lining. This kind of biopsy usually is done along with colposcopic biopsy.

Endodontist: Also referred to as a Pulp Specialist, an Endodontist specializes in root canal treatment.

Endometrium: The mucous membrane that lines the uterus' inner surface, which thickens during each cycle of menstruation, and is shed in the menstrual blood.

Endorphins: Neurochemicals that occur naturally in the brain, which have pain killing properties, and are usually produced when the body experiences physical stress.

Endoscopy Retrograde Cholangiopancreatography (ERCP): A procedure involving the insertion of a viewing tube, or endoscope, into the small intestine via the stomach. A special kind of dye is injected, which shows the biliary system's ducts.

Extrinsic Asthma: Asthma that gets triggered due to an allergic reaction, generally because of something inhaled.


Fallopian Tubes: Two tubes extending from either side of the uterus, going towards the ovaries, which act as a passageway for eggs.

False Negative Report: A report that shows negative results, although it is actually positive.

False Positive Report: A report that shows positive results, although it is actually negative.

Fatty Liver: Also known as Steatosis, this is a condition wherein certain fats, like triglycerides, accumulate in the liver, which usually occurs because of alcoholic cirrhosis, or due to certain toxins, or pregnancy.

Fecal Incontinence: The inability to hold stools in the rectum or colon, which results in involuntary bowel movements occurring.

Fecal Occult Blood Test: A test to check for cancer of the rectum or colon by examining if there is hidden blood in the stools.

Festination: Quickening the gait and shortening the stride involuntarily in order to maintain balance. This condition occurs due to certain diseases, such as Parkinson's disease.

Fibrillation: The fibers of the heart muscle contracting rapidly, in an uncoordinated manner. Unless it is stopped, this condition can be fatal.

Fibroadenoma: Firm and movable lumps in the breast, which are noncancerous. They occur commonly in young women because of high estrogen levels.

Fibroids: Benign growths that contain fibrous tissue, which usually occur in the uterus.

Fibrosis: The formation of scar tissue which can be caused due to injury, inflammation, infection, and even healing.

Fibrositis: A protracted process of disease which occurs intermittently and has no underlying pathological cause.

Fine Needle Aspiration: Using a hollow, narrow needle to extract tissue.

Flexor Muscle: Any muscle used for bending a limb or any other part of the body.

Follicle Stimulating Hormone (FSH): A hormone that the pituitary gland secretes which helps in stimulating the formation and development of eggs in women and sperm in men. It also induces the production of sex hormone in both women and men.

Food Intolerance: An adverse reaction to certain foods wherein the immune system is not involved, such as lactose intolerance.

Free Skin Graft: Taking healthy skin from one area of the body to be grafted on other areas where the skin is damaged or lost.

Frozen Shoulder: Also known as 'capsulitis', this is a condition wherein the connective tissue of the shoulder gets stiff, thus severely restricting movement of the joint. While this is sometimes caused due to injury, often it occurs spontaneously, without any obvious trigger factors.


Gamete Intrafallopian Transfer (GIFT): An infertility treatment wherein the eggs are removed from the ovaries of a woman and combined with her partner's or a donor's sperm, and then placing both the sperm and eggs in her fallopian tube for fertilization to take place.

Ganglion: A collection of nerve cells which are encapsulated in a neural structure.

Ganglion Cysts: Non-cancerous cysts which are filled with fluid occur commonly as lumps, usually on the back portion of the wrist.

Gardner's Syndrome: A condition wherein there is formation of a large number of polyps in the digestive tract.

Gastric Juices: Fluids that are secreted in the stomach, which consist mainly of mucin and hydrochloric acid, along with the enzymes rennin, pepsin, and lipase, which help in breaking down food and killing bacteria.

Gastrocolic Reflex: An increase in the movement of muscles in the gastrointestinal tract on food entering the stomach when it is empty. This often results in the urge for bowel movement soon after consuming food.

Gastroenteritis: Infection and inflammation of the digestive tract, that could be caused by parasites or bacteria from unclean water or spoiled food, or consuming food which causes irritation to the lining of the stomach, or emotional reasons like stress, fear, or anger.

Gastrointestinal (GI) Tract: Also termed as digestive tract or alimentary tract, this is a tube extending from the mouth right up to the anus.

Gastronomy:An opening made artificially into the stomach through the wall of the abdomen for a feeding tube to be inserted.

Gated Blood Pool Scan: A nuclear scan made to check for the amount of blood expelled with each beat of the heart and the movement of the heart wall soon after a patient finishes walking on a treadmill or riding a stationary bike.

General Anesthetic: An anesthetic used for anesthetizing the whole body and causing unconsciousness during surgery.

Genes: These are basic hereditary units, each having a specified place in the chromosomes of an individual. The genes determine the color of the eyes, the type of hair, the height, etc. of each person, which they inherit from their progenitors.

Genital Herpes: A disease that is transmitted sexually, which is caused by a virus called the herpes simplex.

Genu Valgum: A condition wherein the thighs slant inwards causing knock knees.

Genu Varum: A condition in which the legs are bowed outwards, either at the knees or below them, which is also termed as 'bowed legs'.

Glucose: This is the body's primary source of energy. It is a sugar that is derived from metabolizing carbohydrates, and is easily converted into energy.

Gluten Intolerance: A condition wherein wheat protein, or gluten, cannot be tolerated. People with this condition must avoid grains that contain gluten such as wheat, barley, oats, and rye.

Gluteus Maximus: It is the outermost among the three gluteal, or buttock, muscles.

Glycogen: One of the forms in which the body stores fuel. It is stored mainly in the liver and is converted into glucose when the body requires it.

Gonadotropins: This is a hormone that the pituitary gland secretes which stimulates the gonads where gametes, or sex cells, are produced.


H2-Blockers: Medications that block histamine2 in order to inhibit the production of acid in the stomach.

Hair Cells: These are sensory cells located in the inner ear. They are topped by stereocilia, or hair-like anatomical structures, which convert the mechanical energy that sound waves produce into nerve impulses.

Halitosis (Oral Malodor): Also known as foetor oris, or stench in the mouth, or simply bad breath. These days it is referred to as Oral Malodor.

Hallucinosis: A psychological condition wherein an individual hallucinates continuously.

Hallux Rigidus: A condition wherein the metatarsophalangeal joint, or the joint of the big toe, loses its range of movement.

Hamstrings: Muscles that are found in the posterior part of the thighs.

Hay Fever: Also referred to as rhinitis, this is a seasonal condition that afflicts people who are allergic to pollen.

Headache, Primary: These types of headaches are not related to any underlying pathological causes. They include tension induced headache, migraine, and cluster headache.

Headache, Secondary: This type of headache is caused by an underlying pathological reason. Also referred to as inflammatory or traction headaches, they include any headache that has neoplastic, infectious, drug-induced, idiopathic, or vascular origins.

Heart Block: When the electrical impulses to the heart muscles are interrupted. This results in unconsciousness.

Heart Valve Prolapse: A condition wherein the heart valve remains open partially when it ought to be closed.

Heart-Lung Machine: A machine that maintains the circulation of blood, by diverting it, oxygenating it, and then pumping it back into the body, during surgery of the heart.

Heberden's Nodes: Bony swellings which form around the joints, due to the degenerative effects of arthritis.

Hematopathology: Also referred to as Hemopathology, this is branch of study that deals with blood, the organs that produce blood, bone marrow, and the diseases that affect them.

Hemorrhage: The medical word for excessive bleeding.

Hemorrhoidectomy: Removing hemorrhoids surgically. Hemorrhoids are swellings inside or at the anal sphincter.

Hepatitis: The liver getting inflamed either due to a toxin or being infected by a virus.

Hepatologist: A physician specializing in diseases of the liver.

Herbal Medicine: See definition of herbal medicine.

High Density Lipoprotein (HDL): Also referred to as the 'good cholesterol', it helps in breaking down and removing 'bad' cholesterol from the body.

Histamine: A chemical that is released by the body due to an allergic reaction.

Holistic Health: See definition of holistic health.

Homeopathy: See definition of homeopathy.

Hormone Replacement Therapy (HRT): Replacing female hormones such as progestin, which is the synthetic version of progesterone, and estrogen, when women no longer produce them after menopause.

Human Brain: See facts about Human Brain.

Human Chromosomes: See facts about Human Chromosomes.

Hyaluronic Acid (HA): Hyaluronic acid, also known as Hyaluronan is found in the human body, mainly in the fluids in eyes and joints.


Ileal: Related to the lowest part of the small intestines, or the ileum.

Ileitis: Also known as Crohn's Disease, it is a condition wherein the ileum gets inflamed.

Imaging: A diagnostic procedure wherein pictures of the inner parts of the body are taken for making evaluations.

Immobilization: The prevention of movement in order to allow healing to take place.

Immune System: A network of special organs and cells which function together, defending the body from being attacked by viruses and bacteria.

Immunoglobulins: Proteins and antibodies that are produced by the immune system's cells, found in the tissue fluids and blood, which bind to anything they recognize as foreign antigens. Sometimes immunoglobulins bind to substances that may not be a health threat.

Immunology: The study of the immune system of the body - how it functions and what are the disorders that affect it.

Immunosuppressive Medications: Medications which suppress the immune system of the body, usually used to minimize transplanted organs from being rejected.

Immunotherapy: A therapy that is designed to make the body resistant to substances that it is allergic to like dust mites, pollens, insect venom, and fungi by giving the person increasing doses of the allergen he/she is allergic to. It is also a treatment wherein the natural defenses of the body to fight disease is used.

Impaction: An object trapped in a passage of the body, like hardened stool trapped in the colon or stones caught in the bile duct.

Impaired Glucose Tolerance (IGT): A condition wherein blood sugar levels are elevated higher than normal, although not to the extent of being diagnosed as diabetes. It is an indication of prediabetes or borderline diabetes.

Impedance Plethysmography: A test which evaluates the flow of blood through the leg.

In-Vitro Fertilization (IVF): An infertility treatment wherein the egg from a woman is taken and fertilized in the laboratory with either the sperm from her partner or a donor.

Inflammatory Bowel Disease (IBD): Chronic problems causing the gastrointestinal tract to get inflamed, also resulting in ulcers. Some of the common conditions are Crohn's Disease and colitis.

Informed Consent Form: A form which a patient signs before undergoing surgery, which states everything that the surgery involves, including the risks.

Inotropic Medications: Medications which increase the strength of the heart's contractions.

Inspiration: Inhalation; Breathing in of oxygen.

Insulin: A hormone that the isles of Langerhans, located in the pancreas, secretes. Insulin regulates the amount of glycogen stored in the liver and helps in accelerating the oxidation of sugar.

Insulin Dependent Diabetes (Type 1 Diabetes): Also known as Type 1 Diabetes, this is a condition wherein the immune system of the body destroys the insulin producing cells in the pancreas. Insulin is required by the body for cells to get glucose for energy. People afflicted with this kind of diabetes mellitus (DM) have to take insulin injections daily.

Insulin Resistance (IR): A condition wherein the cells' ability to respond to insulin is impaired, resulting in the body secreting increased amounts of insulin in the blood in order to reduce the levels of blood glucose.


Jackknife Seizure: Also referred to as Infantile Spasms, it is a disorder that occurs in infancy with the onset of myoclonic seizures, mental retardation, and abnormal electroencephalogram.

Jacob's Disease: Also referred to as Creutzfeldt-Jakob Disease (CJD), it affects the brain causing dementia, which is thought to be caused by a prion. Apart from chronic dementia, the other symptoms include nervousness, forgetfulness, trembling jerky movements of the hands, muscular spasms, unsteady gait, balance disorder, and loss of expression in the face.

Jejunum: The portion of the small intestines that is between the duodenum and the ileum.

Jenner's Method: Inoculating a weakened form of a virus in order to produce immunity to the disease it causes. It is also known as Jennerization.

Joint Locking: A condition which is very painful, generally caused by a loose body being entrapped within a joint, between the surfaces of the joint.

Jordan Frame: A special stretcher meant for transporting patients with spinal injury.

Jugular Veins: Veins carrying blood back to the heart from the head.

Jumper's Knee: The degeneration of the tendon attached to the lower part of the knee-cap, or the patella, resulting in tenderness of the area and pain.

Junctional Epidermolysis Bullosa: A condition that causes blistering of the skin because of a mutation of a gene which in normal conditions helps in the formation of thread-like fibers that are anchoring filaments, which fix the epidermis to the basement membrane. The lack of these anchoring elements results in the separation of tissue, which causes the blistering that is evident on the topmost layer of the basement membrane.


Kanner Syndrome: Also referred to as Autism, this is one of the neuropsychiatric conditions typified by deficiencies in communication and social interaction, and abnormally repetitive behavior.

Kaposi's Sarcoma: A kind of malignancy of the skin that usually afflicts the elderly, or those who have problems in their immune system, like AIDS. It is characterized by purplish, soft papules or plaques which form nodules. The condition usually begins in the lower part of the leg and then spreads to other areas of the body, like the arms and hands, gradually.

Kartagener Syndrome: A hereditary condition characterized by inflammation and widening of the bronchi, or bronchiectasis, sinusitis, heart being located on the right side, or dextrocardia, and inferitily.

Kawasaki Disease: A condition that is not related at all to the popular brand of motorbike with the same name, but is a disease whose origins are unknown. Children are the ones who are mainly affected by it. It causes fever, conjunctivitis, reddening of the mucous membranes in the mouth, swelling in the neck glands, gingivitis, and a raised, bright red rash that forms on the skin of the feet and hands, becoming like socks and gloves, which hardens and peels off.

Kearns-Sayre Syndrome: A neuromuscular condition characterized by three main features: Pigmented material accumulating abnormally on the retina, referred to as atypical retinitis pigmentosa; Certain muscles of the eyes becoming paralyzed progressively, referred to as CPEO, or chronic progressive external ophthalmoplegia; and cardiomyopathy, or heart disease.

Keratitis: The cornea getting inflamed resulting in blurred vision and painful, watery eyes.

Keshan Disease: The deficiency of selenium, which is an essential mineral, causes this condition. It is a disease that affects the heart muscle, and is potentially fatal. It was discovered first in Keshan, a province in China, hence its name. However it has been found in other places as well, and occurs in areas where the soil is deficient in selenium.

Ketoacidosis: Acidosis wherein ketone bodies get accumulated, which usually happens in patients afflicted by diabetes.

Ketone: A product that results from the breaking down of fat, which accumulates in the blood due to either inadequate levels of insulin or deficient intake of calories.

Knee Reconstruction: Surgically restoring the knee's biomechanics.


Labyrinth: The organ that helps the body to balance. Consisting of three semicircular shaped canals along with the vestibule, it is located in the inner part of the ear.

Labyrinthine Hydrops: Excessive accumulation of fluid in the labyrinth, or the organ of balance, which results in fullness or pressure in the ears, dizziness, loss of hearing and balance.

Lactase: An enzyme secreted in the small intestines which is required for digesting lactose, or milk sugar.

Laminectomy: Surgically removing a part of the lamina in order to make more space in the vertebral canal. It is usually done for treating spinal canal stenosis or disc herniation.

Landau-Kleffner Syndrome: A disorder that occurs in childhood wherein there is a sudden or gradual loss in the ability of understanding and using spoken language.

Laparoscope: A thin tube attached with a tiny video camera, which is used to examine the inside parts of the body and check the surfaces of organs.

Laparoscopic Colectomy: An operation wherein the gallbladder is removed with the help of a laparoscope. The laparoscope along with other surgical instruments are inserted through small incisions made in the abdomen. The camera attached to the laparoscope displays the gallbladder on a TV screen, which helps the doctor to remove it.

Laryngeal Neoplasms: Noncancerous or cancerous growths in the larynx, or voice box.

Laryngeal Paralysis: The loss of feeling or function in either one or both the vocal folds.

Laryngectomy: Surgically removing part or whole of the voice box or larynx.

Larynx: The structure of valves that lie between the windpipe, or trachea, and the upper throat, or pharynx. It consists of vocal cords which produce the vocalization in speech.

Lavage: The process wherein an organ, e.g. the stomach or bowel, is washed or cleansed, by flushing it out with water.

Laxatives: Also referred to as cathartics, these are medicines that are used for relieving constipation.

Lens: Also known as crystalline lens, this is the transparent, biconvex structure located behind the iris. Its function is to focus the rays of light on the retina to produce an image of the object seen.

Lesion: A wound or injury.

Levodopa (L-DOPA): A drug used for treating Parkinson's Disease (PD). It changes into dopamine in the brain.

Lewy Body: A pink sphere that stains dying cells, which is considered to be a sign of Parkinson's Disease.

Ligament: A band or sheet of tough and fibrous tissue which connects bones, binding joints together.

Lipid: A fatty matter found in blood.

Lipoproteins: The primary means by which lipids or fatty substances are transported in the blood.

Lithotripsy, Extracorporeal Shock Wave (ESWL): A method by which gallstones and bile stones are broken up using shock waves with a specialized tool.


Magnetic Field Therapy: A method wherein an alternating magnetic filed is used for generating an electric current within tissues, which results in changes in the flow of blood.

Magnetic Resonance Imaging (MRI): A non-invasive technique which creates a two-dimensional image of an internal structure or organ, such as the spinal cord or the brain.

Malabsorption Syndromes: Conditions wherein the small intestine loses the ability to absorb nutriments from foods.

Malignant Tumor: A mass of cells that are cancerous which can affect the tissues surrounding it, or spread to other parts of the body.

Mallet Finger: A condition caused by the rupturing of the finger's long extension tendon.

Malocclusion: A dental problem which is also known as 'bad bite'. It is caused due to missing, crooked, or crowded teeth, a misalignment of the jaw, or extra teeth.

Mammogram: An X-ray picture of the breast, usually used to check for breast cancer.

Manic Depression: See what is manic depression.

Manometry: Tests which measure the movements and pressure of the muscles of the gastrointestinal tract.

Mast Cells: Cells that synthesize as well as store histamines. These are found in most tissues of the body, especially just under the epithelial layer, around blood vessels, and serous cavities.

Mastitis: The inflammation of the milk ducts of the breast due to infection.

Mastoid: The temporal bone located behind the ear, at the skull's base.

McMurray Test: This is a test for checking if there is a lesion in the medial meniscus of the knee.

Meal Plan: A guide which helps people design their diet to include proper amounts of proteins, carbohydrates, minerals, vitamins, fiber, and calories.

Mean Blood Pressure: The average of the blood pressure, after taking into account the fall and rise which occurs with each beat of the heart. The estimation is usually made by taking the diastolic pressure and multiplying it by two, adding this with the systolic pressure, and dividing the resulting number by three.

Median Nerve: The nerve that runs down the arm, through the wrist's carpal tunnel. It services the first three fingers and the thumb of the hand. Carpal Tunnel Syndrome (CTS) occurs when the median nerve gets inflamed.

Megacolon: Severe constipation resulting in the colon getting huge and swollen.

Meige Syndrome: This is a malfunction of movement which is characterized by forceful and involuntary muscular contractions of the tongue and jaw, referred to as oromandibular dystonia, along with muscular spasms around the eyes, called blepharospasm.

Melanocytes: Cells that are found in the epidermis' basal layer that produce melanin, which is the pigment of the skin.

Melena (Blood in Stool): Stool containing blood, usually due to bleeding in the gastrointestinal tract.

Menetrier's Disease: Also referred to as Giant Hypertrophic Gastritis, it is a chronic disease causing large folds of tissue forming in the stomach's wall. There could be inflammation of the tissue and it may also contain ulcers. People afflicted with this disease have a high chance of getting stomach cancer.

Mesothelioma: See what is mesothelioma.

Moles: See meaning of moles on the face.

Mountain Sickness: See what is Altitude Sickness.

Mumps (Infectious Parotitis): See what is Parotitis (Mumps).


Near Point of Accommodation: The point that is the closest at which an object can be perceived distinctly by the eye.

Near Point of Convergence: The maximum degree to which both the eyes can turn inward.

Needle Aspiration (Of the Breast): This is a type of biopsy using a thin, hollow needle to remove a tumor's cells or fluid from a cyst by suction The samples aspirated, or drawn up, are then examined under a microscope.

Neoadjuvant Therapy: Treatment like hormonal therapy or chemotherapy which a patient is given prior to undergoing surgery. This therapy is useful by helping to shrink tumors, such as those that occur in the breast, so that the surgical procedure for removing them becomes less complicated.

Nephrectomy: Surgically removing the kidney.

Nephropathy: Damage caused to the kidney due to long years of diabetes which involves high levels of glucose in the blood.

Nerve Conduction Test: A procedure that helps to determine the generation of nerve impulses.

Neural Mobilization: This is a technique by which the nerves are stretched gently to relieve the tension that may have accumulated in them which cause symptoms like radiating pain, tingling sensations, weakness, or numbness.

Neural Plasticity: The ability of the nervous system and the brain to adapt to changes brought about by new conditions, like after an injury.

Neural Tube Defect: A kind of birth defect, like spina bifida, resulting from the failure of the brain or the spinal cord developing normally in the fetus.

Neuralgia: A disorder of the nervous system which results in acute pain along the affected nerve's pathway.

Neuritis: The inflammation of nerve cells, or neurons, which is usually characterized by numbness, pain, or tingling in the affected area.

Neurofibromatosis: Also referred to as Von Recklinghausen's Disease, this is an inherited disorder wherein numerous spots and neurofibromas form on the skin, which are non-cancerous, often accompanied by abnormalities in development.

Neurogenic Communication Disorder: The inability to communicate with others due to hearing, language, and speech problems, which are caused by the nervous system becoming impaired.

Neuron: Also called a nerve cell, this is a unique kind of cell that is present both in the brain and the body, which is specialized for processing and transmitting information, either from one area of the brain to another, or from the brain to a part of the body and vice versa.

Neurotransmitters: Chemicals that occur naturally in the brain that transmit impulses, or messages, between nerve cells. They exist in the space, or synapse, that separates the terminal of the neuron transmitting the message, which is called the axon, from the terminal of the neuron receiving the message, called dendrite.

Nissen Fundoplication: An operation for sewing up the fundus, or the top area of the stomach, around the esophagus. It is carried out to stop the contents of the stomach from returning into the esophagus, a condition known as reflux, and for repairing a hiatal hernia (hiatus hernia).

Noise Induced Hearing Loss: Loss of hearing caused by either a single or repeated exposure to extremely loud sounds.

Non Insulin Dependent Diabetes Mellitus (Type 2 Diabetes): Also called Type 2 Diabetes, this is a condition wherein either the body loses the ability of adequately using the insulin it produces to convert blood glucose into energy, or it produces too little insulin. This condition can be controlled by diet, weight loss, and exercise, or it could require using insulin injections or oral medications.

Non-Invasive Procedure: A diagnostic treatment or technique which does not involve making incisions in the body.

Non-Steroidal Anti-Inflammatory Drugs (NSAIDS): A category of drugs, such as ibuprofen, aspirin, nabumeton, and naproxen, used for relieving pain and inhibiting inflammation in diseases like arthritis, which are not steroids like prednisone.


Obesity: See definition of obesity.

Obstruction: A blockage formed in the gastrointestinal tract which results in the obstruction of the passage of solids and liquids through it.

Occluded Artery: An artery in which the formation of plaque narrows it, thus impeding the flow of blood through it.

Occult: Symptoms or diseases which cannot be readily detected, either by laboratory tests or physical examination.

Ocular Hypertension: A condition wherein the eye's intraocular pressure is higher than normal, without any apparent defects in the visual field or damage to the optic nerve. In time, there are chances of this condition developing into glaucoma.

Olfaction: The faculty which helps us to discern scents.

Olfactometer: A device used for testing how intense a person's sense of smell is.

Oncogenes: Genes which promote the normal division of cells.

Oncologist: A physician specializing in the treatment of cancer, such as radiation oncologist, surgical oncologist, gynecologic oncologist, medical oncologist, and pediatric oncologist.

Oophorectomy: Surgically removing either one or both the ovaries.

Open Surgery: Cutting open the body and exposing the organs and structures involved during the surgical procedure.

Open-Set Speech Recognition: Not requiring visual clues to understand speech, also referred to as speech reading.

Oral And Maxillofacial Surgeon: A facial orthopedic surgeon who specializes in the treatment of a wide range of dental conditions, such as reconstructive surgery of the face and removing impacted teeth.

Oral Dissolution Therapy: Medicines taken orally to dissolve gallstones.

Oropharynx: The posterior region of the mouth which includes the base of the tongue, the tonsils and the soft palate.

Orthodontics: The field of dentistry which deals with the correction and prevention of abnormalities of the teeth, jaw, and bite.

Orthokeratology: Correcting refractive error by the use of contact lenses which change the cornea's shape.

Orthopedic Surgeon: Also referred to as an Orthopedist, he/she is a physician who specializes in Orthopedics i.e. diagnosing, treating, and managing the process of rehabilitation of patients suffering from disease or injury to the skeletal system.

Orthostatic Hypotension: A large drop in the blood pressure which occurs when a person stands up from a lying or seated position, which can result in dizziness, faintness, light-headedness, or an increase in the pulse.

Osteoblast: A cell which forms the minerals and tissue of the bone.

Osteocyte: A cell in the bone which maintains it as a living tissue.

Osteophyte: An abnormal, small and bony growth in the bone.

Otoacoustic Emissions (OAE): A test to check hearing, using a microphone put in the ear canal, that measures the sounds, or acoustic emissions, which are generated in the inner ear.


Pacemaker: An electronic device which regulates the heartbeat, which is implanted surgically into the chest and heart of a patient.

Pain Threshold: The point wherein a stimulus causes pain to be felt.

Palliative Treatment: A treatment that alleviates the symptoms of a disease, for example reducing pain, without curing it. The main purpose of this is improving the quality of life of the patient.

Pallidotomy: An operation wherein the globus pallidus, a part of the brain, is lesioned to improve symptoms like rigidity, tremor, and bradykinesia.

Palsy: The loss in the ability of moving a part of the body due to the paralysis of a group of muscles or a muscle.

Papillary Stenosis: A condition wherein the openings of the pancreatic ducts and bile ducts become narrow.

Parietal Cells: The cells located in the wall of the stomach which produce hydrochloric acid.

Parkinsonism: The term with which a group of disorders that have similar features are referred to. The four main symptoms are: tremor, postural instability, bradykinesia, and rigidity, which are brought about due to the loss of brain cells that produce dopamine.

Parosmia: An impairment of the olfactory senses which causes the individual to perceive odors that are non-existent.

Partial Colectomy: Surgically removing a portion of the large intestine.

Partial Mastectomy: A surgical procedure wherein a part of the breast is removed.

Patellar Tendonitis: An inflammation of the ligament of the patella, usually because of overuse.

Pathologist: A physician specializing in medical diagnosis by identifying diseases. He/she does this by studying tissues and cells under a microscope.

Pathology: The medical branch that deals with the study of the nature, causes and effects of various diseases.

Peak Flow Meter: A hand-held device that is inexpensive and portable, which is used for measuring the ability of blowing air from the lungs. Useful for checking the lung capacity of a patient, such as those afflicted with asthma.

Pepsin: An enzyme that is produced in the stomach for breaking down proteins.

Peptic Ulcer: An ulcer, generally caused by the Helicobacter pylori bacterium, which occurs in the lining of the stomach, esophagus, or duodenum. When it occurs in the stomach it is referred to as a gastric ulcer, and if in the duodenum, it is called a duodenal ulcer.

Pericardium: The membrane which the heart is surrounded by.

Perilymph Fistula: The leakage of the fluid of the inner ear into the middle ear which may be due to trauma of the head, barotrauma, or physical exertion.

Periodontal Diseases: Also referred to as gum diseases, these are serious infections caused by bacteria which damage the gums and the other tissues in the mouth that surround it.

Physical Education: See physical education definition.

Physical Fitness: See definition of physical fitness.

Psychology: See definition of psychology.


Q Fever: It is an acute type of zoonotic (transmitted from animals) disease caused by the Coxiella burnetti bacteria. Besides the onset of sudden fever, the other symptoms nclude malaise, pneumonia, and headache.

Qaly: This stands for Quality Adjusted Life Year, which means a year in a person's life being adjusted according to its quality. For example, a year of perfect health is regarded as equivalent to 1.0 QALY. Likewise, a year wherein the person is ill would have a reduced value. For instance, a year of being bedridden would be calculated as having 0.5 QALY.

Qualified Health Claim: A claim that is granted authorization by the FDA, or the US Food and Drug Administration, which must be corroborated by convincing scientific basis about the relationship between a particular food and a condition related to health or disease. For instance, a qualified health claim was announced by the FDA in 2004, which stated that the chances of getting coronary heart disease was reduced if foods containing omega-3 fatty acids were included in the diet.

Quadriparesis: The weakening of all the four limbs, both legs and both arms, for instance, as a result of muscular dystrophy.

Quadriplegia: All the four limbs being afflicted with paralysis, which can be caused due to an accident which damages the upper part of the spinal cord, or stroke.

Quinacrine: A drug used to treat malaria. In cytogenetics, the branch of medicine that deals with the cellular factors of heredity, it is used as a dye to stain chromosomes.

Quincke's Disease: An angioneurotic edema, which is a type of localized swelling that occurs in the deep layers of fatty tissue and skin.

Quinine: The original drug against malaria. The term has been derived from 'kina', a Peruvian Indian word, which means 'bark of the tree' pertaining to the chinchona tree.

Quinquagenarian: A person in his/her fifties.

Quintan Fever: A fever that recurs every five days, which is a characteristic of trench fever.


Radial Keratotomy (RK): A surgical method of correcting myopia by making incisions in the cornea in a radial pattern.

Radiation Therapy: Using radiation from neutron, X-rays, and various other sources to shrink tumors and kill cancerous cells.

Radiation Colitis: The colon getting inflamed due to radiation therapy.

Radical Mastectomy: Surgically removing the full breast, along with the ancillary lymph nodes, and the pectoral muscles.

Radical Prostatectomy: A surgical procedure wherein the prostate gland is removed along with the seminal vesicle glands that are attached to it.

Radiculopathy: A constriction of a nerve in the spinal column usually due to a slipped or herniated disc, which results in shooting pains.

Radioactivity: See what is Radioactivity.

Radioisotope: Injecting a radioactive substance into the body in order to make pictures with a nuclear scanner.

Radionuclide Scan: A small amount of a radioactive material injected into a vein in order to make an imaging scan. A machine checks the radioactivity levels in organs, which help in detecting tumors.

Radionuclide Ventriculography: A diagnostic method which is used for determining the size and shape of the chambers of the heart.

Range of Motion: Measuring the extent to which a joint can be moved, extended, or flexed.

Recommended Dietary Allowance (RDA): The recommended levels of essential nutrients that should be consumed by healthy people. This is set according to scientific basis by the Food and Nutrition Board.

Rectal Manometry: A test using a thin tube to which a balloon is attached which measures the movements and pressure of the sphincter and rectal muscles.

Rectocele: A condition wherein the lower wall of the vagina is weakened resulting in the rectum bulging into it.

Reflex Sympathetic Dystrophy Syndrome (RSDS): A condition that is chronic which is characterized by pain that is severe and felt like a burning sensation, pathological changes in skin and bone, profuse sweating, swelling of tissue, and sensitivity to touch. It is caused because of the impairment of a nerve at the location of an injury, usually in the legs or arms.

Reflux: Also referred to as regurgitation, this is a condition wherein small amounts of the contents of the stomach, or gastric juices, return into the esophagus, and even into the mouth.

Reflux Esophagitis: Inflammation of the esophagus because of the contents of the stomach returning into it.

Refractive Error: The degree at which light reaches the back part of the eye; it includes hyperopia, astigmatism, and myopia.

Regional Anesthetic: An anesthetic that is used to benumb a part of the body.

Regurgitation, Heart: A defective valve of the heart causing blood to flow backward.

Resting Tremor: A tremor in a limb increasing when it is at rest.

Rotator Cuff Tear: See what is Rotator Cuff Tear in Shoulder.


Sacroiliac Joint: A joint that lies betwixt the sacrum and ilium. It is a flat bone that helps to compose the pelvis.

Saline Solution: A solution made up of distilled water and sodium chloride.

Saliva: A clear fluid that is secreted by the mucous glands and salivary glands located in the mouth. It helps to moisten the mouth, starting the process of digesting starches.

Salpingectomy: Surgically removing either one or both the fallopian tubes.

Salpingo-Oophorectomy: Surgically removing both the fallopian tubes as well as the ovaries.

Saturated Fat: Fat which is found in the meat and skin of animals, dairy products, and certain vegetables.

Scapula: Also referred to as the shoulder blade, in human beings it is the triangular flat bones on each side of the shoulders.

Sciatica: A condition wherein there is acute and spasmodic pain along the sciatic nerve, which may be caused either by irritation of the nerve, or direct pressure on it.

Sclerotherapy: A method of arresting bleeding in the upper gastrointestinal tract. An endoscope is used to insert a needle through it to place clotting agents where there is bleeding.

Scotoma: A visual disorder wherein there is complete or partial loss of vision in an area of the eye, which is surrounded by an area wherein there is normal vision.

Seborrhea: A disease that affects the sebaceous glands which results in the excessive production of sebum, or a deterioration in its quality, which has the effect of creating an oily coat, scales, or crusts on the surface of the skin.

Sebum: An oily substance secreted by the sebaceous glands located in the skin.

Secretin: A hormone that is secreted in the duodenum. It results in stimulating the stomach to produce pepsin, the pancreas to produce digestive juices, and the liver to secrete bile.

Sedona Method: See what is Sedona method.

Sever's Disease: Also referred to as Calcaneal Apophysitis, this is a condition that affects children who are between 9-14 years of age, whose bone structure is not fully developed yet. It is characterized by tenderness and soreness in the heels, which can occur on children in this age group participating in sports like basketball, soccer, and other such activities which involve jumping and running.

Slipped Capital Femoral Epiphysis: This is a condition which affects children, wherein the ball, or the head, of the thigh bone, also called femoral head, slips out of the neck of the thigh bone, resulting in the hip joint becoming stiff and painful.

Stress: See definition of stress.


Tamoxifen: A drug that is an antagonist of estrogen, which is used for treating breast cancer.

Technetium Bone Scan: A radiological method of detecting stress fractures.

Telemetry Unit: A small-sized transmitter which has wires that place ECG patches on the chest. The unit then sends the information it detects about the heart to health care professionals, by way of radio transmission, for evaluation.

Tendonitis: An inflammation of either the covering of a tendon or the tendon itself. It is usually caused by repeated stress on the tendon which aggravates it.

Thallium Stress Test: A diagnostic test wherein a radioactive substance is introduced in the blood, the progress of which is tracked by X-ray pictures.

Thomas's Test: An examination for detecting whether a patient has fixed hip deformity.

Thoracotomy: A surgical incision made in the wall of the chest in order to open up the pleural cavity. It is useful for viewing the lung, to confirm cancer, or to find out the source of bleeding in the event of trauma to the chest.

Thrombolysis: The process wherein blood clots are dissolved or broken down.

Thrombolytic Drugs: The medications that are used for breaking down blood clots.

Thrombosis: A condition wherein a blood clot forms in the heart or in a blood vessel.

Thyroplasty: Also referred to a Laryngeal Framework Surgery, it is a surgical method used for improving the voice by making alterations to the larynx's cartilages.

Thyroxine (T4): This is a hormone that the thyroid gland secretes for regulating the metabolism.

Tinnitus (Ringing Ear): A ringing, booming or buzzing sensation in the ears, which is usually a symptom of an infection of the ear, or the development of an impairment of hearing, or Ménière's disease.


Ubidecarenone: Also referred to as Coenzyme Q10, this is a compound that is required for an enzyme to function properly, which is a protein which quickens the rate at which chemical reactions occur in the body. It is used for producing energy in order to fuel the growth of cells and their maintenance.

Ulcer: A lesion that forms on the skin or the mucous membrane, like the lining of the stomach or the duodenum, which can become suppurated and lead to the necrosis of the tissue surrounding it.

Ulocarcinoma: A cancer which affects the gums, usually associated with using chewing tobacco.

Ultraviolet Radiation: Invisible rays that emanate from the sun. Exposure to UV rays can result in damaging the skin and even lead to melanoma and other kinds of skin cancer.

Upper GI Endoscopy: The internal examination of the stomach, esophagus, and duodenum with the help of an endoscope.

Upper Limb Tension (ULTT): A test used for assessing pain.

Urea Breath Test: A test used for detecting infection caused by the Helicobacter pylori bacterium. Breath samples are measured for the presence of urease, which is an enzyme that is produced by the H. pylori.

Urge Incontinence: Urinary incontinence caused by the involuntary contractions of the bladder, which results in an urgent requirement for urination, and is usually accompanied by sudden evacuation of urine. This condition usually develops due to aging.

Urinary Retention: The inability of emptying the bladder.

Usher's Syndrome: A hereditary condition which causes deafness and blindness. A person afflicted with this condition essentially loses his/her peripheral vision progressively, usually starting with night blindness, which is also accompanied by congenital loss of hearing.


Vagotomy: A surgical procedure used for cutting the vagus nerve so that the stomach produces less acid.

Valgus Deformity: This is a condition wherein the distal portion of a joint or bone is angled outward.

Valvoplasty: The reparation of the heart valve through surgery.

Varices: Abnormally twisted or enlarged blood vessel, like those that are formed in the esophagus due to cirrhosis.

Varicose Vein: A condition wherein a vein, usually in the legs, becomes abnormally dilated and twisted, resulting in pain. This is usually caused by the valves located in the vein not working properly or the weakening of the walls of the vein.

Varus Deformity: This is a condition wherein the distal portion of a joint or bone is angled inward.

Vasodepressors: A drug that increases the blood pressure.

Vasodilator: A medication that is used to expand or dilate blood vessels.

Velocardiofacial Syndrome: A genetic condition which is characterized by heart defects, cleft palate, a distinctive facial appearance, feeding and speech problems, and minor problems in the ability to learn. The name has been derived from the Latin terms velum, which means palate, cardia, meaning the heart, and facies, which refers to the face.

Ventricular Fibrillation: A condition wherein there is unsynchronized and rapid contractions of the ventricles of the heart, which results in an impairment of the ability of pumping blood into the body.

Vestibular Neuronitis: A condition wherein the vestibular nerve is infected. This the nerve connecting the internal ear to the brain.

Vestibular System: The part of the internal ear, containing the semicircular canals, saccule, and utricle, which enables the body to maintain its balance, posture, and orientation. It also helps in regulating locomotion and other bodily movements.

Vestibule: The bony cavity located in the inner ear.

Vibrotactile Aids: Mechanical devices that help people afflicted with deafness in detecting and interpreting sound via the sense of touch.

Villi: Very small, hair-like structures that line the small intestine which help in absorbing nutrients from food.

Viral Hepatitis: A condition wherein the liver becomes inflamed due to being infected by any of five viruses, known as hepatitis A, hepatitis B, hepatitis C, D and E.

Vitrectomy: A surgical procedure to remove blood that accumulates sometimes behind the eyes of people afflicted with eye disease.

Vitreous Body: The jelly-like, clear substance which the center of the eye is filled with.

Volvulus: A condition wherein the stomach or the intestines are twisted abnormally, resulting in the blood supply being cut off to the area, or in obstruction in the intestines.


Waardenburg Syndrome: A hereditary disorder characterized by deafness, a white shock of hair in the front of the head, different coloring of the iris of each eye, white colored eyelashes, and the inner corners of the eyes being wide-set.

Wagner Syndrome: Also called Stickler syndrome, this is a fairly common hereditary disorder typified by extreme flexibility of the joints, distinctive facial features like flattened cheekbones and bridge of the nose, loss of hearing, and nearsightedness.

Walking Pneumonia: See what is Walking Pneumonia.

Walleye: A condition wherein there is leukoma, or white opacity, of the cornea, exotropia, or divergent strabismus, wherein the eyes are directed outward, or away from the nose, and staring, large eyes.

Warfarin: An anticoagulant medication used for preventing clotting of blood, and treating overly thickening of blood and blood clots. It is prescribed for reducing the risk of clots causing heart attacks or stroke.

Watermelon Stomach: Red sores that occur in parallel lines in the stomach which resemble the stripes on the surface of the watermelon.

Weaver Syndrome: This is a genetic condition wherein growth is accelerated and the age of the bone is abnormally advanced which is manifested at birth, abnormal increase in the tone of the muscles, or hypertonia, unusual appearance of the face and cranium, low-pitched hoarse cry, the inability to open the fingers fully, or camptodactyly.

Wedge Resection of the Lung: Surgically removing a small section of the lung, usually performed in order to carry out a biopsy of the lung.

Wet Brain: Also referred to as Cerebral Edema, it is a condition wherein excessive fluid accumulates in the brain.

Whiplash Injury: An overextension or hyperextension injury of the neck, usually caused due to the neck suddenly snapping when a fast-moving vehicle brakes suddenly, or is involved in a crash.

Whole Blood: Blood that contains all its elements, e.g. white and red blood cells, plasma, platelets, and so on. Whole blood is usually used for blood transfusions.


Xanax: Also referred to as Alprazolam, this is a sedative used for treating panic attacks, anxiety, muscle spasms, and insomnia.

Xanthelasma: Tiny, yellowish growths on the eyelids, which are caused by small fat deposits under the skin, due to hyperlipidemia, or abnormally elevated levels of fat in the blood.

Xanthine: A substance present in caffeine, theophylline, and theobromine. It is found in coffee, tea, and cola beverages.

Xanthoma: Firm, yellowish nodules that occur in skin, which is usually indicative of an underlying illness, like diabetes, hyperlipidemia, and so on.

Xanthopsia: A type of defect in the vision wherein objects appear to be unnaturally over-painted. Yellow is the color associated with xanthopsia.

Xenobiotic: Any substance present in an organism that is not produced normally by it, or is not expected to be found in it.

Xeroderma: A condition wherein the skin is abnormally dry, usually due to a lack of vitamin A, overexposure to the sun, systemic illness, or certain types of medications.

Xerostomia: A condition that causes dry mouth, which can be caused by various factors such as diabetes, rheumatoid arthritis, drugs used for treating depression, radiation therapy for the cancer of the throat or mouth, HIV infection, and kidney failure.

X, Factor: This is a substance that is present in blood which is essential for the process of normal clotting. It is produced in the liver, and it requires vitamin K.

Xiphoid Process: Also referred to as the ensiform cartilage, it is the cartilaginous attachment found in the lower part of the sternum or breastbone. It usually becomes bony, or ossified, in adults.


YAG Laser Surgery: Using YAG, or Yttrium-Aluminum-Garnet, laser to perform surgery.

Yama: Also referred to as Caspase 3, this is an enzyme that has an important function in the programmed death of cells.

Yaws: A chronic disease, caused by a spirochete organism, that occurs commonly in humid, tropical regions. It is characterized by small protrusions on the face, feet, hands, and genital region.

Yeast Infection: Yeast overgrowth can result in yeast rash of the skin, thrush in the mouth, esophagus, digestive tract, vagina, and elsewhere in the body. Infections caused by yeast usually occur in moist parts of the body.

Yttrium: An uncommon elemental metal, the radioactive form of which is used in some kinds of immunotherapy, and radiation therapy.


Zaleplon: A hypnotic sedative, closely related to benzodiazepines, which affects the central nervous system.

Zenker's Diverticulum: Sacs that form in the esophagus due to an increase in pressure either inside it or around it.

Zellweger Syndrome: Also referred to as Cerebrohepatorenal Syndrome, this is a hereditary disorder wherein there is an absence or reduction of peroxisomes - cell structures that help the body to get rid of toxic matter - in the cells of the brain, liver, and kidneys.

Zidovudine: Formerly known as Azidothymidine, or AZT, this is a drug used for treating AIDS.

Zinsser Disease: Also referred to a Brill-Zinsser disease, it is a recrudescence of the epidemic form of typhus long after the first attack. Rickettsia prowazekii, which is the bacteria that causes typhus, can remain dormant for a number of years, and get reactivated when the host's defenses are low, causing a recurrence of typhus.

Zigote Intrafallopian Transfer (ZIFT): An infertility treatment which wherein the eggs are removed from the ovaries of a woman and fertilized with the sperm from either her partner or from a donor, in the laboratory. Then either one or more of these fertilized eggs are inserted into the fallopian tubes.

Zollinger-Ellison Syndrome: This is a condition that is caused by a gastrinoma, which is a tumor, that usually occurs in the pancreas. The hormone gastrin is secreted by this tumor, which results in an increase in the production of gastric acid. This leads to recurrent and severe ulcers forming in the upper parts of the small intestine (the duodenum as well as the jejunum), the esophagus, and the stomach.

Zolmitriptan: A drug, which belongs to the tryptamine group of drugs, used for treating migraine.

Zoonosis: A disease that occurs in animals which humans can get infected with. Some of these diseases are: rabies, transmitted by a bite form an infected animal; anthrax, which usually affects ruminants like sheep, cattle, horses, and goats, which humans can get by coming into contact with animals that are infected; psittacosis, an infection that is akin to influenza, which humans can get by coming in contact with the droppings of the birds infected by it.

Zygomycosis: A dangerous disease which is spread by a waterborne fungus.

See more medical terms definitions in:Also see Medical abbreviations and acronyms for medical terms.