Medical Glossary

Calcification- the depositing of calcium salts in the body, which occurs normally in teeth and bones but abnormally in injured muscles and narrowed arteries

Calcitonin- a hormone made in the thyroid gland that controls calcium levels in the blood by slowing the loss of calcium from bones; used to treat hypercalcemia (excess calcium in the blood)

Calcium- a plentiful mineral in the body and the basic component of teeth and bones; essential for cell function, muscle contraction, transmission of nerve impulses, and blood clotting

Calcium channel blocker- a drug used to treat chest pain, high blood pressure, and irregular heartbeat by preventing the movement of calcium into the muscle

Callus- a thickened area of skin due to consistent pressure or friction, or the area around a bone break where new bone is formed

Calorie- a unit that is used to measure the energy content in food

Canal- a tunnel-like passage

Cancer- a group of diseases in which cells grow unrestrained in an organ or tissue in the body; can spread to tissues around it and destroy them or be transported through blood or lymph pathways to other parts of the body

Cancer staging- a method to determine how much a cancer has developed

Candidiasis- a yeast infection caused by the fungus Candida albicans; occurs most often in the vagina, but also in the mouth, on moist skin, or on the penis

Canker sore- small, painful sore that usually occurs on the inside of the lip or cheek, or sometimes under the tongue; caused by bacteria, irritation of the area, stress, or allergies

Capillary- a tiny blood vessel that connects the smallest arteries to the smallest veins and allows exchange of oxygen and other materials between blood cells and body tissue cells

Carbohydrate- a substance, mainly sugar and starch, that is a main source of energy for the body and is found in sources such as cereals, breads, pastas, grains, and vegetables

Carbon dioxide- a colorless, odorless gas present in small amounts in the atmosphere and formed during respiration

Carcinogen- anything that can cause cancer

Carcinoma- a cancer that occurs on the surface or lining of an organ

Cardiac arrest- the sudden cessation of the heart's pumping action, possibly due to a heart attack, respiratory arrest, electrical shock, extreme cold, blood loss, drug overdose, or a severe allergic reaction

Cardiogenic shock- a severely dangerous condition involving decreased blood output from the heart, usually as a result of a heart attack

Cardiomegaly- a condition marked by enlargement of the heart, either because of a thickened heart muscle or an enlarged heart chamber; usually a result of the heart having to work harder than normal, as occurs with high blood pressure

Cardiomyopathy- a disease of the heart muscle that results in decreased output and reduced blood flow

Cardiopulmonary resuscitation- the administration of heart compression and artificial respiration to restore circulation and breathing

Cardiovascular system- the heart and blood vessels that are responsible for circulating blood throughout the body

Carditis- inflammation of the heart

Carotene- an orange pigment present in colored plants such as carrots that is converted by the body to the essential nutrient vitamin A

Carotid arteries- four main arteries that carry blood to the head and neck

Carpal bones- eight bones that together make the wrist

Carpal tunnel syndrome- a condition in which pressure on the median nerve in the wrist causes soreness, tingling, and numbness in the thumb and index and middle fingers

Cartilage- a connective tissue (softer than bone) that is part of the skeletal system, including the joints

Cast- a hard plaster or fiberglass shell that molds to a body part such as an arm and holds it in place for proper healing

Cataract- a disorder in which the lens of the eye becomes less transparent and in some cases a milky white, making vision less clear

Catheter- a hollow, flexible tube inserted into the body to put in or take out fluid, or to open up or close blood vessels

Catheterization- a technique in which a hollow, flexible tube is used to drain body fluids (such as urine), to introduce fluids into the body, or to examine or widen a narrowed vein or artery

CAT scanning- see Computed tomography scanning

Cat-scratch fever- an illness transmitted to humans through a cat's bite or scratch, which is thought to be caused by an unidentified bacteria; characterized by a swollen lymph node or blister near the bite or scratch, fever, rash, and headache; most commonly occurring in children

Cauliflower ear- a deformed ear caused by repeated injury

Cauterization- the use of heat, an electric current, or a chemical to destroy tissue or stop bleeding

Cecum- the beginning of the large intestine, which is connected to the appendix at its lower end

Cell- the tiny structures that make up all the tissues of the body and carry out all of its functions

Cellulitis- a skin infection caused by bacteria (usually streptococci); can lead to tissue damage and blood poisoning if untreated; characterized by fever, chills, heat, tenderness, and redness

Central nervous system- the brain and spinal cord Cerebellum- a region of the brain located at the back; responsible for coordination of movement and maintaining balance

Cerebral palsy- a group of disorders of movement and posture resulting from damage to the brain early in a child's development; causes muscle weakness, difficulty coordinating voluntary movements, and sometimes complete loss of motion

Cerebrospinal fluid- a clear, watery fluid circulating in and around the brain and spinal column, which contains glucose, proteins, and salts for nutrition

Cerebrovascular disease- a disease affecting any artery supplying blood to the brain; may cause blockage or rupture of a blood vessel, leading to a stroke

Cerebrum- the largest part of the brain and the site of most of its activity, including sensory and motor functions

Cervical cap- a small rubber cup that is placed tightly over the cervix to prevent pregnancy

Cervical dysplasia- changes that occur in the cells on the surface of the cervix that usually precede the stages of cancer

Cervical incompetence- a weakness of the neck of the uterus, which can lead to spontaneous abortion due to an inability to support the weight of the fetus

Cervical smear- a procedure in which cells are scraped off of the cervix and examined to detect changes that might precede the stages of cancer; also called a Pap smear

Cervicitis- inflammation of the cervix Cervix- a small, round organ making up the neck of the uterus and separating it from the vagina

Cesarean section- an operation performed to remove a fetus by cutting into the uterus, usually through the abdominal wall

Chancre- a painless sore that has a thick, rubbery base and a defined edge; usually occurs on the genitals after the contraction of the sexually transmitted disease syphilis

Chemotherapy- the treatment of infections or cancer with drugs that act on disease-producing organisms or cancerous tissue; may also affect normal cells

Chickenpox- a contagious disease that causes a rash and a fever; most commonly occurs during childhood

Chlamydia- microorganisms that cause several human infections and can be transmitted sexually

Cholecystectomy- the surgical removal of the gallbladder

Cholera- a bacterial infection of the small intestine that causes severe watery diarrhea, dehydration, and possibly death

Cholesterol- a substance in body cells that plays a role in the production of hormones and bile salts and in the transport of fats in the bloodstream

Chondritis- inflammation of cartilage

Chondroma- a noncancerous tumor that occurs in cartilage

Chondromalacia patellae- painful damage to the cartilage behind the kneecap

Chondrosarcoma- a cancerous cartilage tumor that develops inside of bone or on its surface

Chorionic villus sampling- a method of diagnosing fetal defects in which a small amount of tissue is taken from the placenta and analyzed for abnormalities

Choroiditis- inflammation of the blood vessels behind the retina that line the back of the eye

Chromosome analysis- examination of a person's chromosomes either to determine if that person has an abnormality or to investigate one

Chronic- describes a disorder that continues for a long period of time

Chronic obstructive lung disease- a combination of the lung diseases emphysema and bronchitis, characterized by blockage of airflow in and out of the lungs

Cilia- tiny, hairlike structures on the outside of some cells, providing mobility

Circumcision- the surgical removal of the foreskin of the penis

Cirrhosis of the liver- gradual loss of liver function due to cell damage and internal scarring

Claudication- a cramping pain in one or both legs while walking, which can cause limping

Claustrophobia- fear of being confined in an enclosed or crowded space

Clavicle- the medical term for the collarbone

Cleft lip- a birth defect in which the upper lip is split vertically, extending into one or both nostrils

Cleft palate- a birth defect in which the roof of the mouth is split, extending from behind the teeth to the nasal cavity; often occurs with other birth defects such as cleft lip and partial deafness

Clinical trial- carefully monitored and planned testing of a new drug or treatment

Clitoris- a small female organ located near the opening of the vagina that swells when sexually aroused

Clone- an exact copy of a gene, cell, or organism Closed fracture- a bone break that does not break the skin

Clotting factor- a substance in the blood that is needed for blood to harden and stop a wound from bleeding

Clubfoot- a genetic disorder in which the foot is twisted and misshapen

Cluster headache- severe pain that occurs suddenly and affects one side of the head, including the face and neck

CNS- see Central nervous system

Coagulation- a process that plays a large role in the hardening and thickening of blood to form a clot

Cocarcinogen- a substance that does not cause cancer by itself, but increases the effect of a substance that does cause cancer

Coccyx- four fused bones that form a triangular shape at the base of the spine (also known as the tailbone)

Cochlea- a coiled organ in the inner ear that plays a large role in hearing by picking up sound vibrations and transmitting them as electrical signals

Coitus- sexual intercourse

Cold sore- a small blister anywhere around the mouth that is caused by the herpes simplex virus

Colectomy- the complete or partial surgical removal of the large intestine (the colon), usually as treatment of a cancerous tumor or a narrowing and blockage of the intestine

Colic- waves of pain in the abdomen that increase in strength, disappear, and return; usually caused by a stone blocking a bile or urine passageway or an intestinal infection

Colitis- inflammation of the large intestine (the colon), which usually leads to abdominal pain, fever, and diarrhea with blood and mucus

Collapsed lung- a condition in which all or part of a lung cannot expand and fill with air

Colon- the main part of the large intestine, between the cecum and the rectum

Colonoscopy- investigation of the inside of the colon using a long, flexible fiberoptic tube

Color blindness- any vision disorder in which the person sees colors abnormally, has trouble distinguishing between them, or cannot see them at all

Colostomy- a surgical procedure in which some part of the colon is cut and moved to the surface of the abdomen so that feces can be passed into a bag worn outside of the body

Coma- a condition in which the area of the brain involved in maintaining consciousness is somehow affected, resulting in a state of unconsciousness in which the patient does not respond to stimulation

Comminuted fracture- a crushed or shattered bone

Common cold- an infection caused by a virus, which results in an inflamed lining of the nose and throat; characterized by a stuffy and runny nose and, sometimes, a sore throat

Communicable disease- a disease that can be passed from one individual to another

Compound fracture- a bone break that breaks the skin

Compression fracture- a break in a short bone in which its soft tissue is crushed

Computed tomography scanning- a technique for producing cross-sectional images of the body in which X-rays are passed through the body at different angles and analyzed by a computer; also called CT scanning or CAT scanning

Concussion- disturbance of electrical activity in the brain due to a blow to the head or neck, causing temporary loss of consciousness

Congenital- present or existing at the time of birth

Congestive heart failure- inability of the heart to efficiently pump blood through the body, causing buildup of blood in the veins and of other body fluids in tissue

Conjunctiva- the clear membrane covering the white of the eye and the inside of the eyelid that produces a fluid that lubricates the cornea and eyelid

Conjunctivitis- inflammation of the conjunctiva; commonly called pinkeye

Connective tissue- strong tissue that connects and supports body structures

Constipation- difficult or infrequent bowel movements of hard, dry feces Contraindication- an aspect of a patient's condition that makes the use of a certain drug or therapy an unwise or dangerous decision

Contusion- damage to the skin and underlying tissue as a result of a blunt injury; a bruise

Corn- a thickened callus on the foot that is caused by an improperly fitting shoe

Cornea- the clear, dome-shaped front portion of the eye's outer covering

Coronary- describes structures that encircle another structure (such as the coronary arteries, which circle the heart); commonly used to refer to a coronary thrombosis or a heart attack

Coronary arteries- the arteries that branch off from the aorta and supply oxygen-rich blood to the heart muscle

Coronary artery bypass surgery- an operation in which a piece of vein or artery is used to bypass a blockage in a coronary artery; performed to prevent myocardial infarction and relieve angina pectoris

Coronary heart disease- disorders that restrict the blood supply to the heart, including atherosclerosis

Coronary thrombosis- the blockage of a coronary artery by a blood clot

Corpuscle- a tiny, rounded structure in the body, such as a red or white blood cell

Corticosteroids- synthetic drugs that are used to replace natural hormones or to suppress the immune system and help prevent inflammation

CPR- see Cardiopulmonary resuscitation

Creatinine- a waste product that is filtered from the blood by the kidneys and expelled in urine

Croup- a usually mild and temporary condition common in children under the age of 4 in which the walls of the airways become inflamed and narrow, resulting in wheezing and coughing

Cruciate ligaments- two ligaments in the knee that cross each other and help stabilize the knee joint

CT scanning- a procedure that uses X-rays and computers to create cross-sectional images of the body to diagnose and monitor disease

Culture- the artificial growth of cells, tissue, or microorganisms such as bacteria in a laboratory

Curettage- the use of a sharp, spoonlike instrument (a curet) to scrape away tissue that is abnormal or to obtain a sample that can be analyzed

CVS- see Chorionic villus sampling

Cyanosis- a bluish discoloration of the skin, caused by low levels of oxygen in the blood

Cyst- a lump filled with either fluid or soft material, occurring in any organ or tissue; may occur for a number of reasons but is usually harmless unless its presence disrupts organ or tissue function

Cystectomy- surgical removal of the bladder; the bladder is often replaced with a short length of small intestine

Cystic fibrosis- an inherited disorder in which the lungs are prone to infection, and fats and other nutrients cannot be absorbed into the body

Cystoscopy- examination of the urethra and bladder using a long, thin, fiberoptic tube

Cystostomy- the surgical placement of a drainage opening in the bladder