MEDICAL DICTIONARY
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Click on the alphabet and there you go!

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

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C: Cystosine, one member of the G-C (guanine-cytosine) pair of bases in DNA.

C-section: Short for Caesarian section.

C/S: Abbreviation for Caesarian section. Why the slash (/) is between the "C" and the "S", who knows?

CABG (Coronary Artery Bypass Graft): Coronary artery disease develops because of hardening of the arteries (atherosclerosis) that supply blood to the heart muscle. Diagnostic tests include EKG, stress test, echocardiography, and coronary angiography. CABG surgery is advised for selected groups of patients with significant narrowings and blockages of the heart arteries (coronary artery disease) to create new routes around narrowed and blocked arteries, permitting increased blood flow to deliver oxygen and nutrients to the heart muscles. The bypass graft for a CABG can be a vein from the leg or an inner chest wall artery. CABG surgery is performed about 350,000 times annually in the United States, making it one of the most commonly performed major operations.

Caesarian section: Procedure in which an infant, rather than being born vaginally, is surgically removed from the uterus. Also referred to as a C section. As the name "Caesarian" suggests, this is not exactly a new procedure. It was done in ancient civilizations upon the death of a near-full-term pregnant woman to salvage the baby. Julius Caesar (or one of his predecessors) was born by this procedure. Hence, the name "Caesarian". The term "section" in surgery refers to the division of tissue. What is being divided here is the abdominal wall of the mother as well as the wall of the uterus in order to extract the baby. In Shakespeare’s "Macbeth" the Witches’ prophecy was that "...none of woman born/ Shall harm Macbeth" (IV.i). Unfortunately for Macbeth, the Scottish nobleman Macduff was "from his mother’s womb/ Untimely ripped." and thus not naturally "born of woman"(V.vii). Macduff was the only agent capable of destroying Macbeth. He killed Macbeth in battle.

Calcific bursitis: A bursa is a thin fluid-filled sac that reduces friction forces between tissues of the body. Chronic (repeated of long-standing) inflammation of the bursa (bursitis) can lead to calcification of the bursa. This is referred to as "calcific bursitis." The calcium deposition (calcification) can occur as long as the inflammation is present.

Calcium: A mineral found mainly in the hard part of bones. Bone is a storage area for calcium. Calcium is added to bone by cells called osteoblasts. It is removed from bone by cells called osteoclasts. Calcium is not just essential for healthy bones. It is also important for muscle contraction, heart action and normal blood clotting. A low blood calcium (hypocalcemia) makes the nervous system highly irritable with tetany (spasms of the hands and feet, muscle cramps, abdominal cramps, overly active reflexes, etc.). Chronic calcium deficiency contributes to poor mineralization of bones, soft bones (osteomalacia) and osteoporosis; and, in children, rickets and impaired growth. Food sources of calcium include dairy foods, some leafy green vegetables such as broccoli and collards, canned salmon, clams, oysters, calcium-fortified foods, and tofu. According to the National Academy of Sciences, adequate intake of calcium is 1 gram daily for both men and women. The upper limit for calcium intake is 2.5 grams daily. Overly high intake of calcium (hypercalcemia) may cause muscle weakness and constipation, affect the conduction of electrical impulses in the heart (heart block) lead to calcium stones (nephrocalcinosis) in the urinary tract, impair kidney function, and interfere with the absorption of iron predisposing to iron deficiency.

Calcium deficiency: A low blood calcium (hypocalcemia) makes the nervous system highly irritable with tetany (spasms of the hands and feet, muscle cramps, abdominal cramps, overly active reflexes, etc.). Chronic calcium deficiency contributes to poor mineralization of bones, soft bones (osteomalacia) and osteoporosis; and, in children, rickets and impaired growth. Food sources of calcium include dairy foods, some leafy green vegetables such as broccoli and collards, canned salmon, clams, oysters, calcium-fortified foods, and tofu. According to the National Academy of Sciences, adequate intake of calcium is 1 gram daily for both men and women. The upper limit for calcium intake is 2.5 grams daily.

Calcium excess: Overly high intake of calcium (hypercalcemia) may cause muscle weakness and constipation, affect the conduction of electrical impulses in the heart (heart block) lead to calcium stones in the urinary tract, impair kidney function (through nephrocalcinosis), and interfere with the absorption of iron predisposing to iron deficiency. According to the National Academy of Sciences, adequate intake of calcium is 1 gram daily for both men and women. The upper limit for calcium intake is 2.5 grams daily.

Callus: (1) A callus or callosity is a localized firm thickening of the upper layer of skin as a result of repetitive friction. (2) A callus is the hard new bone substance that forms in an area of bone fracture. It is part of the bone repair process.

Cancer: Also called malignancy. Cancer refers to a abnormal growths which have a tendency to grow uncontrolled and metastasize. It can involve any tissue of the body and can have many different forms in each body area. Cancer is a group of more than 100 different diseases. Benign tumors are not cancer; malignant tumors are cancer. Most cancers are named for the type of cell or the organ in which they begin. When cancer spreads (metastasizes), the new tumor has the same name as the original (primary) tumor. Skin cancer is the most common type of cancer for both men and women. The second most common cancer in men is prostate cancer, in women it is breast cancer. Lung cancer is the leading cause of death from cancer for both men and women in the U.S. Cancer is NOT contagious.

Cancer, bladder: Cancer of the organ responsible for temporarily holding urine after it leaves the kidneys. The most common warning sign of cancer in the bladder (the hollow organ in the lower abdomen that stores urine) is blood in the urine. The diagnosis of bladder cancer is supported by findings of the medical history and examination, blood, urine, and x-ray tests, and confirmed with a biopsy (usually during a cystoscope exam).

Cancer, bone: Cancer of the skeleton. Cancers that begin in bone are rare but it is not unusual for cancers to spread (metastasize) to bone from other parts of the body. This is not called bone cancer, but is named for the organ or tissue in which the cancer begins. Pain is the most frequent symptom of cancer of the bone. Diagnosis of cancer of the bone is supported by findings of the medical history and examination, blood and x-ray tests and confirmed with a biopsy.

Cancer, brain: Cancer of the central information processing center of the body. Tumors in the brain can be malignant or benign and can occur at any age. Primary brain tumors initially form in the brain tissue. Secondary brain tumors are cancers that have spread to the brain tissue (metastasized) from elsewhere in the body.

Cancer, breast: Cancer of the tissue containing or involving the milk glands (mammary tissue). Breast cancer is diagnosed with self- and physician- examination of the breasts, mammography, ultrasound testing, and biopsy. There are many types of breast cancer that differ in their capability of spreading to other body tissues (metastasis). Treatment of breast cancer depends on the type and location of the breast cancer, as well as the age and health of the patient. The American Cancer Society recommends that a woman should have a baseline mammogram between the ages of 35 and 40 years. Between 40 and 50 years of age mammograms are recommended every other year. After age 50 years, yearly mammograms are recommended.

Cancer, causes: Cancer is a group of more than 100 different diseases. Benign tumors are not cancer; malignant tumors are cancer. Most cancers are named for the type of cell or the organ in which they begin. When cancer spreads (metastasizes), the new tumor has the same name as the original (primary) tumor. Skin cancer is the most common type of cancer for both men and women. The second most common cancer in men is prostate cancer, in women it is breast cancer. Lung cancer is the leading cause of death from cancer for both men and women in the U.S. Cancer is NOT contagious.

Cancer, cervix: Cancer of the entrance to the womb (uterus). Regular pelvic exams and Pap testing can detect precancerous changes in the cervix. Precancerous changes in the cervix may be treated with cryosurgery, cauterization, or laser surgery. The most common symptom of cancer of the cervix is abnormal bleeding. Cancer of the cervix can be diagnosed using a Pap test or other procedures that sample the cervix tissue. Cancer of the cervix requires different treatment than cancer that begins in other parts of the uterus.

Cancer, colon: A malignant tumor arising from the inner wall of the large intestine. The third leading cause of cancer in males, fourth in females in the U.S. Risk factors for cancer of the colon and rectum (colorectal cancer) include heredity, colon polyps, and long standing ulcerative colitis. Most colorectal cancers develop from polyps. Removal of colon polyps can prevent colorectal cancer. Colon polyps and early cancer can have no symptoms. Therefore, regular screening is important. Diagnosis can be made by barium enema or by colonoscopy with biopsy confirmation of cancer tissue. Surgery is the most common treatment for colorectal cancer.

Cancer, colon: screening and surveillance: Colon cancer is both preventable and curable. It is preventable by removing precancerous colon polyps. It is curable if early cancer is surgically removed before cancer spread to other parts of the body. Therefore, if screening and surveillance programs were practiced universally, there would be a major reduction in the incidence and mortality of colon cancer.

Cancer detection: Methods used to find cancer in persons who may or may not have symptoms. Symptoms of cancer are abnormal sensations or conditions that persons can notice that are a result of the cancer. It is important to your doctor for regular checkups and not wait for problems to occur. But you should also know that the following symptoms may be associated with cancer: changes in bowel or bladder habits, a sore that does not heal, unusual bleeding or discharge, thickening or lump in the breast or any other part of the body, indigestion or difficulty swallowing, obvious change in a wart or mole, or nagging cough or hoarseness. These symptoms are not always a sign of cancer. They can also be caused by less serious conditions. Only a doctor can make a diagnosis. It is important to see a doctor if you have any of these symptoms. Don’t wait to feel pain. Early cancer often does not cause pain.

Cancer, esophagus: Cancer of the swallowing tube that passes from the throat to the stomach. The risk of cancer of the esophagus is increased by long-term irritation of the esophagus, such as with smoking, heavy alcohol intake, and Barrett’s esophagitis. Cancer of the esophagus can cause difficulty and pain with swallowing solid food. Diagnosis of esophageal cancer can be made by barium x-ray of the esophagus, and confirmed by endoscopy with biopsy of the cancer tissue.

Cancer, gastric: Cancer of the stomach, the major organ that holds food for digestion. Stomach cancer (gastric cancer) can develop in any part of the stomach and spread to other organs. Stomach ulcers do not appear to increase a person’s risk of developing stomach cancer. Symptoms of stomach cancer are often vague, such as loss of appetite and weight. The cancer is diagnosed with a biopsy of stomach tissue during a procedure called an endoscopy.

Cancer, Hodgkin’s disease (adult): A type of lymphoma (cancer of the lymphatic system). The most common symptom of Hodgkin’s disease is a painless swelling in the lymph nodes in the neck, underarm, or groin. Hodgkin’s disease is diagnosed when abnormal tissue is detected by a pathologist after a biopsy of an enlarged lymph node. Treatment usually includes radiation therapy or chemotherapy. Regular follow-up examinations are important after treatment for Hodgkin’s disease. Patients treated for Hodgkin’s disease have an increased risk of developing other types of cancer later in life, especially leukemia.

Cancer, kidney: Cancer of the major organ responsible for the removal from the blood of the toxins of body metabolism—the kidney. Childhood kidney cancer is different from the adult kidney cancer. The most common symptom of kidney cancer is blood in the urine. The diagnosis of kidney cancer is supported by findings of the medical history and examination, blood, urine, and x-ray tests, and confirmed with a biopsy. Kidney cancer is treated with surgery, embolization, radiation therapy, hormone therapy, biological therapy, or chemotherapy.

Cancer, larynx: Cancer of the voice box. The larynx is the voice box located at the top of the windpipe (trachea). Cancer of the larynx occurs most often in people over the age of 55 years. People who stop smoking can greatly reduce their risk of cancer of the larynx. Painless hoarseness can be a symptom of cancer of the larynx. The larynx can be examined with a viewing tube called a laryngoscope. Cancer of the larynx is usually treated with radiation therapy or surgery. Chemotherapy can also be used for cancers that have spread.

Cancer, leukemia: Leukemia is a cancer of the white blood cells. Leukemias are grouped by how quickly the disease develops (acute or chronic) as well as by the type of blood cell that is affected. People with leukemia are at significantly increased risk for developing infections, anemia, and bleeding. Diagnosis of leukemia is supported by findings of the medical history and examination, and examining blood under a microscope. Leukemia cells can be detected and further classified with a bone marrow aspiration and/or biopsy. Most patients with leukemia are treated with chemotherapy. Some patients also may have radiation therapy and/or bone marrow transplantation.

Cancer, lung: Cancer of the major organ of respiration—the lung. Lung cancer kills more men and women than any other form of cancer. Since the majority of lung cancer is diagnosed at a relatively late stage, only 10% of all lung cancer patients are ultimately cured. Eight out of 10 lung cancers are due to tobacco smoke. Lung cancers are classified as either small cell or non-small cell cancers. Persistent cough and bloody sputum can be symptoms of lung cancer. Lung cancer can be diagnosed based on examination of sputum, or tissue examination with biopsy using bronchoscopy, needle through the chest wall, or surgical excision.

Cancer, lymphoma, Hodgkin’s (adult): A type of lymphoma (cancer of the lymphatic system). The most common symptom of Hodgkin’s disease is a painless swelling in the lymph nodes in the neck, underarm, or groin. Hodgkin’s disease is diagnosed when abnormal tissue is detected by a pathologist after a biopsy of an enlarged lymph node. Treatment usually includes radiation therapy or chemotherapy. Regular follow-up examinations are important after treatment for Hodgkin’s disease. Patients treated for Hodgkin’s disease have an increased risk of developing other types of cancer later in life, especially leukemia.

Cancer, lymphoma, non-Hodgkin’s: A lymphoma is a cancer that develops in the lymphatic system. The most common symptom of non-Hodgkin’s lymphomas is a painless swelling in the lymph nodes in the neck, underarm, or groin. Non-Hodgkin’s lymphomas are diagnosed with a biopsy of an enlarged lymph node. Follow-up examinations are important after lymphoma treatment. Most relapses occur in the first 2 years after therapy.

Cancer, malignant melanoma: A skin cancer that begins in cells called melanocytes that can grow together to form benign (not cancerous) moles. A change in size, shape, or color of a mole can be a sign of melanoma. Melanoma can be cured if detected early, before spread (metastasis) to other areas of the body. Diagnosis is confirmed with a biopsy of the abnormal skin. Sun exposure can cause skin damage that can lead to melanoma.

Cancer, melanoma: A skin cancer that begins in cells called melanocytes that can grow together to form benign (not cancerous) moles. A change in size, shape, or color of a mole can be a sign of melanoma. It can be cured if detected early, before spread (metastasis) to other areas. Diagnosis is confirmed by a biopsy of the abnormal skin. Sun exposure can cause skin damage that can lead to melanoma.

Cancer, myeloma: A bone marrow cancer involving a type of white blood cell called a plasma (or myeloma) cell. The tumor cells can form a single collection (a plasmacytoma) or many tumors (multiple myeloma). Plasma cells are part of the immune system and make antibodies. Because patients have an excess of identical plasma cells, they have too much of one type of antibody. As myeloma cells increase in number, they damage and weaken the bones, causing pain and often fractures. When bones are damaged, calcium is released into the blood leading to hypercalcemia (too much calcium in the blood) and that causes loss of appetite, nausea, thirst, fatigue, muscle weakness, restlessness, and confusion. Myeloma cells prevent the bone marrow from forming normal plasma cells and other white blood cells important to the immune system so patients may not be able to fight infections. The cancer cells can also prevent the growth of new red blood cells, causing anemia. Excess antibody proteins and calcium may prevent the kidneys from filtering and cleaning the blood properly.

Cancer, multiple myeloma: A bone marrow cancer involving a type of white blood cell called a plasma (or myeloma) cell. The tumor cells can form a single collection (a plasmacytoma) or many tumors (multiple myeloma). Plasma cells are part of the immune system and make antibodies. Because patients have an excess of identical plasma cells, they have too much of one type of antibody. As myeloma cells increase in number, they damage and weaken the bones, causing pain and often fractures. When bones are damaged, calcium is released into the blood leading to hypercalcemia (excess calcium in the blood) and that causes loss of appetite, nausea, thirst, fatigue, muscle weakness, restlessness, and confusion. Myeloma cells prevent the bone marrow from forming normal plasma cells and other white blood cells important to the immune system so patients may not be able to fight infections. The cancer cells can also prevent the growth of new red blood cells, causing anemia. Excess antibody proteins and calcium may prevent the kidneys from filtering and cleaning the blood properly Cancer, non-Hodgkin’s lymphoma: A lymphoma is a cancer that develops in the lymphatic system. The most common symptom of non-Hodgkin’s lymphomas is a painless swelling in the lymph nodes in the neck, underarm, or groin. Non-Hodgkin’s lymphomas are diagnosed with a biopsy of an enlarged lymph node. Follow-up examinations are important after lymphoma treatment. Most relapses occur in the first 2 years after therapy.

Cancer, oral: Cancer of the mouth area. A sore in the mouth that does not heal can be a warning sign of oral cancer. A biopsy is the only to know whether as abnormal area in the oral cavity is cancer. Oral cancer is caused by tobacco (smoking and chewing) and alcohol use. Surgery to remove the tumor in the mouth is the usual treatment for patients with oral cancer.

Cancer, ovarian: Cancer of the egg sac of females (ovary). In women under age 30, most ovarian growths are benign, fluid-filled sacs called cysts. There are several types of ovarian cancer. Symptoms of ovarian cancer can be vague. Detection of ovarian cancer involves physical examination (including pelvic exam), ultrasound, x-ray tests, CA-125 blood test and biopsy of the ovary.

Cancer, ovary: Cancer of the egg sac of females. Most ovarian growths in women under age 30 are benign, fluid-filled cysts. There are several types of ovarian cancer. Symptoms of ovarian cancer can be vague. Detection of ovarian cancer involves physical examination (including pelvic exam), ultrasound, x-ray tests, CA-125 blood test and biopsy of the ovary.

Cancer, pancreas: Cancer of the organ which produces many juices that are important for digesting food as well as hormones, such as insulin and glucagon. Pancreatic cancer has been called a "silent" disease because early pancreatic cancer usually does not cause symptoms. If the tumor blocks the common bile duct and bile cannot pass into the digestive system, the skin and whites of the eyes may become yellow, and the urine darker as a result of accumulated bile pigment called bilirubin. This condition is referred to as jaundice.

Cancer, pancreatic: Cancer of the organ which produces many juices that are important for digesting food as well as hormones, such as insulin and glucagon. Pancreatic cancer has been called a "silent" disease because early pancreatic cancer usually does not cause symptoms. If the tumor blocks the common bile duct and bile cannot pass into the digestive system, the skin and whites of the eyes may become yellow, and the urine darker as a result of accumulated bile pigment called bilirubin. This condition is referred to as jaundice.

Cancer, prostate: Cancer of the gland that produces some of the components of semen fluid. Prostate cancer is the second leading cause of death of males in the U.S. Prostate cancer is often first detected as a hard nodule during a routine rectal examination. The PSA blood test is a screening test for prostate cancer. Diagnosis of prostate cancer is established when cancer cells are identified in prostate tissue obtained by a biopsy. In some patients, prostate cancer is life threatening. In many others, prostate cancer can exist for years without causing any health problems. Treatment options for prostate cancer include observation, radiation therapy, surgery, hormonal therapy, and chemotherapy.

Cancer, prostatic: Cancer of the gland (prostate) that produces some of the components of semen fluid. The second leading cause of death of males in the U.S. Prostate cancer is often first detected as a hard nodule during a routine rectal examination. The PSA blood test is a screening test for prostate cancer. Diagnosis of prostate cancer is established when cancer cells are identified in prostate tissue obtained by a biopsy. In some patients, prostate cancer is life threatening. In many others, prostate cancer can exist for years without causing any health problems. Treatment options for prostate cancer include observation, radiation therapy, surgery, hormonal therapy, and chemotherapy.

Cancer, rectal: A malignant tumor arising from the inner wall of the end (rectum) of the large intestine. The third leading cause of cancer in males, fourth in females in the U.S. Risk factors for cancer of the colon and rectum (colorectal cancer) include heredity, colon polyps, and long standing ulcerative colitis. Most colorectal cancers develop from polyps. Removal of colon polyps can prevent colorectal cancer. Colon polyps and early cancer can have no symptoms. Therefore, regular screening is important. Diagnosis can be made by barium enema or by colonoscopy with biopsy confirmation of cancer tissue. Surgery is the most common treatment for colorectal cancer.

Cancer, skin: Cancer of the outer surface of the body. The most common cancer in the U.S. There are many types of skin cancer. Ultraviolet light from sunlight is the main cause of skin cancer. Unexplained changes in the appearance of the skin, lasting longer than 2 weeks, should be evaluated by a doctor. The cure rate for skin cancer could be 100% if all skin cancers were brought to a doctor’s attention before they had a chance to spread.

Cancer, stomach: Cancer of the major organ that holds food for digestion. Stomach cancer (gastric cancer) can develop in any part of the stomach and spread to other organs. Stomach ulcers do not appear to increase a person’s risk of developing stomach cancer. Symptoms of stomach cancer are often vague, such as loss of appetite or weight. The cancer is diagnosed with a biopsy of stomach tissue during a procedure called an endoscopy.

Cancer symptoms: Abnormal sensations or conditions that persons can notice that are a result of a cancer. It is important to see your doctor for regular checkups and not wait for problems to occur. But you should also know that the following symptoms may be associated with cancer: changes in bowel or bladder habits, a sore that does not heal, unusual bleeding or discharge, thickening or lump in the breast or any other part of the body, indigestion or difficulty swallowing, obvious change in a wart or mole, or nagging cough or hoarseness. These symptoms are not always a sign of cancer. They can also be caused by less serious conditions. Only a doctor can make a diagnosis. It is important to see a doctor if you have any of these symptoms. Don’t wait to feel pain. Early cancer often does not cause pain.

Cancer, testicles: Cancer of the male sex organ (testicle) that normally produces the hormone testosterone. One of the most common cancers in young men. Most testicular cancers are found by men themselves as a lump in the testicle. The risk of cancer of the testicles is increased in males whose testicles did not move down normally into the scrotum (holding sac for the testicles) during development if the problem is not corrected in early childhood. This condition is referred to as undescended testicles. When a growth in the testicle is detected, cancer is confirmed after surgical removal of the affected testicle (orchiectomy) and examination of the tissue under a microscope. Testicular cancer is almost always curable if it is found early.

Cancer, testicular: Cancer of the male sex organ (testicle) that normally produces the hormone testosterone. One of the most common cancers in young men. Most testicular cancers are found by men themselves as a lump in the testicle. The risk of cancer of the testicles is increased in males whose testicles did not move down normally into the scrotum (holding sac for the testicles) during development if the problem is not corrected in early childhood. This condition is referred to as undescended testicles. When a growth in the testicle is detected, cancer is confirmed after surgical removal of the affected testicle (orchiectomy) and examination of the tissue under a microscope. Testicular cancer is almost always curable if it is found early.

Cancer, thyroid: Cancer of the gland in front of the neck that normally produces thyroid hormone which is important to the normal regulation of the metabolism of the body. There are four major types of cancer of the thyroid gland. Persons who received radiation to the head or neck in childhood should be examined by a doctor every 1 to 2 years. The most common symptom of thyroid cancer is a lump, or nodule, that can be felt in the neck. The only certain way to tell whether a thyroid lump is cancer is by examining the thyroid tissue obtained using a needle or surgery for biopsy.

Cancer, uterine: Cancer of the womb (uterus). Cancer of the uterus occurs most often in women between the ages of 55 and 70 years. Abnormal bleeding after menopause is the most common symptom of cancer of the uterus. Cancer of the uterus is diagnosed based on the results of the pelvic examination, pap smear, biopsy of the uterus, and D and C procedure.

Cancer, uterus: Cancer of the womb. Also referred to as uterine cancer. Cancer of the uterus occurs most often in women between the ages of 55 and 70 years. Abnormal bleeding after menopause is the most common symptom of cancer of the uterus. Cancer of the uterus is diagnosed based on the results of the pelvic examination, pap smear, biopsy of the uterus, and D and C procedure.

Canker sores: Also known as aphthous ulcers, these are small ulcer craters in the lining of the mouth that are frequently painful and sensitive. Canker sores are one of the most common problems that occur in the mouth. About 20% of the population (1 out of 5) people will have canker sores at any one time. Canker sores typically last for 10-14 days and heal without scarring The word canker comes from the Latin cancer for crab. (The Latin cancer was once pronounced kanker from which came canker). Chronic ulcers might seem as hard as a crab shell.

Capillaries: Capillaries are tiny blood vessels that distribute blood from arteries to the tissues of the body. They are part of the circulatory system. When pink areas of skin are compressed this causes blanching. This occurs because blood is pressed out of the capillaries. (see blood).

Carbuncles: A skin abscess, a collection of pus that forms inside the body. Antibiotics are often not very helpful in treating abscesses. The main treatments include hot packs and draining ("lancing") the abscess, but only when it is soft and ready to drain. If you have a fever or long-term illness, such as cancer or diabetes, or are taking medications that suppress the immune system, you should contact your healthcare practitioner if you develop an abscess.

Carcinogen: A substance or agent that is known to cause cancer.

Carcinoma: Cancer that begins in the tissues lining or covering an organ.

Carcinoma in situ: Cancer that involves only the cells in which it began and that has not spread to other tissues.

Cardiac: Having to do with the heart.

Cardiac muscle: A type of muscle with unique features and only found in the heart.

Cardiopulmonary: Having to do with both the heart and lungs.

Cardiopulmonary bypass: Bypass of the heart and lungs as, for example, in open heart surgery. Blood returning to the heart is diverted through a heart-lung machine (a pump-oxygenator) before returning it to the arterial circulation. The machine does the work both of the heart (pump blood) and the lungs (supply oxygen to red blood cells).

Cardiopulmonary resusitation (CPR): CPR involves breathing for the victim and applying external chest compression to make the heart pump. In the case of an early heart attack, death can often be avoided if a bystander starts CPR promptly (within 5 minutes of the onset of ventricular fibrillation). When paramedics arrive, medications and/or electrical shock (cardioversion) to the heart can be administered to convert ventricular fibrillation to a normal heart rhythm. Therefore, prompt CPR and rapid paramedic respronse can improve the survival chances from a heart attack.

Carditis: Inflammation of the heart.

Care proxy, health: A health care proxy is one form of advance medical directive. Advance medical directives preserve the person’s right to accept or reject a course of medical treatment even after that person becomes mentally or physically incapacitated to the point of being unable to communicate those wishes. There are two basic forms of advance directives:

(1) a living will, in which the person outlines specific treatment guidelines that are to be followed by health care providers; (2) a health care proxy (also called a power of attorney for health-care decision-making) in which the person designates a trusted individual to make medical decisions in the event that he or she becomes too incapacitated to make such decisions. Advance directive requirements vary greatly from one jurisdiction to another and should therefore be drawn up in consultation with an attorney who is familiar with the laws of the particular jurisdiction. (This entry is based upon material from the National MS Society).
Caries: Dental cavities. Holes in the two outer layers of a tooth called the enamel and the dentin. The enamel is the outermost white hard surface and the dentin is the yellow layer just beneath enamel. Both layers serve to protect the inner living tooth tissue called the pulp, where blood vessels and nerves reside. Small cavities may not cause pain, and may be unnoticed by the patient. Larger cavities can collect food, and the inner pulp of the affected tooth can become irritated by bacterial toxins, foods that are cold, hot, sour, or sweet—causing toothache.
Carotene, beta: An antioxidant which protects cells against oxidation damage that can lead to cancer. Beta carotene is converted, as needed, to vitamin A. Food sources of beta carotene include vegetables such as carrots, sweet potatoes, spinach and other leafy green vegetables; and fruit such as cantaloupes and apricots. Excessive carotene in the diet can temporarily yellow the skin, a condition called carotenemia, commonly seen in infants fed largely mushed carrots.

Carotenemia: Tempoary yellowing of the skin due to excessive carotene in the diet, commonly seen in infants fed too much mushed carrots or adults consuming high quantities of carrots or beta carotene.

Carpal tunnel syndrome: Condition caused by irritation of the median nerve at the wrist. Predisposing factors include obesity, pregnancy, hypothyroidism, arthritis, diabetes, and trauma. Tendon inflammation from repetitive work such as prolonged typing is another cause. Symptoms include numbness and tingling of the hand. Diagnosis is suspected based on symptoms, supported by physical examination signs, and confirmed by nerve conduction testing. Treatment of depends on the severity of symptoms and the underlying cause.

Carrier test: A test designed to detect carriers of a gene for recessive genetic disorder. For example, carrier testing is done for sickle cell trait, thalassemia trait, and the Tay-Sachs gene.

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

Cataract: A clouding or loss of transparency of the eye lens. There are many causes of cataracts including aging, diabetes, cortisone medication, trauma, or other diseases. Cataracts will affect most people if they live long enough. Symptoms include double or blurred vision and sensitivity to light and glare. Cataracts can be diagnosed when the doctor examines the eyes with a viewing instrument. The ideal treatment for cataracts is surgical implantation of a new lens. Sunglasses can help to prevent cataracts.

Catheter: A thin, flexible tube. When a catheter is placed in a vein, it provides a pathway for giving drugs, nutrients, fluids, or blood products. Also, blood samples can be withdrawn through the catheter.

CAT scan: Computerized axial tomography (CAT) scanning adds X-ray images with the aid of a computer to generate cross-sectional views anatomy. It can identify normal and abnormal structures and be used to guide procedures. CAT scanning is painless. Iodine-containing contrast material is sometimes used in CAT scanning. If you having a CAT scan and are allergic to iodine or contrast materials, you should notify your physicians and radiology staff.

Cauliflower-ear deformity: Destruction of the underlying cartilage framework of the outer ear (pinnae), usually caused by either infection or trauma, resulting in a thickening of the ear. Classically, blood collects (hematoma) between the ear cartilage and the skin. There is a marked thickening of the entire ear which may be so extensive that the shape of the ear becomes unrecognizable. The ear is said to look like a piece of cauliflower. It is typically seen in wrestlers and boxers who have had repeated trauma to the ear.

Causes of cancer: Cancer is a group of more than 100 different diseases. Benign tumors are not cancer; malignant tumors are cancer. Most cancers are named for the type of cell or the organ in which they begin. When cancer spreads (metastasizes), the new tumor has the same name as the original (primary) tumor. Skin cancer is the most common type of cancer for both men and women. The second most common cancer in men is prostate cancer, in women it is breast cancer. Lung cancer is the leading cause of death from cancer for both men and women in the U.S. Cancer is NOT contagious.

Cauterization: The use of heat to destroy abnormal cells. Also called diathermy or electrodiathermy.

Cavities: Holes in the two outer layers of a tooth called the enamel and the dentin. The enamel is the outermost white hard surface and the dentin is the yellow layer just beneath enamel. Both layers serve to protect the inner living tooth tissue called the pulp, where blood vessels and nerves reside. Small cavities may not cause pain, and may be unnoticed by the patient. Larger cavities can collect food, and the inner pulp of the affected tooth can become irritated by bacterial toxins, foods that are cold, hot, sour, or sweet—causing toothache. Also referred to as caries.

Cavity, abdominal: The space between the abdominal wall and the spine.

CCD (Central core disease of muscle): One of the conditions that produces ‘floppy baby’ syndrome. CCD causes hypotonia (floppiness) in the newborn baby, slowly progressive muscle weakness, and muscle cramps after exercise. Muscle biopsy shows a key diagnostic finding (absent mitochondria in the center of many type I muscle fibers). CCD is inherited as a dominant trait. The CCD gene is on chromosome 19 (and involves ryanodine receptor-1).

CD4 count, absolute: The number of "helper" T-lymphocytes in a cubic millimeter of blood. With HIV, the absolute CD4 count declines as the infection progresses. The absolute CD4 count is frequently used to monitor the extent of immune suppression in persons with HIV. Also called a T4 count.

cDNA: Complementary DNA. cDNA is made from a messenger RNA template. The single- stranded form is often used as a probe in physical mapping.

CEA assay: A laboratory test to measure the level of carcinoembryonic antigen (CEA), a substance that is sometimes found in an increased amount in the blood of colorectal cancer patients.

Cecum: The first portion of the large bowel which receives fecal material from the small bowel (ileum). The appendix is also attached to the cecum. The cecum is located in the lower right quadrant of the abdomen.

Celiac disease, adult: See Celiac sprue.

Celiac sprue: A result of an immune reaction to gluten, a protein found in wheat or related grains and present in many foods that we eat. Celiac sprue causes impaired absorption and digestion of nutrients through the small intestine. Symptoms include requent diarrhea and weight loss. A skin condition called dermatitis herpetiformis can be associated with celiac sprue. The most accurate test for celiac sprue is a biopsy of the involved small bowel. Treatment is to avoid gluten in the diet. Medications are used for refractory (stubborn) sprue.

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

Cell cloning: The process of producing a group of cells (clones), all genetically identical, from a single ancestral cell.

Cells, reproductive: The eggs and sperm are the reproductive cells. Each mature reproductive cell is haploid in that it has a single set of 23 chromosomes.

Centimorgan (cM): A unit of measure of genetic recombination frequency. One cM is equal to a 1% chance that a marker at one genetic locus will be separated from a marker at another locus due to crossing over in a single generation. In humans, 1 cM is equivalent, on average, to 1 million base pairs. The centimorgan is named after the pioneering (and Nobel Prize winning) geneticist Thomas Hunt Morgan.

Central core disease of muscle (CCD): One of the conditions that produces ‘floppy baby’ syndrome. CCD causes hypotonia (floppiness) in the newborn baby, slowly progressive muscle weakness, and muscle cramps after exercise. Muscle biopsy shows a key diagnostic finding (absent mitochondria in the center of many type I muscle fibers). CCD is inherited as a dominant trait. The CCD gene is on chromosome 19 (and involves ryanodine receptor-1).

Central nervous system: The central nervous system is that part of the nervous system consisting of the brain and spinal cord.

Centromere: The "waist" of the chromosome essential for the division and the retention of the chromosome in the cell. The centromere is a uniquely specialized region of the chromosome to which spindle fibers attach during cell division.

CEPH: The Centre d’Etudes du Polymorphisme Humain (CEPH), an internationally reknowned research laboratory created in Paris in 1984 by Professor Jean Dausset (Nobel Prize, Medicine and Physiology, 1980) to provide the scientific community with resources for human genome mapping. Also known as the Fondation Jean Dausset-CEPH.

Cephalgia: Headache. (One of those things we all know but that defies an easy definition.) Literally, headache is an ache in the head. It is pain in the head. The Greek "algos" means "pain."

Cerebellum: The portion of the brain in the back of the head between the cerebrum and the brain stem.

Cerebral hemispheres: The two halves of the cerebrum, the largest part of the brain.

Cerebritis: Inflammation of the brain.

Cerebrospinal fluid: The watery fluid that fills the spaces in and around the brain and spinal cord. Also called CSF.

Cerebrovascular accident (CVA): A stroke. The sudden death of brain cells due to lack of oxygen caused by blockage of blood flow or rupture of an artery to the brain. Sudden weakness or paralysis of one side of the body can be a symptom of a stroke. A suspected stroke can be confirmed by scanning the brain with special X-ray tests, such as CAT scanning. Stroke prevention involves minimizing risk factors, such as controlling high blood pressure and diabetes.

Cerebrovascular accident (CVA) prevention: In many cases, a person may have a transient ischemic attack (TIA). a neurological event with the symptoms of a stroke, but the symptoms go away within a short period of time. This is often caused by the narrowing or ulceration of the carotid arteries (the major arteries in the neck that supply blood to the brain). If not treated, there is a high risk of having a major stroke in the future. If you suspect a TIA, you should seek medical attention right away. An operation to clean out the carotid artery and restore normal blood flow through the artery (a carotid endarterectomy) markedly reduces the incidence of a subsequent stroke. In other cases, when a person has a narrowed carotid artery, but no symptoms, the risk of having a stroke can be reduced with medications such as aspirin and ticlopidine (TICLID). These medications act by partially blocking the function of blood elements, called platelets, which assist blood clotting.

Cerebrum: The largest part of the brain. It is divided into two hemipheres, or halves.

Cervical cancer: Cancer of the entrance to the womb (uterus). Regular pelvic exams and Pap testing can detect precancerous changes in the cervix. Precancerous changes in the cervix may be treated with cryosurgery, cauterization, or laser surgery. The most common symptom of cancer of the cervix is abnormal bleeding. Cancer of the cervix can be diagnosed using a Pap test or other procedures that sample the cervix tissue. Cancer of the cervix requires different treatment than cancer that begin in other parts of the uterus.

Cervical intraepithelial neoplasia: A general term for the growth of abnormal cells on the surface of the cervix. Numbers from 1 to 3 may be used to describe how much of the cervix contains abnormal cells. Also called CIN.

Cervical rib: A rib which arises from the seventh cervical vertebrae (above the normal first rib). Occurs in only about 0.5% of people. May cause nerve and artery problems.

Cervicitis: Inflammation of the cervix.

Cervix: The cervix, is the end of the womb, or uterus that protrudes into the upper vagina.

Cesarian section: The obstetrical procedure is often spelled this way in the U.S. with just an "e"although the Roman emperor remains Caesar in America with an "ae". Procedure in which an infant, rather than being born vaginally, is surgically removed from the uterus. Also referred to as a C section. As the name "Caesarian" suggests, this is not exactly a new procedure. It was done in ancient civilizations upon the death of a near-full-term pregnant woman to salvage the baby. Julius Caesar (or one of his predecessors) was born by this procedure. Hence, the name "Caesarian". The term "section" in surgery refers to the division of tissue. What is being divided here is the abdominal wall of the mother as well as the wall of the uterus in order to extract the baby. In Shakespeare’s "Macbeth" the Witches’ prophecy was that "...none of woman born/ Shall harm Macbeth" (IV.i). Unfortunately for Macbeth, the Scottish nobleman Macduff was "from his mother’s womb/ Untimely ripped." and thus not naturally "born of woman"(V.vii). Macduff was the only agent capable of destroying Macbeth. He killed Macbeth in battle. See: Caesarian section.

Charbon: Known also as anthrax, charbon is a serious bacterial infection. It is not primarily a human disease but rather an infection of animals. Cattle, sheep, horses, mules, and some wild animals are highly susceptible. Humans (and swine) are generally resistant to anthrax. Anthrax can take different forms. With the lung form of the disease. People inhale the anthrax spores and, if untreated, are likely to die. An intestinal form is caused by eating meat contaminated with anthrax. But most human anthrax comes from skin contact with animal products. Cutaneous (skin) anthrax was once well known among people who handled infected animals, like farmers, woolsorters, tanners, brushmakers and carpetmakers in the days when the brushes and carpets were animal products. The hallmark of skin anthrax is a carbuncle, a cluster of boils, that ulcerates in an ugly way. Typically this lesion has a hard black center surrounded by bright red inflammation. This accounts for its name, "anthrax", the Greek word for "coal". "Charbon" in French means "coal."

Chalazion: Also called a Meibomian cyst or a tarsal cyst, a chalazion is an inflammation of the oil gland of the eyelid.

Chancre: The classic non-painful ulcer of syphilis. The chancre forms in the first (primary) stage of syphilis, is highly contagious and can last 1-5 weeks. The disease can be transmitted from any contact with one of the ulcers, which are teeming with spirochetes. If the ulcer is outside of the vagina or on the scrotum of the male, the use of condoms may not help in preventing transmission of the disease. Likewise, if the ulcer is in the mouth, merely kissing the infected individual can spread syphilis. (The word chancre is the French for a little ulcer. Chancre and the English canker come from the Latin cancer for crab. Why? Perhaps because chronic ulcers can be hard like the shell of a crab).

Chemoprevention: The use of natural or laboratory-made substances to prevent cancer.

Chemotherapy: Treatment with anticancer drugs.

Chest film: Most common X-ray used to detect abnormalities in or within the thoracic cage, such as the lungs, heart, aorta, and the bones of the chest. Extra metallic objects, such as jewelry are removed from the chest and neck areas for a chest x-ray to avoid interference with x-ray penetration and improve accuracy of the interpretation.

Chest pain: There are many causes of chest pain. One is angina which results from inadequate oxygen supply to the heart muscle. Angina can be caused by coronary artery disease or spasm of the coronary arteries. Chest pain can also be due to a heart attack (coronary occlusion) and other important diseases. Do not try to ignore chest pain and "work (or play) though it." Chest pain is a warning to seek medical attention.

Chest X-ray: Commonly used to detect abnormalities in the lungs, but can also detect abnormalities in the heart, aorta, and the bones of the thoracic area. Metallic objects, such as jewelry are removed from the chest and neck areas for a chest x-ray to avoid interference with x-ray penetration and improve accuracy of the interpretation.

Chickenpox: A highly infectious viral disease, chickenpox is known medically (and in many countries) as varicella. Chickenpox has nothing to do with chicken. The name was meant to distinguish this "weak" form of the pox from smallpox (chicken being used, as in chickenhearted, to mean weak or timid). The "pox" of chickenpox is no major matter unless infected (through scratching) or occur in an immunodeficient person. However, there can be very major problems with chickenpox including pneumonia and encephalitis, particularly in adults but also sometimes in children, and reactivation of the same herpes virus is reponsible for shingles (zoster). The current aim in the U.S. is to achieve universal (or nearly universal) immunization of children with the chickenpox vaccine.

Chickenpox immunization: This vaccine prevents the common disease known as chickenpox (varicella zoster). While chickenpox is often considered a trivial illness, it can cause significant lost time on the job and in school and have serious complications including ear infections, pneumonia, and infection of the rash with bacteria, inflammation of the brain (encephalitis) leading to difficulty with balance and coordination (cerebellar ataxia), damaged nerves (palsies), and Reye’s syndrome, a potentially fatal complication. The vaccination requires only one shot given at about a year of age. If an older person has not had chickenpox, the shot may be given at any time. There have been few significant reactions to the chickenpox vaccine. All children, except those with a compromised immune system, should have the vaccination.

Chilblains: A form of cold injuries along with"trench foot," and frostbite. Cold injuries occur with and without freezing of body tissues. The young and the elderly are especially prone to cold injury. Alcohol increases the risk of cold injury which can lead to loss of body parts and even to death. It is important not to thaw an extremity if there is a risk of it re-freezing.

Children’s immunizations: In the United States, it is recommended that all children receive vaccination against:

Hepatitis B
Diphtheria, tetanus, pertussis
Haemophilus influenzae type B (HIB)
Poliovirus
Measles, mumps, rubella
Varicella zoster virus (chickenpox).
Every child in the U.S. should have these vaccinations except when there are special circumstances and the child’s doctor advises specifically against a vaccination.
Chiropractic: A system of diagnosis and healing based on the concept that health and disease are related to nervous system function, disease is due to malfunction of the nervous system due to noxious irritants, and health can be restored by their removal.

Chiropractor: Someone who practices chiropractic.

Chlamydia: A bacteria that causes infection very similar to gonorrhea in the way that it is spread and the symptoms it produces. Like gonorrhea, it is found in the cervix and urethra and can live in the throat or rectum. It is very destructive to the tubes (fallopian tubes) that transport eggs from a woman’s ovary to the womb and can cause infertility and tubal pregnancy and severe pelvic infection. Because it is common for infected women to have no symptoms, it is often untreated, leading to extensive destruction of the fallopian tubes and fertility problems. Like gonorrhea, chlamydia is associated with an increased incidence of preterm births. The infant can also acquire the disease during passage through the birth canal, leading to eye involvement or pneumonia. For this reason, all newborns are treated with eye drops after birth. The drops contain an antibiotic which treats chlamydia. Treatment of all newborns is routine because of the large number of infected women without symptoms, and the dire consequences of chlamydial eye infection to the newborn.

Cholecystitis: Inflammation of the gallbladder, a complication of gallstones which are formed by cholesterol and pigment (bilirubin) in bile. (Bile is produced in the liver and stored in the gallbladder). Cholecystitis is frequently associated with infection in the gallbladder. Risk factors for cholesterol gallstones include age, obesity, female gender, multiple pregnancies, birth control pills, and heredity. The most common symptom is pain in the upper abdomen. Diagnosis is usually made with ultrasound of the abdomen. Some patients have no symptoms. Patients with mild and infrequent symptoms may consider oral medication to dissolve gallstones. Surgery (standard or laparoscopic) is considered for patients with severe symptoms and for patient with cholecystitis.

Cholesterol: The most common steroid in the body, cholesterol is produced in the liver and carried in the bloodstream by lipoproteins. LDL (Low-Density Lipoprotein) cholesterol (the "bad" cholesterol) is associated with an increased risk of coronary artery (heart) disease. After age 20 years, cholesterol level testing is recommended every 5 years. Diets high in cholesterol and saturated fats can increase blood cholesterol levels. Diets high in unsaturated fats can lower blood cholesterol. The most effective means of lowering blood cholesterol is to reduce dietary saturated fat intake. Treatment of elevated cholesterol includes diet, weight loss, regular exercise, and occasionally medications.

Chondroplasia: The formation of cartilage by specialized cells called chondrocytes.

Chondrosarcoma: A cancer that forms in cartilage.

Chordae tendineae: Thread-like bands of fibrous tissue which attach on one end to the edges of the tricuspid and mitral valves and on the other to the papillary muscles.

Chordoma: A form of bone cancer that usually starts in the lower spinal column.

Chorion: The outermost of the two fetal membranes—the amnion is the innermost --. which together surround the embryo. The chorion develops villi (vascular fingers) and gives rise to the placenta. In Greek, the word "chorion" means "skin or leather."

Chorionic villus sampling (CVS): Procedure used at 8-10 weeks of pregnancy for prenatal diagnosis (diagnosis of conditions of the fetus before birth). Tissue is withdrawn from an area of the placenta, namely the villi of the chorion.

Chromatids: The daughter strands of a duplicated chromosome joined together by a centromere.

Chromosomes: Chromosomes are microscopic components of every cell in the body that carry all of the genetic material that will eventually determine hair color, eye color and our overall appearance and makeup.

Chromosome complement: The whole set of chromosomes for the species. In humans, the chromosome complement (which is also called the karyotype) consists of 46 chromosomes.

Chromosome disorder: An abnormal condition due to an abnormality of the chromosomes. For example, Down syndrome (the genetic abnormality featuring three chromosome 21s, instead of two, also refered to as trisomy 21) is a chromosome disorder.

Chromosome map: The chart of the linear array of genes on a chromosome. The Human Genome Project aims to map all of the human chromosomes.

Chromosomes in multiple miscarriages: Couples who have had more than one miscarriage (spontaneous abortion) have about a 5% chance that one member of the couple is carrying a chromsome translocation responsible for the miscarriages.

Chronic: This is an important term in medicine. It comes from the Greek chronos meaning time (as in chronometer). It means lasting a long time. A chronic condition is one lasting 3 months or more, by the definition of the U.S. National Center for Health Statistics. In ancient Greece, the "father of medicine" Hippocrates distinguished diseases that were acute (abrupt, sharp and brief) from those that were chronic. This is still a very useful distinction. Subacute has been coined to designate the mid-ground between acute and chronic.

Chronic arthritis, systemic-onset juvenile (Still’s disease): Also known as systemic-onset juvenile rheumatoid arthritis, this is a form of joint disease (arthritis) that presents with systemic (bodywide) symptoms including a high intermittent fever, a transient salmon-colored skin rash, swollen lymph glands, enlargement of the liver and spleen, and inflammation of the lungs (pleuritis) and around the heart (pericarditis) The arthritis may not be apparent at first but it always surfaces and may persists long after the systemic symptoms are gone.

Chronic fatigue syndrome (CFS): A debilitating medical condition, chronic in nature, cause unknown, diagnosis by exclusion, no known verified test, treatment by relief of symptoms, life style changes, and occasionally time. Known also as Chronic Fatigue and Immune Dysfunction Syndrome (CFIDS) and as Myalgic Encephalomyelitis (ME), there has been some debate over the existence and causes of this condition.

Chronic leukemia: Cancer of the blood cells (leukemia) that progresses slowly.

Chronic phase: Refers to the early stages of chronic myelogenous leukemia. The number of immature, abnormal white blood cells in the bone marrow and blood is higher than normal, but lower than in the accelerated or blast phase.

Chronicity: Characterized by long duration. The state of being chronic.

Circulation: The movement of fluid in a regular or circuitous course. Although the noun "circulation" does not necessarily refer to the circulation of the blood, for all practical purposes today it does. Heart failure is an example of a problem with the circulation.

Circulation, fetal: The blood circulation in the fetus (the unborn baby). Before birth, the blood from the heart that is destined (in the pulmonary artery) for the lungs is shunted away from the lungs and returned to the greatest of arteries (the aorta). The shunt is through a short vessel called the ductus arteriosus. When this shunt is open, it is said to be a patent (pronounced pá tent) ductus arteriosus (PDA). The PDA usually closes at or shortly after birth and blood is permitted to course freely to the lungs.

Circulatory: Having to do with the circulation, the movement of fluid in a regular or circuitous course. Although the adjective "circulatory" need not necessarily refer to the circulation of the blood, for all practical purposes today it does. A circulatory problem is taken usually to be a problem with the blood circulation, for example with heart failure.

Circulatory System: The circulatory system is a composed of the heart, arteries, capillaries and veins. It serves to transport blood low in oxygen from the body to the lungs and heart (veins) and oxygenated blood from the lungs and heart throughout the body (arteries). (see heart, blood).

Cirrhosis: An abnormal liver condition characterized by irreversible scarring of the liver. Alcohol and viral hepatitis B and C are among the many causes of cirrhosis. Cirrhosis can cause yellowing of the skin (jaundice), itching, and fatigue. Diagnosis of cirrhosis can be suggested by physical examination and blood tests, and can be confirmed by liver biopsy in some patients. Complications of cirrhosis include mental confusion, coma, fluid accumulation (ascites), internal bleeding, and kidney failure. Treatment of cirrhosis is designed to limit any further damage to the liver as well as complications. Liver transplantation is becoming an important option for patients with advanced cirrhosis.

Cl: The chemical symbol for chloride. Sodium chloride (ordinary salt) is chemically represented NaCl.

Clap: Gonorrhea, a bacterial infection transmitted by sexual contact. Gonorrhea is one of the oldest known sexually transmitted diseases (STDs). In women infected with this bacteria (Neisseria gonorrhoeae), 25-40% will also be infected with another bacteria that can cause another STD called chlamydia. Gonorrhea is NOT transmitted from toilet seats. More than half of women infected with gonorrhea do not have any symptoms. If symptoms occur, they may include burning or frequent urination, yellowish vaginal discharge, redness and swelling of the genitals, and a burning or itching of the vaginal area. Untreated, gonorrhea can lead to severe pelvic infections.

Clavicle: The bone extending from the breastbone (sternum) at the base of the front of the neck to the shoulder.

Cleft uvula: The uvula, the little V-shaped fleshy mass hanging from the back of the soft palate, is cleft. . Cleft uvula is a common minor anomaly occurring in about 1% of whites and 10% of Native Americans. Persons with a cleft uvula should not have their adenoids removed because, without the adenoids, they cannot achieve proper closure between the soft palate and pharynx while speaking and develop hypernasal speech. Also called bifid uvula.

Click-murmur syndrome: Mitral valve prolapse (also known as "Barlow’s syndrome"), the most common heart valve abnormality, affecting 5-10% of the world population. Most patients have no symptoms and require no treatment, but some have fatigue and/or palpitations. The mitral valve prolapse can often be detected by a doctor during examination of the heart and confirmed with an echocardiogram. Patients are usually given antibiotics prior to any procedure which might introduce bacteria into the bloodstream, including dental work and minor surgery, because of an increased risk of infection of the abnormal heart valve.

Clinical cytogenetics: The application of chromosome studies to clinical medicine. For example, clinical cytogenetic testing is done to see if a child with possible Down syndrome has an extra chromosome #21, as is most often the case. Clinical Cytogenetics is a specialty certified by the American Board Of Medical Genetics.

Clinical research trials: Evaluating the safety and effectiveness of medications or medical devices by monitoring their effects on large groups of people. Clinical medical trials sponsored by the U. S. government are listed on a web site of the National Institutes of Health (NIH). The NIH Clinical Center intends to make details of current clinical research studies for various diseases available over the Internet to increase opportunities for patients and physicians to participate in clinical investigations. The site is at http://www.cc.nih.gov/nihstudies/

Clinical trials: Medical research studies conducted with volunteers. Each study is designed to answer scientific questions and to find better ways to prevent, detect, or treat cancer.

Clitoris: A small mass of erectile tissue situated at the anterior apex of the vestibule.

Clone: Literally a fragment, the word in modern medical science has come to mean a replica, for example, of a group of bacteria or a macromolecule such as DNA. Clone also refers to an individual developed from a single somatic (non-germ) cell from a parent, representing an exact replica of that parent. A clone is a group of cells derived from a single ancestral cell.

Clone bank: Synonym for Genomic library.

Cloning: The process by which a genetically identical copy is made.

Cloning, cell: The process of producing a group of cells (clones), all genetically identical, from a single ancestor.

Cloning, DNA: The use of DNA manipulation procedures to produce multiple copies of a single gene or segment of DNA.

Clones, recombinant: Clones containing recombinant DNA molecules.

Clostridium difficile (C.difficile): A bacterium, one of the most common causes of infection of the large bowel (colon) in the U.S. affecting millions of people yearly. Patients taking antibiotics are at risk of becoming infected with C. difficile.Antibiotics disrupt the normal bacteria of the bowel, allowing C. difficile bacteria to become established in the colon. Many persons infected with C. difficile bacteria have no symptoms. These people become carriers of the bacteria and can infect others. In other people, a toxin produced by C. difficile causes diarrhea, abdominal pain, severe inflammation of the colon (colitis), fever, an elevated white blood count, vomiting and dehydration. In severely affected patients, the inner lining of the colon becomes severely inflamed (a condition called pseudomembranous colitis). Rarely, the walls of the colon wear away and holes develop (colon perforation), which can lead to a life-threatening infection of the abdomen.

Clot-dissolving medications: Agents such as plasminogen-activator (t-PA) and streptokinase that are effective in dissolving clots and re-opening arteries. Used, for example, in the treatment of heart attacks. Also called thrombolytic agents.

Clubfoot: A common malformation of the foot evident at birth. The medical term for the common ("classic") type of clubfoot is talipes equinovarus. The Latin word talipes was compounded from talus (ankle) + pes (foot) since, with a clubfoot, the foot is turned in sharply and the person seems to be walking on their ankle. Equino- indicates the heel is elevated (like a horse’s) and -varus indicates it is turned inward.

cM: A centimorgan, a unit of measure of genetic recombination frequency. One cM is equal to a 1% chance that a marker at one genetic locus will be separated from a marker at another locus due to crossing over in a single generation. In humans, 1 cM is equivalent, on average, to 1 million base pairs. The centimorgan is named after the pioneering (and Nobel Prize winning) geneticist Thomas Hunt Morgan.

CNS: Central nervous system.

CNS prophylaxis: Chemotherapy or radiation therapy to the central nervous system (CNS). This is preventative treatment. It is given to kill cancer cells that may be in the brain and spinal cord, even though no cancer has been detected there.

Cocci: pleural of coccus. Bacteria which are spherically shaped.

Coccus: a bacterial cell which has the shape of a sphere.

Coccyx: The small tail-like bone at the bottom of the spine very near to the anus.

Code: The genetic code is the correspondence between the triplet of bases in DNA with the amino acids. The discovery of the genetic code clearly ranks as one of the premiere events of what has been called the Golden Age of Biology (and Medicine).

Codon: A triplet of any three of chemical components in the genetic material called bases.

Coefficient of inbreeding: A statistical way of gauging how close two people are as to the genes. The coefficient of inbreeding (symbolized as F) is the probability that a person with two identical genes received both genes from an identical ancestor. Take first cousins who by definition share a set of grandparents. So for any particular allele (gene) in the father, the chance that the mother inherited the same allele from the same source is 1/8. Further, for any gene the father passes to his child, the chance is 1/8 that the mother has the same gene and ½ that she transmits that gene to the child so 1/8 X ½ = 1/16. Thus, a first-cousin marriage has a coefficient of inbreeding F =1/16. The added risks to the offspring of first cousins depend not only upon this coefficient of inbreeding but also upon the genetic family history and, in some cases, upon test results (for example, for beta thalassemia for first cousins of Italian descent). However, there are always added risks from the mating of closely related persons and those risks are not negligible.

Colchicine: A substance found in a plant that is used in clinical medicine for the tr