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Sabin vaccine: Oral Polio virus Vaccine (OPV). The polio virus in OPV is attenuated (weakened). The Sabin vaccine is named after the American virologist Albert Sabin. See Immunization, polio.

Sagittal: A vertical plane passing through the body which divides it into left and right sides.

Salivary: Glands in the mouth that produce saliva. The salivary glands can become inflamed in diseases, such as Sjogren's syndrome and mumps.

Salk vaccine: Inactivated Polio Vaccine (IPV). The polio virus in IPV has been inactivated (killed). The Salk vaccine is named after the American physician-virologist Jonas Salk. See Immunization, polio.

Salpingo-oophorectomy: Removal of the fallopian tubes and ovaries.

Sapphism: Female homosexuality. Named after the poet Sappho who lived on the Greek island of Lesbos (circa 600 BC). She was a lesbian by geography and sexual orientation. Also called lesbianism.

Sarcoma: A type of cancer that starts in bone or connective tissue.

Satellite DNA: DNA that contains many tandem (not inverted) repeats of a short basic repeating unit. Satellite DNA is located at very specific spots in the genome (on chromosomes 1, 9, 16 and the Y chromosome, the tiny short arms of chromosomes 13-15 and 21 and 22, and near the centromeres of chromosomes).

Scalded skin syndrome: A potentially serious side effect of infection with the Staph (Staphylococcus) bacteria that produces a specific protein which loosens the "cement" holding the various layers of the skin together. This allows blister formation and sloughing of the top layer of skin. If it occurs over large body regions it can be deadly (just like a large surface area of the body having been burned). It is necessary to treat scalded skin syndrome with intravenous antibiotics and to protect the skin from allowing dehydration to occur if large areas peel off. The disease occurs predominantly in children under 5 years of age. It is known formally as Staphyloccoccal scalded skin syndrome and as Ritter disease.

Schistosoma haematobium: A species of trematode worm that parasitizes humans and causes urinary tract disease. See Schistosomiasis.

Schistosoma japonicum: A species of trematode worm that parasitizes humans and that (like S. mansoni) causes liver and gastrointestinal tract disease. See Schistosomiasis.

Schistosoma mansoni: A species of trematode worm that parasitizes humans and that (like S. japonicum) causes liver and gastrointestinal tract disease. See Schistosomiasis.

Schistosomiasis: Disease of liver, gastrointestinal tract and bladder caused by trematode worms that parasitize people. The infection is acquired from infested water. Three main species of these trematode worms (flukes)--Schistosoma haematobium, S. japonicum, and S. mansoni—cause disease in humans. Larval forms of the parasite live in freshwater snails. The cercaria (form of the parasite) is liberated from the snail burrow into skin, transforms to the schistosomulum stage, and migrates to the urinary tract (S. haematobium), liver or intestine (S. japonicum, S.mansoni) where the adult worms develop. Eggs are shed into the urinary tract or the intestine and hatch to form miracidia (yet another form of the parasite) which then infect snails, completing the life cycle of the parasite. Adult schistosome worms can seriously damage tissue. Schistosome species which cannot live in man cause swimmer’s itch. Schistosomiasis is also called bilharzia after the shortlived German physician Theodor Bilharz (1825-1862)

Schizophrenia: The most common form of psychosis, characterized by partial or total withdrawal of interest in the world outside of oneself and loss of intellectual and emotional function.

Sciatica: Pain resulting from irritation of the sciatic nerve, typically felt at the back of the thigh. The sciatic nerve is the largest nerve in the body and begins from nerve roots in the lumbar spinal cord in the low back and extends through the buttock area to send nerve endings down the lower limbs. While sciatica is most commonly a result of a disc herniation directly pressing on the nerve, any cause of irritation or inflammation of this nerve can reproduce the symptoms of sciatica.

Sclerencephaly: A general term for scarring and shrinkage of the substance of the brain. Sclerencephaly occurs because of chronic inflammation of the brain matter.

Sclerosis, multiple (MS): The National Multiple Sclerosis Society says of MS that it is "a disease that randomly attacks your central nervous system, wearing away the control you have over your body. Symptoms may range from numbness to paralysis and blindness. The progress, severity and specific symptoms cannot be foreseen. You never know when attacks will occur, how long they will last, or how severe they will be. Most people are diagnosed with MS between the ages of 20 and 40...." In medical terms, MS involves demyelinization of the white matter sometimes extending into the gray matter. Demyelinization is loss of myelin, the coating of nerve fibers composed of lipids (fats) and protein that serves as insulation and permits efficient nerve fiber conduction. The "white matter" is the part of the brain which contains myelinated nerve fibers and appears white, whereas the gray matter is the cortex of the brain which contains nerve cell bodies and appears gray. When myelin is damaged in MS, nerve fiber conduction is faulty or absent. Impaired bodily functions or altered sensations associated with those demyelinated nerve fibers give rise to the symptoms of MS. Recent research (1998) has also identified nerve cell death as part of the nervous system injury in MS.

Scoliosis: Sideways (lateral) curvature of the spine. Scoliosis is usually an incidental and harmless finding. When severe, scoliosis can be improved by surgical correction.

Score, Apgar: A practical method to assess a newborn infant, the Apgar score is a number arrived at by scoring the heart rate, respiratory effort, muscle tone, skin color, and response to a catheter in the nostril. Each of these objective signs can receive 0, 1, or 2 points. An Apgar score of 10 means an infant is in the best possible condition.. The Apgar score is done routinely 60 seconds after the complete birth of the infant. An infant with a score of 0-3 needs immediate resusitation. The Apgar score is commonly repeated 5 minutes after birth and in the event of a difficult resusitation, the Apgar may be done again at 10, 15, and 20 minutes. An Apgar score of 0-3 at 20 minutes of age is predictive of high morbidity (disease) and mortality. The score is named for the American anesthesiologist Virginia Apgar (1909-1974) at Columbia University in New York who originated the scoring method.

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

Scrotum: A pouch of skin which contains the testes, epididymides, and lower portions of the spermatic cords.

Scrub typhus: A mite-borne infectious disease caused by a microorganism, Rickettsia tsutsugamushi, characteristically with fever, headache, a raised (macular) rash, swollen glands (lymphadenopathy) and a dark crusted ulcer (called an eschar or tache noire) at the site of the chigger (mite larva) bite. This disease occurs in the area bounded by Japan, India, and Australia. Known also as Tsutsugamushi disease, mite-borne typhus, and tropical typhus.

Sebaceous cyst: A sebaceous cyst is a rounded swollen area of the skin formed by an abnormal sac of retained excretion (sebum) from the sebaceous follicles.

Sebaceous gland: A normal gland of the skin which empties an oily secretion into the hair follicle near the surface of the skin.

Seborrhea: A accumulation of scales of greasy skin, often on the scalp. Dandruff.

Seborrheic keratosis: A benign skin lesion resulting from excessive growth of the top layer of skin cells. It usually is found in persons over 30 years old and may be few or numerous.

Sebum: An oily secretion of the sebaceous gland which helps to preserve the flexibility of the hair.

Secretin: Hormone made by glands in the small intestine that stimulates pancreatic secretion. The word "hormone" was coined by the English physiologists Wm. M. Bayliss and Ernest H. Starling in connection with their discovery of secretin, the first hormone, in 1902.

Section (anatomic): A slice of tissue. A biopsy obtained by surgery is usually sectionned (sliced). And all the "sections" under the microscope might, for example, reveal entirely benign cells with no hint of cancer.

Section (obstetrical): Short for a Caesarian section. In surgery, the word "section" refers to the division of tissue. Here, the division of tissue involves the abdominal wall of the mother and the wall of the uterus which are "sectionned" in order to deliver the baby from the uterus (womb).

Section, Caesarian: Procedure in which an infant, rather than being born vaginally, is surgically removed from the uterus. As the name "Caesarian" suggests, this is not a new procedure. it was done in ancient civilizations upon the death of a pregnant woman near term to salvage the baby. Julius Caesar (or, more likely, one of his predecessors) was born by this procedure. The term "section" in surgery refers to the division of tissue. What is being divided here is the abdominal wall of the mother and 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 is the only agent capable of destroying Macbeth. He kills Macbeth in battle.

Section, cross: A transverse cut through a structure. The opposite is a longitudinal section.

Section, longitudinal: A cut along the long axis of a structure

Sedimentation rate: A sedimentation rate, or "sed rate", is a blood test that detects and monitors inflammation activity. It is measured by recording the rate at which red blood cells (RBCs) sediment in a tube over time. It increases (the RBCs sediment faster) with more inflammation.

Segawa’s dystonia: An important variant of dopa-responsive dystonia (DRD). Typically, DRD begins in childhood or adolescence with progressive difficulty in walking and, in some cases, spasticity. In Segawa’s dystonia, the symptoms fluctuate during the day from relative mobility in the morning to increasingly worse disability in the afternoon and evening as well as after exercise.

Seizure: A seizure is a sudden attack of epileptic convulsion. It is a result of involuntary electrical activity in the brain. It can be associated with uncontrolled motor (movement) or sensory system action. Accordingly, a patient suffering a seizure may experience uncontrollable body movements, unusual smells or tastes and have loss of consciousness (awareness of surroundings).

Seizure, causes of: Known causes of seizures include head injuries, brain tumors, lead poisoning, maldevelopment of the brain, genetic and infectious illnesses. But in fully half of the patients with seizures, no cause can be found.

Selective Estrogen-Receptor Modulator (SERM): A "designer estrogen" which possesses some, but not all, of the actions of estrogen. For example, raloxifene (trade name EVISTA) is classified as a SERM because it prevents bone loss (like estrogen) and lowers serum cholesterol (like estrogen) but (unlike estrogen) does not stimulate the endometrial lining of the uterus.

Selenium: An essential mineral that is a component of a key antioxidant enzyme, glutathione reductase, in tissue respiration. Deficiency of selenium causes Keshan disease, a fatal form of cardiomyopathy (disease of the heart muscle) first observed in Keshan province in China and since found elsewhere. According to the National Academy of Sciences, the Recommended Dietary Allowances of selenium are 70 milligrams per day for men and 55 milligrams per day for women. Food sources of selenium include seafoods, some meats such as kidney and liver, and some grains and seeds. Too much selenium may cause reversible changes in the hair (balding) and nails, garlic odor to the breath, intestinal distress, weakness and slower mentation (slowed mental functioning).

Selenium deficiency: Deficiency of the essential mineral selenium causes Keshan disease, a fatal form of cardiomyopathy (disease of the heart muscle) first observed in Keshan province in China and since found elsewhere. According to the National Academy of Sciences, the Recommended Dietary Allowances of selenium are 70 milligrams per day for men and 55 milligrams per day for women. Food sources of selenium include seafoods, some meats such as kidney and liver, and some grains and seeds

Selenium excess: Too much of the mineral selenium may cause reversible changes in the hair (balding) and nails, garlic odor to the breath, intestinal distress, weakness and slower mentation (slowed mental functionning). According to the National Academy of Sciences, the Recommended Dietary Allowances of selenium are 70 milligrams per day for men and 55 milligrams per day for women.

Seminal vesicles: Two structures about 5 cm long behind the bladder and above the prostate gland which contribute fluid to the ejaculate.

Septal defect, atrial (ASD): A hole in the septum, the wall, between the atria, the upper chambers of the heart. Commonly called an ASD. ASDs are a major class of heart deformity that is present at birth (congenital cardiac malformation).

Septal defect, ventricular (VSD): A hole in the interventricular septum, the wall between the ventricles, the lower chambers of the heart. Commonly called a VSD. VSDs are a common class of heart deformity that is present at birth (congenital cardiac malformation)..

Septate: Divided: A septate uterus is a one that is divided.

Septate vagina: A vagina that is divided, usually longitudinally, to create a double vagina. This situation can be easily missed by the patient and even by the doctor on exam. If the patient becomes sexually active prior to diagnosis, one of the vaginas stretches and becomes "dominant". The other vagina slips slightly upward and flush and is a little difficult to enter.

Septic bursitis: A bursa is a closed fluid-filled sac that functions as a gliding surface to reduce friction between tissues of the body. When the bursa becomes inflamed, the condition is known as "bursitis." When the bursa is infected with bacteria, the condition is called septic bursitis.

Septum: A word borrowed from the Latin "saeptum" meaning a "dividing wall or enclosure."

Septum, interatrial: The wall separating the upper chambers (the atria) of the heart. A hole in the interatrial septum is termed an atrial septal defect (ASD).

Septum, interventricular: The wall separating the lower chambers (the ventricles) of the heart. A hole in the interventricular septum is termed a venticular septal defect (VSD).

Septum, nasal: The dividing wall that runs down the middle of the nose so that there are normally two sides to the nose, each ending in a nostril.

Sequence, complementary: Nucleic acid sequence of bases that can form a double- stranded structure by matching base pairs. For example, the complementary sequence to C-A-T-G (where each letter stands for one of the bases in DNA) is G-T-A-C.

Sequence, conserved: A base sequence in a DNA molecule (or an amino acid sequence in a protein) that has remained essentially unchanged throughout evolution.

Sequence, regulatory: A sequence of bases in DNA that controls the expression of a gene.

Sequence tagged site (STS): A short (200 to 500 base pairs) DNA sequence that occurs but once in the human genome and whose location and base sequence are known. Detectable by polymerase chain reaction, STSs are useful for localizing and orienting the mapping and sequence data reported from many different laboratories and serve as landmarks on the developing physical map of the human genome. Expressed sequence tags (ESTs) are STSs derived from comlementarty DNAs (cDNAs).

Sequencing: Learning the order of nucleotides (base sequences) in a DNA or RNA molecule or the order of amino acids in a protein.

SERM: Selective Estrogen-Receptor Modulator.

Serositis: Inflammation of the serous tissues of the body. The serous tissues line the lungs (pleura), heart (pericardium), and the inner lining of the abdomen (peritoneum) and organs within.

Serotonin: A chemical in the brain involved in the transmission of nerve impulses. Serotonin.can trigger the release of substances in the blood vessels of the brain that in turn cause the pain of the migraine.

Serum: The clear liquid that separates from clotted blood. Serum differs from plasma, the liquid that separates from unclotted blood. "Serum" is the Latin word for "whey", the watery liquid that separates from the curds in > cheesemaking.

Serum hepatitis: An obsolete term. See Hepatitis B.

Sexually transmitted disease (STD): Any disease transmitted by sexual contact. Examples: gonorrhea, syphilis, AIDS.. The older term was venereal disease.

Sexually transmitted diseases in women: Gonorrhea and chlamydia are bacterial sexually transmitted diseases (STDs) frequently found together. Gonorrhea is NOT transmitted from toilet seats. Women infected with it may not have any symptoms but can end up later with severe pelvic infection. Early syphilis causes a mouth or genital ulcer (chancre) and later can cause hair loss, headaches, sore throat, and skin rash. Even later, syphilis can lead to heart and brain damage. Genital herpes is a viral infection that can cause painful genital sores. Genital warts are caused by viruses and can increase a woman’s risk for cancer of the cervix. AIDS is caused by the human immunodeficiency virus (HIV). Hepatitis B is a virus that causes liver inflammation and can lead to cirrhosis and cancer of the liver. Hepatitis B can now be prevented with a vaccine. There is no "safe" sex. Condoms do not necessarily prevent STDs.

Shell shock: The World War I name for what is known today as post-traumatic stress, this is a psychological disorder that develops in some individuals who have had major traumatic experiences (and, for example, have been in a serious accident or through a war). The person is typically numb at first but later has symptoms including depression, excessive irritability, guilt (for having survived while others died), recurrent nightmares, flashbacks to the traumatic scene, and overreactions to sudden noises. Post-traumatic stress became known as such in the 70s due to the adjustment problems of some Vietnam veterans.

Shin bone fever: A louse-borne disease first recognized in the trenches of World War I, again a major problem in the military in World War II, seen endemically in Mexico, N. Africa, E, Europe, and elsewhere. The cause, Rochalimaea quintana, is an unusual rickettsia that multiplies in the gut of the body louse. Transmission to people can occur by rubbing infected louse feces into abraded (scuffed) skin or conjunctiva (whites of the eyes). Onset of symptoms is sudden, with high fever, headache, back and leg pain and a fleeting rash. Recovery takes a month or more. Relapses are common. Also called trench fever, Wolhynia fever, quintan fever, five-day fever, Meuse fever, His’ disease, His-Werner disease, Werner-His disease.

Shingles: Shingles is an acute infection by a virus called Herpes zoster, which causes an eruption of vesicles in the skin. The eruption is usually distributed along the area of the skin that is innervated by a nerve that supplies sensation. The pain associated with shingles is, in part, related to inflammation of the associated sensory nerve.

Shock: In medicine, shock is a critical condition brought on by a sudden drop in blood flow through the body. There is failure of the circulatory system to maintain adequate blood flow. This sharply curtails the delivery of oxygen and nutrients to vital organs. It also compromises the kidney and so curtails the removal of wastes from the body. Shock can be due to a number of different mechanisms including not enough blood volume (hypovolemic shock) and not enough output of blood by the heart (cardiogenic shock). The signs and symptoms of shock include low blood pressure (hypotension), overbreathing (hyperventilation), a weak rapid pulse, cold clammy grayish-bluish (cyanotic) skin, decreased urine flow (oliguria), and mental changes (a sense of great anxiety and forboding, confusion and, sometimes, combativeness). Shock is a major medical emergency.

Shock, cardiogenic: Shock caused by heart failure. The heart fails to pump blood effectively. For example, a heart attack (a myocardial infarction) can cause an abnormal ineffectual heart beat (an arhythmia) with very slow, rapid, or irregular contractions of the heart, impairing the heart’s ability to pump blood, lowering the volume of blood going to vital organs. Cardiogenic shock can also be due to drugs that reduce heart function or an abnormally low level oxygen in the blood (hypoxemia) caused, for instance, by lung disease. Whatever be the cause, blood vessels constrict and adrenalin-like substances are secreted into the bloodstream, increasing the heart rate. Treatment of cardiogenic shock is aimed at improving the heart’s function. Shock after a heat attack is extremely serious. The mortality rate is over 80%.

Shock, hypovolemic: Shock due to a decrease in blood volume. This is the #1 cause of shock. It can be due to loss of blood from bleeding, loss of blood plasma through severe burns, and dehydration. The treatment, first and foremost, is prompt intravenous administration of fluid.

Shock, psychologic: Trauma due to psychological events, as in "shell shock" (now known as post-traumatic stress disorder).

Shock, shell: The World War I name for what is known today as post-traumatic stress, this is a psychological disorder that develops in some individuals who have had major traumatic experiences (and, for example, have been in a serious accident or through a war). The person is typically numb at first but later has symptoms including depression, excessive irritability, guilt (for having survived while others died), recurrent nightmares, flashbacks to the traumatic scene, and overreactions to sudden noises. Post-traumatic stress became known as such in the 70s due to the adjustment problems of some Vietnam veterans.Shots, allergy: Known medically as allergy desensitization or allergy immunotherapy, the injections are designed to stimulate the immune system with gradually increasing doses of the substances to which a person is allergic, the aim being to modify or stop the allergy "war" (by reducing the strength of the IgE and its effect on the mast cells). This form of treatment is very effective for allergies to pollen, mites, cats, and especially stinging insects (eg, bees, hornets, yellowjackets, wasps, velvet ants, fire ants). Allergy immunotherapy usually takes 6 months to a year to become effective and injections are usually required for 3-5 years.

Shock, toxic: See Syndrome, toxic shock.

Shots, allergy: Known medically as allergy desensitization or allergy immunotherapy, the injections are designed to stimulate the immune system with gradually increasing doses of the substances to which a person is allergic, the aim being to modify or stop the allergy "war" (by reducing its effect on the mast cells). This form ofhe strength of the IgE and its treatment is very effective for allergies to pollen, mites, cats, and especially stinging insects (eg, bees, hornets, yellowjackets, wasps, velvet ants, fire ants). Allergy immunotherapy usually takes 6 months to a year to become effective and injections are usually required for 3-5 years.

Shoulder bursitis: A bursa is a fluid-filled sac that functions as a gliding surface to reduce friction between moving tissues of the body. There are two major bursae of the shoulder. Bursitis is usually not infectious, but the bursa can become infected. Treatment of non-infectious bursitis includes rest, ice, and medications for inflammation and pain. Infectious bursitis is treated with antibiotics, aspiration, and surgery.

Show: An appearance.

Show, bloody: Literally, the appearance of blood. The bloody show consists of blood-tinged mucus created by extrusion and passage of the mucous plug that filled the cervical canal (the canal between the vagina and uterus) during pregnancy. The bloody show is a classic sign of impending labor. The same term, bloody show, can be applied to the beginning of menstruation.

Shprintzen syndrome: Congenital malformation (birth defect) syndrome with cleft palate, heart defect, abnormal face, and learning problems. The condition is also called the velo-cardio-facial (VCF) syndrome. (The velum is the soft palate). Other less frequent features include short stature, small-than-normal head (microcephaly), mental retardation, minor ear anomalies, slender hands and digits, and inguinal hernia. The cause is usually a microdeletion in chromosome band 22q11.2, just as in DiGeorge syndrome. Shprintzen and DiGeorge syndromes are different clinical expressions of essentially the same chromosome defect.

Shulman’s syndrome (Eosinophilic fasciitis): A disease which leads to inflammation and thickening of the skin and fascia. (The fascia is a lining tissue under the skin that covers a surface of underlying tissues. When the fascia is inflamed, the condition is referred to as "fasciitis.") In eosinophilic fasciitis, the involved fascia is inflamed with the eosinophil white blood cells. There is progressive thickening, and often redness and warmth, and hardness of the skin surface.

Shunt: A catheter (tube) that carries cerebrospinal fluid from a ventricle in the brain to another area of the body.

Side effects: Problems that occur when treatment affects healthy cells. Common side effects of cancer treatment are fatigue, nausea, vomiting, decreased blood cell counts, hair loss, and mouth sores.

SIDS (Sudden Infant Death Syndrome): The sudden and unexpected death of a baby with no known illness, typically affecting infants from 2 weeks to 6 months of age while sleeping. At elevated risk for SIDS are children with a brother or sister who died of SIDS; babies whose mothers smoked or used heroin, methadone, or cocaine during pregnancy; infants born weighing less than 4.4 pounds (2000 grams); children with an abnormal breathing pattern with long periods without taking a breath (apnea); and babies who sleep on their stomachs. Since babies who sleep on their stomachs are at least 3 times more likely to die of SIDS than babies who sleep on their backs, children’s health authorities such as the American Academy of Pediatrics recommend always placing infants on their backs to sleep.

Sigmoidoscope: A lighted instrument used to view the inside of the lower colon.

Sigmoidoscopy: Sigmoidoscopy is a procedure whereby a doctor inserts a viewing tube (sigmoidoscope) into the rectum for the purpose of inspecting the lower colon (sigmoid colon) and rectum. If an abnormal area is detected, a biopsy can be performed.

Sign: Any abnormality, such as a change in appearance, sensation, or function, observed by a physician when evaluating a patient which indicates a disease process.

Single-gene diseases: Hereditary disorders caused by a change (mutation) in a single gene. There are thousands of single-gene diseases including achondroplastic dwarfism, Huntington disease, cystic fibrosis, sickle cell disease, Duchenne muscular dystrophy, and hemophilia. Single-gene diseases typically describe classic simple Mendelian patterns of inheritance (as autosomal dominant, autosomal recessive, and X-linked traits) by comparison with polygenic diseases.

Sino-atrial node: See SA node.

Sinus tachycardia: Fast heartbeat (tachycardia) occurring because of rapid firing by the SA node, the natural pacemaker of the heart. Electrical signals initiated in the SA node are transmitted to the atria and the ventricles to stimulate heart muscle contractions heartbeats. Sinus tachycardia is usually a rapid contraction of a normal heart in response to a condition, drug, or disease as, for examples, pain, fever, excessive thyroid hormone, exertion, excitement, low blood oxygen level (hypoxia), or stimulant drugs such as caffeine, cocaine, and amphetamines. However, in some cases, it can be a sign of heart failure, heart valve disease, or other illness.

Sinusitis: Sinusitis is inflammation of the lining membrane of any of the hollow areas (sinuses) of the bone of the skull around the nose. The sinuses are directly connected to the nasal cavities.

Situs inversus totalis: A condition in which there is complete transposition (right to left reversal) of the thoracic and abdominal organs. The heart is not in its usual position in the left chest but is on the right. Specifically related to the heart, this is referred to as dextrocardia (literally, right-hearted). And the stomach, which is normally in the left upper abdomen, is on the right. In patients with situs inversus totalis, all of the chest and abdominal organs are reversed and appear in mirror image when examined or visualized by tests such as x-ray filming. Situs inversus totalis has been estimated to occur once in about 6-8,000 births. Situs inversus occurs in a rare abnormal condition that is present at birth (congenital) called Kartagener’s syndrome.

Sixth disease: A viral disease of infants and young children with sudden onset of high fever which lasts several days and then suddenly subsides leaving in its wake a fine red rash. The causative agent is herpesvirus type 6 so the disease is known as Sixth Disease. Also known as Exanthem subitum (sudden rash), Pseudorubella, Roseola, Roseola infantilis, and Roseola infantum.

Skeletal dysplasia: One of a large contingent of genetic diseases in which the bony skeleton is abnormally formed during development. For example, achondroplasia (achondroplastic dwarfism).

Skeletal muscle: One of three types of muscle tissue in the body (skeletal, smooth, cardiac) which represents the majority of the muscular tissue in the body. Skeletal muscle is the type of muscle which powers movement of the skeleton as in walking and lifting.

Skeleton: The skeleton is composed of bones and is the framework of the body.

Skin graft: Skin that is moved from one part of the body to another.

Skin, scalded, syndrome: See Scalded skin syndrome.

Skin test for allergy: Test done on the skin to identify the allergy substance (allergen) triggering the allergic reaction. A small amount of the suspected allergy substance is placed on the skin. The skin is then gently scratched through the small drop with a special sterile needle. If the skin reddens and, more importantly, swells, then allergy to that substance is probable.

Skull: The skull is a collection of bones which encases the brain and gives form to the head and face. These bones include the following - frontal, parietal, occipital, temporal, sphenoid, ethmoid, zygomatic, maxilla, nasal, vomer, palatine, inferior concha, and mandible.

Slanted ear: An ear that is slanted more than usual. Technically, an ear is slanted when the angle of the slope of the auricle is more than 15 degrees from the perpendicular. Considered a minor anomaly. The presence of 2 or more minor anomalies in a child increases the probability that the child has a major malformation.

Sleep apnea: Temporary stoppage of breathing during sleep, often resulting in daytime sleepiness.

Small cell lung cancer: A type of lung cancer in which the cells are small and round. Also called oat cell lung cancer.

Small intestine: The part of the digestive tract that extends from the stomach to the large intestine.

Smoldering leukemia: A condition in which the bone marrow does not function normally. It does not produce enough blood cells. This condition may progress and become acute leukemia. Smoldering leukemia also is called myelodysplastic syndrome or preleukemia.

Smooth muscle: One of the three types of muscle tissue in the body (skeletal, smooth, cardiac). Generally forms the supporting tissue of blood vessels and hollow internal organs such as the stomach, intestine, and bladder. So named because of the absence of microscopic lines called "cross-striations" which are seen in the other two types.

Snoring: During normal breathing, air passes through the throat en route to the lungs and travels by the tongue, soft palate (the back of the roof of the mouth), uvula (the prominent anatomic structure dangling downward visibly at the back of the mouth), and tonsils. When a person is awake, the muscles in the back of the throat tighten to hold these structures in place and prevent them from collapsing and vibrating in the airway. During sleep, the uvula and soft palate frequently vibrate causing the sounds of snoring.

Soft palate: The muscular part of the roof of the mouth. The soft palate is directly behind the hard palate. It lacks bone and so is soft.

Soft tissue sarcoma: A sarcoma that begins in the muscle, fat, fibrous tissue, blood vessels, or other supporting tissue of the body. Not a type of bone cancer.

Somnoplasty: A surgical treatment for snoring. Somnoplasty uses heat energy to remove tissues of the uvula and soft palate. (See: Snoring). Somnoplasty is usually done as an office procedure with local anesthesia. It is not indicated for the treatment of sleep apnea.

Spasmodic dysphonia: Involves the muscles of the throat that control speech. Also called spastic dysphonia or laryngeal dystonia, it causes strained and difficult speaking or breathy and effortful speech.

Spastic colitis: See Syndrome, irritable bowel.

Spastic pseuodoparalysis: Better known as Creutzfeldt-Jakob disease (CJD). A dementing disease of the brain. It is believed due to an unconventional (not a bacteria or virus), transmissible agent called a prion. Symptoms of CJD include forgetfulness, nervousness, jerky trembling hand movements, unsteady gait, muscle spasms, chronic dementia, balance disorder, and loss of facial expression. CJD is classified as a spongiform encephalopathy. Most cases occur randomly (sporadically), but inherited forms exist. There is neither treatment nor cure for CJD. Other names for CJD include Creutzfeldt-Jakob syndrome and Jakob-Creutzfeldt disease.

Speculum: An instrument used to widen the opening of the vagina so that the cervix is more easily visible.

Speech pathologist: A specialist who evaluates and treats people with communication and swallowing problems. Also called a speech therapist.

Sperm: A sperm is the male "gamete" or sex cell. It combines with the female "gamete," called an ovum, to form a zygote. The formation process is called "fertilization." (see ovum, zygote).

Spermatic cord: A group of structures which go through the inguinal canal to the testis. The structures include the vas deferens, arteries, veins, lymphatic vessels, and nerves.

Spina bifida: A bony defect in the vertebral column through which the meningeal membrane and spinal cord may protrude (spina bifida cystica) or may not protrude so that the defect remains hidden, covered by skin (spina bifida occulta). Spina bifida cystica, also known as meningomyelocele (MM), is due to failure of closure during embryonic life of bottom end of the neural tube, the structure which gives rise to the central nervous system (the brain and spinal cord). The term spina bifida refers specifically only to the bony defect in the vertebral column but, through usage, the term spina bifida is gradually becoming synonymous with MM. The risk of spina bifida (and all neural tube defects) can be decreased by the mother eating ample folic acid during pregnancy.

Spina bifida cystica: A bony defect in the vertebral column through which the meningeal membranes that cover the spinal cord and part of the spinal cord protrude. An alternative term is meningomyelocele.

Spina bifida occulta: Literally, a hidden cleft in the spine. A bony defect in the vertebral column which remains hidden, covered by skin

Spine: Commonly, a reference to the bony building blocks of bone (vertebral column) surrounding and protecting the spinal cord. The spine can be categorized according to level of the body, i.e., cervical spine (neck), thoracic spine (upper and mid-back), and lumbar spine (low back). A spine also refers to a short prominence of bone. It is the spines of the vertebrae that we can feel protruding at the base of the back of our neck and in the middle of our backs. These spines protect our spinal cord from injury from behind.

Spirochete: A microscopic bacterial organism, a spirochete apperars worm-like, spiral-shaped, and wiggles vigorously when viewed under a microscope. Treponema pallidum, the cause of syphilis, is a particularly well-known member of the Spirochaeta family. The term spirochete is an odd hybrid of Greek and Latin roots, the Latin "spira" for "coil" and the Greek "chaite" for "long flowing hair," formed because the spirochete looked like a coil of hair.

Spleen: The spleen is a blood vessel filled organ located in the upper left abdominal cavity. It is a storage organ for red blood cells and contains many specialized white blood cells called "macrophages" which act to filter blood.

Spleen, ruptured: Rupture of the capsule of the spleen, an organ in the upper left part of the abdomen, is a potential catastrophe that requires immediate medical and surgical attention. Splenic rupture permits large amounts of blood to leak into the abdominal cavity which is severely painful.and life-threatening. Shock and, ultimately, death can result. Patients typically require an urgent operation. Rupture of a normal spleen can be caused by trauma, for example, in an accident. If an individual’s spleen is enlarged, as is frequent in mononucleosis, most physicians will not allow activities (such as major contact sports) where injury to the abdomen could be catastrophic.

Splenectomy: An operation to remove the spleen.

Splenic fever: Known also as anthrax, splenic fever 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."

Spondylolisthesis: Forward movement of one building block of the spine (vertebra) in relation to an adjacent vertebra.

Spotted fever: Rocky Mountain spotted fever (RMSF):, an acute febrile (feverish) disease initially recognized in the Rocky Mountain states, caused by Rickettsia rickettsii transmitted by hard-shelled (ixodid) ticks. Occurs only in the Western Hemisphere. Anyone frequenting tick-infested areas is at risk for RMSF. Onset of symptoms is abrupt with headache, high fever, chills, muscle pain. and then a rash. The rickettsiae grow within damaged cells lining blood vessels which may become blocked by clots. Blood vessel inflammation (vasculitis) is widespread Early recognition of RMSF and prompt antibiotic treatment is important in reducing mortality. Also called tick fever, and tick typhus.

Sprue, nontropical: This condition results from an immune (allergic) reaction to gluten, a protein found in wheat and related grains and present in many foods that we eat. 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 diagnostic test for sprue is a biopsy of the involved small bowel. Treatment is to avoid gluten in the diet. Medications are used for refractory (stubborn) sprue. Known under a number of other names, including celiac sprue.

Spurs, heel: Pointed bony outgrowths at the back of the heel or under the heel beneath the sole of the foot. Heel spurs at the back of the heel are associated with inflammation of the Achilles tendon (tendinitis) and cause tenderness and pain at the back of the heel made worse while pushing off the ball of the foot.

Sputum: Mucus from the lungs.

Squamous cells: Flat cells that look like fish scales; they make up most of the epidermis, the outer layer of the skin.

Squamous cell carcinoma: Cancer that begins in squamous cells, which are thin, flat cells resembling fish scales. Squamous cells are found in the tissue that forms the surface of the skin, the lining of the hollow organs of the body, and the passages of the respiratory and digestive tracts.

Squamous intraepithelial lesion: A general term for the abnormal growth of squamous cells on the surface of the cervix. The changes in the cells are described as low grade or high grade, depending on how much of the cervix is affected and how abnormal the cells are. Also called SIL.

Stage: The extent of a cancer, especially whether the disease has spread from the original site to other parts of the body.

Staging: Doing exams and tests to learn the extent of a cancer, especially whether it has spread from its original site to other parts of the body.

STD: Sexually transmitted disease.

STDs in women: See Sexually transmitted diseases in women.

Staph: Very commonly used shortened form of Staphylococcus, a very common and important group of bacteria. See Staphylococcus.

Staphyloccoccal scalded skin syndrome: See Scalded skin syndrome.

Staphylococcus: A group of bacteria, familiarly known as Staph, that can > (and do) cause a multitude of diseases. The name comes from the Greek staphyle meaning a bunch of grapes + kokkos meaning berry, and that is exactly what Staph look like under the microscope, like a bunch of grape or little round berries. (In technical terms, these are gram-positive, facultative anaerobic, usually unencapsulated cocci). Staph can cause illness directly by infection or indirectly through products they make such as toxins responsible for food poisoning and toxic shock syndrome.

STAT: A common medical abbreviation which is used to imply urgent or rush. It is derived from a latin word "statim" which means immediately.

Stein-Leventhal syndrome: Known descriptively as polycystic ovarian disease (PCO), this syndrome is basically an hormonal problem that causes women to have a variety of symptoms including irregular or no periods, acne, obesity and excessive hair growth. Women with PCO are at a higher risk for uterine cancer (endometrial cancer), diabetes, high blood pressure, and heart disease. With proper treatment, risks can be minimized. The syndrome is named after the late American gynecologists Irving F. Stein, Sr. and Michael Leo Leventhal.

Stereotaxis: Use of a computer and scanning devices to create three-dimensional pictures. This method can be used to direct a biopsy, external radiation, or the insertion of radiation implants.

Steroids: A large group of chemical substances classified by chemical structure. Steroids include drugs used to relieve swelling and inflammation (such as prednisone), vitamin D, and sex steroids (such as testosterone).

Still’s disease: Also known as systemic-onset juvenile rheumatoid arthritis and systemic-onset juvenile chronic arthritis. Still’s disease presents with systemic (bodywide) illness including high intermittent fever, a 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 immediately apparent but it does appear in time and may persist after the systemic symptoms are gone. Still’s disease, adult-onset: (See Still’s disease.) Although Still’s disease was first described in children, it is known to occur in adults.

Stings, insect: Stings from large stinging insects such as yellow jackets, bees, hornets and wasps can trigger allergic reactions varying greatly in severity. Avoidance and prompt treatment are essential. In selected cases, allergy injection therapy is highly effective. (The three "A’s" of insect allergy are Adrenaline, Avoidance and Allergist.)

Stoma: An opening into the body from the outside created by a surgeon.

Stomach: A muscular pouch that helps in the digestion of food by mixing it with digestive juices and churning it into a thin liquid.

Stomach cancer: 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 and weight. The cancer is diagnosed with a biopsy of stomach tissue during a procedure.

Stomach flu: A misnomer that has nothing to do with influenza (flu) virus, the term "stomach flu" is sometimes used to describe gastrointestinal illnesses caused by other microorganisms.

Stomach, Pavlov: A pouch fashioned surgically from part of the stomach (but isolated from the rest of the stomach) that opens via a fistula (canal) on to the abdominal wall. At different points along the dogs’ digestive tracts, the Russian physiologist Ivan Petrovich Pavlov (1848-1936) surgically created pockets ("Pavlov pouches") from which he could obtain secretions, the aim being to study the physiology of the digestive tract. He did so from the salivary glands down to the stomach, liver and pancreas with considerable success and in 1904 (the 4th year it was awarded) he received the Nobel Prize for "his work on the physiology of digestion, through which knowledge on vital aspects of the subject has been transformed and enlarged."

Stool: The solid matter discharged in a bowel movement.

Stool test: A test to see whether there is blood in the bowel movement. Also called a fecal occult blood test: A test to check for hidden blood in stool. (Fecal refers to stool. Occult means hidden.)

Strep: Very commonly used shortened form of Streptococcus, a very common and important group of bacteria. See Streptococcus

Strep throat: An infection caused by a type of bacteria called streptococcus, which can lead to serious complications if not adequately treated.

Streptococcus: A group of bacteria, familiarly known as strep, that can > (and do) cause a multitude of diseases. The name comes from the Greek strepto- meaning twisted + kokkos meaning berry, and that is exactly what Strep look like under the microscope, like a twisted bunch of little round berries. (In technical terms, these are gram-positive, facultative anaerobic cocci). Illness caused by strep includes strep throat, strep pneumonia, scarlet fever, rheumatic fever (and rheumatic heart valve damage) and > glomerulonephritis.

Stricture, esophagus, acute: A narrowing or closure of the normal opening of the swallowing tube leading to the stomach, usually caused by scarring from acid irritation. Acute, complete obstruction of the esophagus occurs when food (usually meat) is lodged in the esophageal stricture. Patients experience chest pain, and are unable to swallow saliva. Attempts to relieve the obstruction by inducing vomiting at home are usually unsuccessful. Patients with complete esophageal obstruction can breathe, and are not at any risk of suffocation. Endoscopy is usually employed to retrieve the meat and relieve the obstruction.

Stricture of the esophagus, chronic: A narrowing or closure of the normal opening of the swallowing tube leading to the stomach, usually caused by scarring from acid irritation. A common complication of chronic gastroesophageal reflux disease (GERD). Several procedures are available for stretching (dilating) the strictures without having to resort to surgery. One of the procedures involves placing a deflated balloon across the stricture at the time of endoscopy. The balloon is then inflated, thereby opening the narrowingcaused by the stricture. Another method involves inserting tapered dilators of different sizes through the mouth into the esophagus to dilate the stricture.

STS: Sequence tagged site, a short (200 to 500 base pairs) DNA sequence that occurs but once in the human genome and whose location and base sequence are known. Detectable by polymerase chain reaction, STSs are useful for localizing and orienting the mapping and sequence data reported from many different laboratories and serve as landmarks on the developing physical map of the human genome. Expressed sequence tags (ESTs) are STSs derived from cDNAs (complementary DNAs).

Study, cross-sectional: A study done at one time, not over the course of time. A cross-sectional study a disease such as AIDS might be designed to learn its prevalence and distribution within the population at one point in time. Also known as a synchronic study.

Study, diachronic: See: Study, longitudinal.

Study, longitudinal: A study done over the passage of time. For example, a longitudinal study of children with Down syndrome (trisomy 21) might involve the study of 100 children with this condition from birth to 10 years of age. Also called a diachronic study. The opposite of a cross-sectional (synchronic) study.

Study, synchronic: See: Study, cross-sectional.

Subglottis: The lower part of the larynx; the area from just below the vocal cords down to the top of the trachea.

Sublingual gland: The smallest of the three major salivary glands. It is located. It lies under the floor of the mouth close to the midline.

Subluxation: Partial dislocation of a joint. A complete dislocation is a luxation.

Submandibular gland: The second largest of the three major salivary glands. It is located deep to the mandible (jaw bone).

Submaxillary gland: See Submandibular gland.

Subtotal hysterectomy: The uterus is sugically removed but the cervix is left is left in place. Also called a partial hysterectomy.

Succenturiate: In anatomy "succenturiate" means substituting for or accessory to an organ. For example, see Succenturiate placenta. Succenturiate placenta: An extra placenta separate from the main placenta. In anatomy "succenturiate" means substituting for or accessory to an organ. In this case, a succenturiate placenta is an accessory placenta.

Succenturiate placenta: An extra placenta separate from the main placenta. In anatomy "succenturiate" means substituting for or accessory to an organ. In this case, a succenturiate placenta is an accessory placenta.

Sudden Infant Death Syndrome (SIDS): The sudden and unexpected death of a baby with no known illness, typically affecting infants from 2 weeks to 6 months of age while sleeping. At elevated risk for SIDS are children with a brother or sister who died of SIDS; babies whose mothers smoked or used heroin, methadone, or cocaine during pregnancy; infants born weighing less than 4.4 pounds (2000 grams); children with an abnormal breathing pattern with long periods without taking a breath (apnea); .and babies who sleep on their stomachs. Since babies who sleep on their stomachs are at least 3 times more likely to die of SIDS than babies who sleep on their backs, children’s health authorities such as the American Academy of Pediatrics recommend always placing infants on their backs to sleep.

Sulcus: From the Latin for a groove, furrow, or trench. In medicine, there are many sulci (plural of sulcus) as, for example, the superior pulmonary sulcus.

Sun protection factor (SPF): A number on a scale (from 2 upwards) for rating sunscreens. Sunscreens with an SPT of 15 or higher provide the best protection from the sun's harmful rays.

Sunscreen: A substance that blocks the effect of the sun's harmful rays. Using lotions that contain sunscreens can reduce the risk of skin cancer, including melanoma.

Supernumerary: Beyond the normal number. Anything supernumerary is extra.

Supernumerary digit: An extra finger or toe.

Supernumerary nipple: An extra nipple.

Supernumerary placenta: A succenturiate or accessory placenta.

Supination: Rotation of the arm or leg outward. In the case of the arm, the palm of the hand will face forward.

Supine: Lying on the back.

Supportive care: Treatment given to prevent, control, or relieve complications and side effects and to improve the patient's comfort and quality of life.

Supraglottis: The upper part of the larynx, including the epiglottis; the area above the vocal cords.

Suprarenal gland: See adrenal gland.

Suprasternal notch: The V shaped notch at the top of the breastbone (sternum).

Surgery: An operation.

Suture: This word has several meanings depending on context. 1) A type of bone joint where two bones are held tightly together by fibrous tissue as in the skull. 2) Thread-like material used to sew tissue. 3) To stitch a wound closed.

Swimming pool granuloma: Localized nodular skin inflammation (small reddish raised areas of skin) caused by a bacterium called mycobacterium marinum. Swimming pool granuloma is typically acquired by occupational or recreational exposure to salt or fresh water, often resulting from minor trauma during caring for aquariums. The diagnosis is suggested by the history of exposure and confirmed by culturing tissue specimens which yield the microscopic organism, mycobacterium marinum. The infection can be treated with a variety of antibiotics, including doxycycline, minocycline, clarithromycin, rifampin, and trimethoprim-sulfamethoxazole. Also called "fish bowl granuloma."

Sympathetic nervous system: A part of nervous system that serves to accelerate the heart rate, constrict blood vessels, and raise blood pressure. The sympathetic nervous system, together with the parasympathetic nervous system (that slows the heart rate, increases intestinal and gland activity, and relaxes sphincter muscles), constitutes the autonomic nervous system.

Symphysiotomy: A surgical procedure to effect an immediate dramatic increase in the size of the pelvic outlet to permit delivery of a baby. The cartilage of the symphysis pubis (where the pubic bones come together) is surgically divided in the procedure which can be a life-saver for the baby.

Symphysis pubis: The Greek word "symphysis" means growing together. The "pubis" are the pubic bone. So the symphysis pubis is where the pubic bones meet (in the front of the pelvis).

Symptom: Any abnormal change in appearance, sensation, or function experienced by a patient which indicates a disease process.

Synchronic: From the Greek syn-, together + chronos, time = together in time. A synchronic study is a study done all together at one point in time rather than longitudinally over the course of time.

Syncope: Fainting represented by a partial or complete loss of consciousness.

Syndrome: A syndrome is the combination of symptoms and signs which together represent a disease process.

Syndrome, acquired immunodeficiency: AIDS.

Syndrome, antiphospholipid antibody: An immune disorder characterized by the presence of abnormal antibodies in the blood associated with certain medical conditions including abnormal blood clotting, migraine headaches, premature miscarriage, and low blood platelet counts (thrombocytopenia).

Syndrome, Barlow’s: Barlow’s syndrome is mitral valve prolapse (also known as "click murmur syndrome"), the most common heart valve abnormality, affecting 5-10% of the world population. Most patients have no symptoms and require no treatment. However, the condition can be associated with fatigue and/or palpitations. The mitral valve prolapse can often be detected by a doctor during examination of the heart and can be 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.

Syndrome, Behcet’s: Behcet’s syndrome is classically characterized as a triad of symptoms that include recurring crops of mouth ulcers (called apthous ulcers), genital ulcers, and inflammation of a specialized area around the pupil of the eye, the uvea. (The inflammation is called uveitis.) The cause of Behcet’s syndrome is not known. The disease is more frequent and severe in patients from the Eastern Mediterranean and Asia than those of European descent.

Syndrome, Bernard: A complex of abnormal findings, namely sinking in of one eyeball, ipsilateral ptosis (drooping of the upper eyelid on the same side) and miosis (constriction of the pupil of that eye) together with anhidosis (lack of sweating) and flushing of the affected side of the face. Due to paralysis of certain nerves (specifically, the cervical sympathetic nerves). Also called Horner-Bernard syndrome, Bernard-Horner syndrome and Horner’s ptosis but best known today as Horner syndrome.

Syndrome, Bloch-Sulzberger: Also known as incontinentia pigmenti (IP). A genetic disease with blisters that develop soon after birth on the trunk and limbs, then heal, but leave dark (hyperpigmented) streaks and marble-like whorls on the skin. (The name came from the erroneous idea that the skin cells were incontinent of pigment and could not contain it normally.) Other key features of IP include dental and nail abnormalities, bald patches, and (in about 1/3rd of cases) mental retardation. IP is an X-linked dominant with male lethality. The IP gene is in band q28 on the X chromosome. Mothers with IP have an equal chance of having a normal or IP daughter or a normal son. The IP sons die before birth. IP is also known as Bloch-Sulzberger syndrome.

Syndrome, Conn’s: Overproduction of the hormone aldosterone from a tumor containing tissue like that in the outer portion (cortex) of the adrenal gland. Excess aldosterone (pronounced al-do-ster-one) results in low potassium levels (hypokalemia), underacidity of the body (alkalosis), muscle weakness, excess thirst (polydipsia), excess urination (polyuria), and high blood pressure (hypertension). Also called primary aldosteronism and hyperaldosteronism. Named after the American physician Jerome W. Conn.

Syndrome, cracked tooth: A toothache caused by a broken tooth (tooth fracture) without associated cavity or advanced gum disease. Biting on the area of tooth fracture can cause severe sharp pains. These fractures are usually due to chewing or biting hard objects such as hard candies, pencils, nuts, etc. Sometimes, the fracture can be seen by painting a special dye on the cracked tooth. Treatment usually is to protect the tooth with a crown. However, if placing a crown does not relieve pain symptoms, a root canal procedure may be necessary.

Syndrome, Creutzfeldt-Jakob: Better known as Creutzfeldt-Jakob disease (CJD). A dementing disease of the brain. It is believed due to an unconventional (not a bacteria or virus), transmissible agent called a prion. Symptoms of CJD include forgetfulness, nervousness, jerky trembling hand movements, unsteady gait, muscle spasms, chronic dementia, balance disorder, and loss of facial expression. CJD is classified as a spongiform encephalopathy. Most cases occur randomly (sporadically), but inherited forms exist. There is neither treatment nor cure for CJD. Other names for CJD include Jakob-Creutzfeldt disease and spastic pseuodoparalysis.

Syndrome, Cushing’s: The constellation of symptoms and signs caused by an excess of cortisol hormone. Cushing syndrome is an extremely complex hormonal condition that involves many areas of the body. Common symptoms are thinning of the skin, weakness, weight gain, bruising, hypertension, diabetes, thin weak bones (osteoporosis), facial puffiness, and in women cessation of periods. Ironically, one of the commonest causes of Cushing’s syndrome is the administration of "cortisol-like medications" for the treatment of diverse diseases. All other cases of Cushing’s syndrome are due to excess production of cortisol by the adrenal gland including 1) an abnormal growth of the pituitary gland, which stimulates the adrenal gland, 2) a benign or malignant growth within the adrenal gland itself, which produces cortisol and 3) production within another part of the body (ectopic production) of a hormone that directly or indirectly stimulates the adrenal gland to make cortisol. Neurosurgeon Harvey Cushing (1869-1939) described hyperadrenocorticism (excessive production of cortisol by the adrenal gland) due quite specifically to an ACTH-secreting pituitary adenoma, a benign pituitary tumor that puts out ACTH (AdrenoCorticoTropic Hormone) which, in turn, drives (or overdrives) the adrenal gland to overproduce cortisol.

Syndrome, DiGeorge (DGS): This disorder is characterized by (1) low blood calcium levels (hypocalcemia) due to underdevelopment (hypoplasia) of the parathyroid glands which control calcium; (2) underdevelopment (hypoplasia) of the thymus, an organ behind the breastbone in which lymphocytes mature and multiply; and (3) defects of the heart involving the outflow tracts from the heart. Most cases of DGS are due to a microdeletion in chromosome band 22q11.2. A small number of cases have defects in other chromosomes, notably 10p13. Named after the American pediatric endocrinologist Angelo > DiGeorge. Other names for DGS include the third and fourth pharyngeal pouch syndrome and hypoplasia of the thymus and parathyroids.

Syndrome, Down: A common disorder due to a chromosome abnormality and specfically due to an extra chromosome number 21 (trisomy 21). Down syndrome includes mental retardation, a characteristic face, and multiple malformations. It is associated with a major risk for heart problems, a lesser risk of duodenal atresia (part of the intestines not developed), and a minor but still significant risk of acute leukemia. The name Down syndrome comes from the 19th century English doctor Langdon Down, a misnomer since he was curiously enough not the first person to describe the condition and, in great error, attributed the condition to a "reversion" to the mongoloid race. Hence, the old name mongolism, now considered slang.

Syndrome, dumping: A group of symptoms that occur when food or liquid enters the small intestine too rapidly. These symptoms include cramps, nausea, diarrhea, and dizziness.

Syndrome, Edwards: This is trisomy 18 syndrome. There are three instead of the normal two chromosomes #18. Children with this condition have multiple malformations and mental retardation due to the extra chromosome #18. The children characteristically have low birth weight, small head (microcephaly), small jaw (micrognathia), malformations of the heart and kidneys, clenched fists with abnormal finger positioning, and malformed feet. The mental retardation is profound with the IQ too low to even test. Nineteen out of 20 (95%) of these children die before their first birthday. The condition is named after the British physician and > geneticist John Edwards who discovered the extra chromosome in 1960.

Syndrome, fetal alcohol (FAS): The sum total of a person’s problems caused by maternal alcohol intake during pregancy.

Syndrome, fish-odor: An inborn error of metabolism associated with an offensive body odor, the smell of rotting fish, due to the excessive excretion of trimethylaminuria (TMA) in urine, sweat, and breath. Persons with TMA may experience tachycardia (fast heart rate) and severe hypertension (high blood pressure) after eating cheese (which contains tyramine) and after using nasal sprays containing epinephrine. TMA is caused by a mutation (change) in the gene for an enzyme, flavin-containing monooxygenase-3 (FMO3) encoded by a gene on chromosome #1. The FMO3 enzyme metabolizes tyramine (which is in cheese). The syndrome is associated with various psychosocial reactions, including social isolation, clinical depression and attempted suicide.

Syndrome, floppy baby: Floppy baby syndrome is a general medical reference to an abnormal condition of newborns and infants manifest by inadequate tone of the muscles. Hypotonia (inadequately toned muscles resulting in floppiness) in the newborn period and infancy can be due to a multitude of different neurologic and muscle problems.

Syndrome, fragile X: The most common heritable form of mental retardation. Fragile X syndrome is due to mutation (changes) at the fragile X site and so perforce is X-linked (carried on the X chromosome). Although it is usually more severe in males than females, the syndrome is due to a dynamic mutation (a trinucleotide repeat) that can change in length and hence in severity from generation to generation, from person to person, and even within a given person. The fragile X syndrome is also known as the Martin-Bell syndrome in honor of their discovery of it in 1943.

Syndrome, Hecht: Inherited disorder transmitted as an autosomal dominant trait in which short tight muscles make it impossible to open the mouth fully or keep the fingers straight when the hand is flexed back. The small mouth creates feeding problems. The hands may be so tightly fisted the infant crawls on the knuckles. Also called the trismus pseudocamptodactyly syndrome.

Syndrome, Horner: A complex of abnormal findings, namely sinking in of one eyeball, ipsilateral ptosis (drooping of the upper eyelid on the same side) and miosis (constriction of the pupil of that eye) together with anhidosis (lack of sweating) and flushing of the affected side of the face. Due to paralysis of certain nerves (specifically, the cervical sympathetic nerves). Also called Horner-Bernard syndrome, Bernard syndrome, Bernard-Horner syndrome and Horner’s ptosis but far and away best known as Horner syndrome.

Syndrome, Hurler: A genetic error of metabolism. There is incomplete breakdown and accumulation of a substance (a mucopolysaccharide) which is abnormally stored in the brain and other places. This usually leads to death of the individual with Hurler syndrome by their early teen years. See gargoylism.

Syndrome, incontinentia pigmenti (IP): A genetic disease with blisters that develop soon after birth on the trunk and limbs, then heal, but leave dark (hyperpigmented) streaks and marble-like whorls on the skin. (The name came from the erroneous idea that the skin cells were incontinent of pigment and could not contain it normally.) Other key features of IP include dental and nail abnormalities, bald patches, and (in about 1/3rd of cases) mental retardation. IP is an X-linked dominant with male lethality. The IP gene is in band q28 on the X chromosome. Mothers with IP have an equal chance of having a normal or IP daughter or a normal son. The IP sons die before birth. IP is also known as Bloch-Sulzberger syndrome.

Syndrome, irritable bowel (IBS): A common gastrointestinal disorder (also called spastic colitis, mucus colitis or nervous colon syndrome), IBS is an abnormal condition of gut contractions (motility) characterized by abdominal pain, bloating, mucous in stools, and irregular bowel habits with > alternating diarrhea and constipation, symtoms that tend to be chronic and wax and wane over the years. Although IBS can cause chronic recurrent discomfort, it does not lead to any serious organ problems. Diagnosis usually involves > excluding other illnesses. Treatment is directed toward relief of symptoms and includes high fiber diet, exercise, relaxation techniques, avoidance of caffeine, milk products and sweeteners, and medications.

Syndrome, joint hypermobility: See Syndrome, hypermobility.

Syndrome, Kartagener’s : The trio of sinusitis, bronchitis and situs inversus (lateral reversal of the position all organs in the chest and abdomen with the heart and stomach on the right, the liver on the left, etc.—opposite or "inverted" from their usual position).

Syndrome, kinky hair: Genetic disorder with fragile twisted ("kinky") hair and progressive deterioration of the brain. Due to an error in copper transport resulting in copper deficiency. Females are carriers and their sons with the gene have the disease. Also known as Menkes syndrome.

Syndrome, Klinefelter: The most common single cause of hypogonadism (underfunction of the gonads) and infertility in men, Klinefelter syndrome is due to a chromosome abnormality with XXY (plus additional X or Y chromosomes). It affects about 1 in 500 males and results in small testes (hypogenitalism), underproduction of testosterone and infertility (hypogonadism), and a long-limbed, long-trunked, relatively tall, slim build. Klinefelter boys tend to have learning and/or behavioral problems. At adolescence there is little growth of facial hair and a third of boys develop gynecomastia (enlargement of the male breast). Named for the physician Harry Klinefelter who with E.C. Reifenstein, Jr. and Fuller Albright (the founder of modern endocrinology) described the condition in 1942 long before its chromosomal basis became known.

Syndrome, Klippel-Feil: The combination of short neck, low hairline at the nape of the neck and limited movement of the head. It is due to a defect in the early development of the spinal column in the neck (the cervival vertebrae). The condition is also called the Klippel-Feil sequence (referring to an embryologic or early developmental sequence of events).

Syndrome, Li-Fraumeni: A family tendency to cancers due to a mutation in a gene that normally serves to curb cancer: the p53 tumor-suppressor gene. Named after Drs. Fred Li and Joe Fraumeni.

Syndrome, Lennnox: See Syndrome, Lennox-Gastaut.

Syndrome, Lennox-Gastaut: A severe form of epilepsy that usually begins in early childhood and is characterized by frequent seizures of multiple types, mental impairment, and a particular brain wave pattern (a slow spike-and-wave pattern). The seizures that are notoriously hard to treat and may lead to falls and injuries can be reduced in frequency by treatment with lamotrigone, a chemically novel antiepileptic drug. The syndrome is named for W.G. Lennox and H. Gastaut who described it.

Syndrome, Marfan: Inherited disorder with long fingers and toes, dislocation of the lens, and aortic wall weakness and aneurysm. (It has been suggested that Abraham Lincoln had Marfan syndrome.)

Syndrome, Martin-Bell: Better known as the fragile X syndrome, the most common heritable form of mental retardation. Fragile X syndrome is due to mutation (changes) at the fragile X site and so perforce is X-linked (carried on the X chromosome). Although it is usually more severe in males than females, the syndrome is due to a dynamic mutation (a trinucleotide repeat) that can change in length and hence in severity from generation to generation, from person to person, and even within a given person. The fragile X syndrome is known as the Martin-Bell syndrome in honor of their discovery of it in 1943.

Syndrome, mucocutaneous lymph node: A syndrome of unknown origin, mainly affecting young children, causing fever, reddening of the eyes > (conjunctivitis), lips and mucous membranes of the mouth, ulcerative gum disease (gingivitis), swollen glands in the neck (cervical > lymphadenopathy), and a rash that is raised and bright red (maculoerythematous) in a glove-and-sock fashion over the skin of the hands and feet which becomes hard, swollen (edematous), and peels off. Also called Kawasaki’s disease.

Syndrome, Munchhausen: Recurrent feigning of catastrophic illnesses. Named for the fictitious Baron who told tales that were whopping lies.

Syndrome, myelodysplastic: A condition in which the bone marrow does not function normally. It does not produce enough blood cells. This condition may progress and become acute leukemia. Myelodysplastic syndrome also is called preleukemia or smoldering leukemia.

Syndrome, nail-patella: Hereditary dominant condition with abnormally formed (dysplastic) or absent nails and absent or underdeveloped (hypoplastic) kneecaps (patellae). Other features include iliac horns (symmetrical bilateral central posterior iliac processes), abnormality of the elbows interfering with full range of motion (pronation and supination) and kidney disease resembling glomerulonephritis which.is often mild but can be progressive and lead to renal failure. The nail-patella gene locus found linked genetically to the ABO blood group in1965 is now known to be in chromosome region 9q34. Also called onychoosteodysplasia, Turner-Kieser syndrome, and Fong disease.

Syndrome, nervous colon: See Syndrome, irritable bowel.

Syndrome, Pallister-Killian: Condition with multiple malformations at birth and mental retardation due to isochromosome 12p mosaicism (an abnormal chromosome #12 in some cells).

Syndrome, Patau: Trisomy 13 syndrome or three chromosome number 13s instead of the normal two. Children with this condition have multiple malformations and mental retardation due to an extra chromosome #13 Named after the late Klaus Patau who described the extra chromosome in 1960. This is trisomy 13 syndrome. There are three rather than the normal two chromosomes #13. Children with this syndrome have multiple malformations and mental retardation due to the extra chromosome #13. The malformations commonly include scalp defects, hemangiomas (blood vessel malformations) of the face and nape of the neck, cleft lip and palate, malformations of the heart and abdominal organs, and flexed fingers with extra digits. The mental retardation is profound. The IQ is untestably low. The majority of trisomy 13 babies die soon after birth or in infancy. Named after the late Klaus Patau who discovered the extra chromosome in 1960.

Syndrome, Pickwickian: The combination of obesity, somnolence, hypoventilation (underbreathing), and plethoric (red) face named after the "fat and red-faced boy in a state of somnolency" in Charles Dickens’ novel The Pickwick Papers. (The same boy is thought by some to have had Prader-Willi syndrome).

Syndrome, popliteal pterygium: An inherited condition with a web behind the knee. (A pterygium is a winglike triangular membrane.)

Syndrome, Prader-Willi: A condition in children with floppiness (hypotonia), obesity, small hands and feet and mental retardation. It is due to loss of part or all of chromosome 15, specifcally the chromosome 15 from the father. The "fat and red-faced boy in a state of somnolency" described by Charles Dickens in his novel The Pickwick Papers is thought by some to have had Prader-Willi syndrome. (The same boy inspired the naming of the Pickwickian syndrome).

Syndrome premenstrual (PMS): A combination of emotional, physical, psychological, and mood disturbances that occur after ovulation and normally end with the onset of the menstrual flow.

Syndrome, Proteus: A disturbance of cell growth including benign tumors under the skin, overgrowth of the body, often more on one side than the other (hemihypertrophy), and overgrowth of fingers (macrodactyly). The syndrome is named after the Greek god Proteus the polymorphous who could change his appearance. The "elephant man" (John MerricK) of 19th century England who was thought to have had neurofibromatosis probably had Proteus syndrome.

Syndrome, radial aplasia-thrombocytopenia: See Syndrome, TAR.

Syndrome, reflex sympathetic dystrophy (RSDS): A condition that features a group of typical symptoms, including pain (often "burning" type), tenderness, and swelling of an extremity associated with varying degrees of sweating, warmth and/or coolness, flushing, discoloration, and shiny skin.

Syndrome, Reiter’s: A chronic form of inflammatory arthritis wherein the following three conditions are combined: (1) arthritis; (2) inflammation of the eyes (conjunctivitis); and (3) inflammation of the genital, urinary or gastrointestinal systems.

Syndrome, Reye’s: A sudden, sometimes fatal, disease of the brain > (encephalopathy) with degeneration of the liver, occurs in children (most cases 4-12 years of age), comes after the chickenpox (varicella) or an influenza-type illness, is also associated with taking medications containing aspirin. The child with Reye’s syndrome first tends to be unusually quiet, lethargic (stuporous), sleepy, and vomiting. In the second stage, the lethargy deepens, the child is confused, combative and delirious. And things get worse from there with decreasing consciousness, coma, seizures, and eventually death. The prognosis (outlook) depends on early diagnosis and control of the increased intracranial pressure. Reye’s syndrome is a good reason to have your child immunized against chickenpox and not give a child aspirin for fever.

Syndrome, scalded skin: See Scalded skin syndrome.

Syndrome, Shprintzen: Congenital malformation (birth defect) syndrome with cleft palate, heart defect, abnormal face, and learning problems.The condition is also called the velo-cardio-facial (VCF) syndrome. (The velum is the soft palate). Other less frequent features include short stature, small-than-normal head (microcephaly), mental retardation, minor ear anomalies, slender hands and digits, and inguinal hernia. The cause is usually a microdeletion in chromosome band 22q11.2, just as in DiGeorge syndrome. Shprintzen and DiGeorge syndromes are different clinical expressions of essentially the same chromosome defect. Syndrome, Stein-Leventhal: Known descriptively as polycystic ovarian disease (PCO), this syndrome is basically an hormonal problem that causes women to have a variety of symptoms including irregular or no periods, acne, obesity and excessive hair growth. Women with PCO are at a higher risk for uterine cancer (endometrial cancer), diabetes, high blood pressure, and heart disease. With proper treatment, risks can be minimized. The syndrome is named after the late American gynecologists Irving F. Stein, Sr. and Michael Leo Leventhal.

Syndrome, Shulman’s (Eosinophilic fasciitis): A disease which leads to inflammation and thickening of the skin and fascia. (The fascia is a lining tissue under the skin that covers a surface of underlying tissues.) When the fascia is inflamed, the condition is referred to as "fasciitis." In eosinophilic fasciitis, the involved fascia is inflamed with the eosinophil white blood cells. There is progressive thickening, and often redness and warmth, and hardness of the skin surface.

Syndrome, TAR: TAR stands for Thrombocytopenia (low blood platelets) and Aplasia (absence) of the Radius (the long bone on the thumb-side of the forearm), features characterizing this syndrome. There is phocomelia > (flipper-limb) with the thumbs always present. The fibula (the smaller bone in thye lower leg) is often absent. The risk of bleeding from too few platelets is high in early infancy but lessens with age. The condition is inherited in an autosomal recessive trait with one gene (on a non-sex chromosome) coming from each parent to the TAR child. Alternative names include > thrombocytopenia-absent radius syndrome, radial aplasia-thrombocytopenia syndrome, and tetraphocomelia-thrombocytopenia syndrome.

Syndrome, tempero-mandibular joint: Disorder of the temporo-mandibular joint(TMJ) causing pain usually in front of the ear. Pain in the TMJ can be due to trauma (such as a blow to the face), inflammatory or degenerative arthritis, or by the mandible being pushed back towards the ears whenever the patient chews or swallows. Sometimes, muscles around the TMJ used for chewing can go into spasm, causing head and neck pain and difficulty opening the mouth normally.

Syndrome, tetraphocomelia-thrombocytopenia: See Syndrome, TAR.

Syndrome, third and fourth pharyngeal pouch: See Syndrome, DiGeorge.

Syndrome, thoracic outlet: Condition due to compromise of blood vessels or nerve fibers between the armpit (axilla) and base of the neck.

Syndrome, thrombocytopenia-absent radius: See Syndrome, TAR.

Syndrome, TMJ: Disorder of the temporo-mandibular joint (TMJ) causing pain usually in front of the ear. Pain in the TMJ can be due to trauma (such as a blow to the face), inflammatory or degenerative arthritis, or by the mandible being pushed back towards the ears whenever the patient chews or swallows. Sometimes, muscles around the TMJ used for chewing can go into spasm, causing head and neck pain and difficulty opening the mouth normally.

Syndrome, toxic shock: A grave condition occurring predominantly in menstruating women using tampons, toxic shock is characterized by a highly toxic state (with sudden high fever, vomiting, diarrhea, muscle aching) followed by low blood pressure (hypotension) which can lead to shock (and death). There may be a rash resembling sunburn with peeling of skin. The Channing Laboratory in Boston under Dr. Edw. Kass discovered that toxic shock was due to a toxin produced by Staph (Staphylococcus) aureus bacteria growing under conditions with little or no oxygen. The syndrome occurs rarely in women not using tampons and in men.

Syndrome, trisomy 13: Condition with three rather than the normal two chromosomes #13. Children born with this syndrome have multiple malformations and mental retardation due to the extra chromosome #13. The congenital malformations (birth defects) commonly include scalp defects, > hemangiomas > (blood vessel malformations) of the face and nape of the neck, cleft lip > and palate, malformations of the heart and abdominal organs, and flexed fingers with extra digits. The mental retardation is profound. The IQ is untestably low. The majority of trisomy 13 babies die soon after birth or in infancy. The condition is also called Patau syndrome after the late geneticist Klaus Patau > (at the University of Wisconsin) who discovered the extra chromosome in 1960.

Syndrome, trisomy 18: There are three instead of the normal two chromosomes #18. Children with this condition have multiple malformations and mental retardation due to the extra chromosome #18. The children characteristically have low birth weight, small head (microcephaly), small jaw (micrognathia), malformations of the heart and kidneys, clenched fists with abnormal finger positioning, and malformed feet. The mental retardation is profound with the IQ too low to edven test. Nineteen out of 20 (95%) of these children die before their first birthday. The condition is also called Edwards syndrome in honor of the British physician and geneticist John Edwards who discovered the extra chromosome in 1960.

Syndrome, trisomy 21: A common chromosome disorder due to an extra chromosome number 21 (trisomy 21). The syndrome causes mental retardation, a characteristic face, and multiple malformations. It is associated with a major risk for heart problems, a lesser risk of duodenal atresia (part of the intestines not developed), and a minor but still significant risk of acute leukemia. Trisome 21 syndr0ome is also commonly called Down syndrome after the 19th century English doctor Langdon Down who was curiously enough not the first person to describe the condition, added little to knowledge and, in great error, attributed the condition to a "reversion" to the mongoloid race. The disorder was also once called mongolism, a term now considered slang.

Syndrome, Turner-Kieser: See nail-patella syndrome Turner in 1933 described two families with the disease. The name Turner is more closely associated with the XO syndrome.

Syndrome, yeast: The yeast Candida has been thought to cause a syndrome with a number of nonspecific problems including fatigue, loss of appetite, headache, short-attention span, depression and all manner of intestinal irregularities. There is no scientific evidence to support the existence of the yeast syndrome (also called the yeast connection).

Synovia: The joint fluid. The term synovia was invented in 1520 by the Swiss physician (and alchemist) Paracelsus who combined the Greek syn-(together) and oon (egg) to create a name for any body fluid that looked like the white of an egg. Today, synovia is restricted to the fluid that lubricates joints.

Synovial cyst, popliteal: A swelling in the space behind the knee (the popliteal space). The swelling is composed of a membrane-lined sac filled with synovial fluid that has escaped from the joint. Commonly called Baker’s cyst.

Synovial fluid: The slippery fluid in joints. Also called the synovia.

Synovial lining: The lining of the joint.

Synovitis: Inflammation of the synovial membrane, the lining of the joint.

Syphilis: A sexually transmitted disease (STD) that has been around for centuries and is caused by Treponema pallidum, a microscopic organism called a spirochete, a worm-like spiral-shaped organism that infects by burrowing into the moist mucous membranes of the mouth or genitals. From there, the spirochete produces the classic non-painful ulcer known as a chancre. There are three stages of syphilis. The first ("primary") stage is formation of the chancre. It 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. Even without treatment, the early infection resolves on its own in most women. However, 25% will proceed to the next stage of the disease called "secondary" syphilis, which lasts 4-6 weeks. This secondary phase can include hair loss, a sore throat, white patches in the nose, mouth, and vagina, fever, headaches, and a skin rash. There can be lesions on the genitals that look like genital warts but are caused by spirochetes rather than the wart virus. These wart-like lesions, as well as the skin rash, are highly contagious. The rash can occur on the palms of the hands and the infection can be transmitted by casual contact. The third (‘tertiary") stage of the disease involves the brain and heart and is usually no longer contagious. At this point, however, the infection can cause extensive damage to the internal organs, such as the brain, and can lead to death.

System, autonomic nervous: Part of the nervous system once thought functionally independent of the brain. The autonomic nervous system regulates key functions including the activity of the cardiac (heart) muscle, smooth muscles (e.g., of the gut), and glands. The autonomic nervous system has two divisions: (1) the sympathetic nervous system that accelerates the heart rate, constricts blood vessels, and raises blood pressure; and (2) the parasympathetic nervous system slows the heart rate, increases intestinal and gland activity, and relaxes sphincter muscles.

System, parasympathetic nervous: A part of nervous system that slows the heart rate, increases intestinal and gland activity, and relaxes sphincter muscles. The parasympathetic nervous system together with the sympathetic nervous system (that accelerates the heart rate, constricts blood vessels, and raises blood pressure) constitute the autonomic nervous system.

System, sympathetic nervous: A part of nervous system that accelerates the heart rate, constricts blood vessels, and raises blood pressure. The sympathetic nervous system together with the parasympathetic nervous system (that slows the heart rate, increases intestinal and gland activity, and relaxes sphincter muscles) constitute the autonomic nervous system.

Systemic-onset juvenile chronic arthritis: See: Systemic-onset juvenile rheumatoid arthritis (Still’s disease).

Systemic-onset juvenile rheumatoid arthritis (Still’s disease): Also known as systemic-onset juvenile chronic arthritis. Still’s disease presents with systemic (bodywide) illness including high intermittent fever, a 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 immediately apparent but, once apparent, it may persist after the systemic symptoms are gone.

Systemic therapy: Treatment that reaches cells throughout the body by traveling through the bloodstream.