S

Sac       a pouch or a baglike organ.

Sacral  /sà'kræl,sak'ræl/,     referring to the sacrum.sacrum  /sà'kræm, sak'ræm/     the large, triangle-shaped bone at the top part of the pelvis. It looks like a wedge set between the two hip bones. The sacrum is shorter and wider in women than in men.-sacral, adj.matoid arthritis.

Sadism  /sà'dizæm,sad'izæm/,     1. abnormal pleasure derived from causing physical or mental pain or abuse on others; cruelty. 2. also called active algolagnia. (In psychiatry) a mental and sexual disorder marked by the wish to hurt or destroy the self-respect of another person, either a willing or unwilling partner, to get sexual satisfaction. The condition is usually long-term, is usually found in men, may be caused by concious or unconcious desires, and, in serious cases, can lead to rape, torture, and murder. Kinds of sadism are anal sadism and oral sadism. Compare 11083masochism. -sadistic, adj.

Saliva       the clear, viscous fluid secreted by glands in the mouth. Saliva contains water, mucin, organic salts, and the enzyme ptyalin that helps digest food. It keeps the mouth wet, starts to digest starches, and helps the patient to chew and swallow food.

Salivation       the secreting of saliva by the salivary glands.

Sanguineous  /sang×gwin'è×æs/     relating to blood.

Saturated       having absorbed or dissolved the largest possible amount of a given substance, and unable to absorb any more. Compare 17995unsaturated.

Scald , v. 1. burn with hot liquid or steam.  2. heat just below boiling. n.3. burn  caused by scalding

Scalp       the skin that covers the head. The face and ears are not included.

Scapula  /skap'ælæ/     one of the pair of large, flat, three-sided bones that form the back of the shoulder. Also called shoulder blade.

Scratch test       a skin test for finding an allergy, made by placing a small amount of liquid containing a suspected substance on a lightly scratched area of the skin. If a bump on the skin forms within 15 minutes, the patient is allergic to that substance.

Scorpion sting       a painful wound of a scorpion, a member of the spider family with a hollow stinger in its tail. The stings of many species are only slightly poisonous, but the sting of certain scorpions may lead to death, especially in small children. The first pain is followed within several hours by numbness, nausea, muscle spasm, shortness of breath, and convulsion. It is treated by putting ice on the wound. Severe cases require a doctor's care. An antivenin is available in some areas.

Scrofula  /skrof'yælæ/     an old name for tuberculosis of the lymph glands in the neck.

Scrotum  /skrò'tæm/     the bag of skin that holds the testicles. In older men, sick men, and in warm weather, the scrotum becomes long and floppy. The left side of the scrotum usually hangs lower than the right. See also 17056testis.-scrotal, adj.

Secrete       to release a substance into a cavity, vessel, or organ or onto the surface of the skin, as a gland.-secretion, n.

Secretin  /sikrè'tin/     a hormone made by the lining of the intestines that helps digest food. It also helps to make bile.

Secretory duct       (of a gland) a small tube that has a releasing function and joins with an excretory duct.

Sedation       a drug-caused state of quiet, calm-ness, or sleep, as by means of a sedative or sleeping pill.

Segmental fracture       a bone break in which several large pieces of bone break away from the broken bone. If the ends of these pieces come through the skin, it is called an open fracture; if they stay inside of the skin, it is called a closed fracture.

Seminiferous  /sem'inif'æræs/     carrying or releasing semen, as the tubules of the testicles.

Senile       relating to or characteristic of old age or the process of aging, especially the wasting of the mind and body that come with aging.

Senile delirium       weakness of the mind linked with very old age and marked by restlessness, insomnia, aimless wandering, and, less commonly, hallucination.

Septal defect       an abnormal defect usually present at birth in the wall separating two chambers of the heart. Kinds of septal defects are atrial septal defect and ventricular septal defect.

Septate       relating to a structure divided by a septum.

Septic abortion       an abortion that is needed when the womb becomes infected and threatens the life of the mother. It may happen by itself or it may be done by a doctor. Compare 9612infected abortion.

Septum  /sep'tæm/, pl. septa,     a dividing wall, as found separating the chambers of the heart.

Sequester       to keep apart, or away from others, as a patient sequestered to prevent the spread of an infection.

Serotonin  /ser'ætò'nin,sir'-/,     a substance found naturally in the brain and intestines. Serotonin is released from certain cells when the blood vessel walls are damaged. It acts as a strong vessel-narrowing substance. Also called 5-hydroxytryptamine.

Siamese twins       equally developed twin fetuses, produced from the same egg, that have not developed completely, resulting in their being joined together at some part of the body. With modern surgical methods, most Siamese twins can be successfully separated. See 4677conjoined twins.cervical  /sur'vikæl/     referring to the neck or a necklike structure, as the narrow lower end of the uterus (cervix).

Sieve , n., v., sieved, sieving. n.  1. meshed implement for separating coarse and fine loose matter. v. 2. sift

Silver (Ag)       a whitish precious metal used in certain medications and, blended together with other metals, to fill teeth.

Skeleton       the supporting frame for the body, it has 206 bones that protect delicate structures, provide attachments for muscles, allow body movement, serve as major reservoirs of blood, and produce red blood cells. See also 2659bone, -skeletal, adj.

Skull       the bony structure of the head, consisting of the skull (cranium) and the skeleton of the face. The cranium, which holds and protects the brain, consists of

eight bones. The skeleton of the face has 14 bones.

Smegma  /smeg'mæ/     a substance released by sebaceous glands, especially the cheesy, foul-smelling secretion often found under the foreskin of the penis and at the base of the labia minora near the glans clitoris.

Soft , adj. 1. yielding readily. 2.  gentle; pleasant. 3. not strong. 4.   free from mineral salts. 5. without alcohol.  soften, v. softly, adv.  softness, n.

Sore       1.a wound, ulcer or lesion.  2. tender or paintful.

Spasm       1. a sudden unconscious muscle tightening, as habit spasms, hiccups, stuttering, or a tic. 2. a convulsion or seizure. 3. a sudden, brief tightening of a blood vessel, bronchus, esophagus, pylorus, ureter, or other hollow organ. Compare 16415stricture.

Spasmodic dysphonia       a speech disorder in which vocalization is irregularly blocked by spasms of the voicebox. The cause is unknown. Also called spastic dysphonia.

Spatter , v., n. sprinkle in many fine drops.

Speculum  /spek'yõlæm/     a tool used to hold open a body space to make examination possible, as an ear speculum, an eye speculum, or a vaginal speculum.

Sperm    15580(semen, 16109spermatozoon).semen  /sè'mæn/     the thick, whitish fluid re-leased by the male sex organs, it carries the sperm. Also called seminal fluid, sperm.-seminal, adj.spermatozoon  /spur'mætæzò'æn,spærmat'-/, pl. spermatozoa  /-zò'æ/     the male seed, contained in semen, that fertilizes the female egg in the womb in order to create a fetus. Looking like a tadpole, it is about 50 micrograms ( inch) long and has a head, a neck, and a tail that propels it. See spermatogenesis.

Sphincter  /sfingk'tær/     a circular band of muscle fibers that narrows a passage or closes a natural opening in the body, as the outer anal sphincter, which closes the anus.

Spinal cord       a long, almost round structure found in the vertebral canal and reaching from the base of the skull to the upper part of the lower back. A major part of the central nervous system, the adult cord is about 1 cm in diameter with an average length of 42 to 45 cm and a weight of 30 g. The cord carries sense and movement signals to and from the brain and controls many reflexes. Also called chorda spinalis, medulla spinalis.

Spindle        any one of the special sensing organs found throughout the body. These spindles detect the degree of stretch in a muscle or at the meeting of a muscle with its tendon and are needed to maintain muscle tone.

Spine       the vertebral column, or backbone.

splanchnic engorgement       the overfilling or pooling of blood within the blood vessels of the stomach cavity following the removal of pressure from the stomach area, as in the removal of a large tumor, birth of a child, or drainage of a large amount of urine from the bladder.

Spleen       a soft, vessel-filled, egg-shaped organ found between the stomach and the diaphragm on the left half of the body. It contains lymphatic nodules. It has a dark purple color and varies in shape in different individuals and within the same individual at different times. The exact function of the spleen is not known, but the most recent research shows that it helps keep the blood healthy. The size of the spleen becomes larger during and after digestion and often during illness. It can weigh as much as 9 kg in a victim of malarial fever.

Splint       1. a device for holding in place any part of the body. It may be stiff (of metal, plaster, or wood) or flexible (of felt or leather). 2. (in dentistry) a device for anchoring the teeth or changing the bite. Compare 2706brace, 3347cast.

Splinter fracture       a crushing break resulting in thin, sharp bone chips.

Stenosis  /stinò'sis/     an abnormal condition marked by the tightening or narrowing of an opening or passageway in a body structure. Kinds of stenosis include aortic stenosis and pyloric stenosis.-stenotic, adj.

Sterile  /ster'il/     1. barren; unable to produce children because of a physical abnormality, often the lack of sperm in a man or blockage of the fallopian tubes in a woman. Compare 9497impotence. 2. aseptic.-sterility, n

Sternoclavicular articulation       the double joint between the breastbone (sternum) and the collar bone (clavicle). It is at the center and top of the rib cage.

Sternum       the long, flat bone in the middle of the front of the rib cage. It is sometimes called the breastbone. The sternum is longer in men than in women.i

Stimulant       any substance that speeds up a body system.

Stimulus  pl. stimuli,     anything that excites an organism or part to function, become active, or respond.-stimulate, v

Stout , adj. 1. solidly built; fat. 2.  bold or strong. 3. firm. n. 4. dark, sweet  ale. stoutly, adv. stoutness, n.

Strangulation       the tightening or closing of a tubular structure of the body, as the throat, a section of bowel, or the blood vessels of a limb, that prevents function or slows circulation. See also 9892intestinal strangulation.-strangulate, v., strangulated, adj.

Stria  /strí'æ/, pl.striae,     a streak or a narrow furrow in the skin that often results from a stretching of the skin, as seen on the stomach after pregnancy. Purplish striae are one of the classic findings in hyperadrenocorticism. Also called stretch mark.

Stricture       an abnormal short-term or permanent narrowing of the tube of a hollow organ, as the throat, pylorus of the stomach, ureter, or urethra, because of inflammation, pressure from outside the body, or scarring. Treatment varies depending on the cause. Compare 16064spasm.

Stupor       a state, marked by a lack of energy and an uncaring attitude, in which a person seems unaware of the surroundings. The condition occurs in nerve and mental disorders. Kinds of stupor are anergic stupor, benign stupor, delusion stupor, and epileptic stupor.

Subacute       of or relating to a disease or other abnormal condition present in a patient who appears to be well. The condition may be identified or discovered by means of a laboratory test or by x-ray test.

Subcutaneous  /sub'kyötà'nè×æs/     beneath the skin.

Subinvolution       a condition that occurs when the womb does not return to normal after the birth of a child. It is marked by longer and heavier bleeding after childbirth and, on pelvic examination, a larger and softer uterus than would be expected at that time. Treatment includes ergonovine given by mouth for 2 or 3 days, and, if an infection is present, an antibiotic. The blood is also tested, and iron is given if necessary. A follow-up examination is performed 2 weeks later

Suffocative goiter       an enlargement of the thyroid gland causing a feeling of suffocation on pressure.

Superfecundation       the fertilization of two or more eggs released during one menstrual cycle by sperm from the same or different males during separate acts of sexual intercourse

Superficial       1. of or relating to the skin or another surface. 2. not grave or dangerous.

Suppurate  /sup'yæràt/     to make pus.-suppuration, n., suppurative  /sup'yærà'tiv/ adj.

Sutura  /sötõr'æ/pl. suturae,     an immovable, fiberlike joint in which certain bones of the skull are connected by a thin layer of tissue. Compare 8256gomphosis, syndesmosis.

Swab       a stick or clamp for holding absorbent gauze or cotton, used for washing, cleansing, or drying a body surface, for collecting a specimen for laboratory tests, or for applying a topical medication.

Symmetric       (of the body or parts of the body) equal in size or shape; very similar in placement about an axis. Also symmetrical. Compare asymmetric.-symmetry, n.

Sympathomimetic  /sim'pæthòmimet'ik/     a drug that causes effects that look like those caused by the sympathetic nervous system. Various sympathomimetic drugs are used as decongestants of the mucous membranes of the nose and eyes. It is also used to treat asthma and other lung diseases and to treat low blood pressure and shock. Side effects may be nervousness, severe headache, anxiety, vertigo, nausea, vomiting, widened pupils, and certain urine disorders. Also called adrenergic.

Symphysis  /sim'fæsis/, pl. symphyses /-èz/,     1. also called fibrocartilaginous joint; a joint made of cartilage in which bony surfaces lying next to one another are firmly united by fiber-like cartilage. 2. pubic symphysis.-symphysic, adj.

Synergistic agent       a substance that assists or adds to the activity of another substance or agent.

Syncope  /sing'kæpè/     a fainting spell. It usually follows a feeling of lightheadedness and may often be prevented by lying down or by sitting with the head between the knees. It may be caused by many different factors, including emotional stress, pooling of blood in the legs, heavy sweating, or sudden change in room temperature or body position.

Syndrome       a group of signs and symptoms that occur together and are typical of a particular disorder or disease. See also specific syndromes

Syphilis       a sexually carried disease caused by a type of bacteria (Treponema pallidum), marked by three clear stages over a period of years. Any organ system may become involved. The bacteria are able to pass into a fetus in the womb, causing syphilis in the newborn at birth. The first stage (primary syphilis) is marked by the appearance of a small, painless, red pus-forming bump on the skin or mucous membrane between 10 and 90 days after exposure. The sore may appear anywhere on the body where contact with a sore on an infected person has occurred, but is seen most often in the pelvic region. It quickly wears away, forming a painless, bloodless ulcer, called a chancre, releasing a fluid that swarms with bacteria. The chancre may not be noticed by the patient, and many people may become infected. It heals by itself within 10 to 40 days, often creating the mistaken impression that the sore was not a serious event. The second stage (secondary syphilis) occurs about 2 months later, after the bacteria have increased in number and spread throughout the body. This stage is marked by general malaise, loss of appetite, nausea, fever, headache, hair loss, bone and joint pain, or the appearance of a rash that does not itch, flat white sores in the mouth and throat, or pimples on the moist areas of the skin. The disease remains highly contagious at this stage and can be spread by kissing. The symptoms usually continue for from 3 weeks to 3 months but may recur over 2 years. The third stage (tertiary syphilis) may not develop for 3 to 15 or more years. It is marked by the appearance of soft, rubbery tumors, called gummas, that fester and heal by scarring. Gummas may develop anywhere on the surface of the body and in the eye, liver, lungs, stomach, or sexual organs. Tertiary syphilis may be painless, unnoticed except for gummas, or it may be accompanied by deep, burrowing pain. The ulceration of the gummas may result in punched-out areas of the palate, nasal septum, or larynx. Various tissues and structures of the body, including the central nervous system, and the wall and the valves of the heart may be damaged or destroyed, leading to mental or physical disorders and premature death. Congenital syphilis resulting from infection in the womb may result in the birth of a deformed or blind infant. In some cases, the infant appears to be well until, at several weeks of age, snuffles, sometimes with a bloodstained discharge, and skin sores are observed, particularly on the palms and soles or in the genital region. Such children may also have visual or hearing defects, and early old age (progeria) and poor health may develop. Syphilis is sometimes detected from blood tests, but often the only evidence is the patient's report that he or she has been exposed. The disease may be treated with antibiotics in the first and second stages. It is also very important to tell the doctor about any sexual partners who have been exposed to syphilis so that they can be treated. In many states, active cases of syphilis must, by law, be reported to the Department of Health.

Syphilitic aortitis       a swelling condition of the aorta, occurring in tertiary syphilis and marked by widespread widening with gray, wheal-like plaques containing calcium on the inner coat and scars and wrinkles on the outer coat. There may be damage to the valves, narrowing of the mouths of the arteries, and the formation of blood clots. Cerebral embolism may result. Signs of syphilitic aortitis are pain in the middle of the chest, shortness of breath, bounding pulse, and high blood pressure. Penicillin may slow the disease, but it cannot heal the damage to the vessels and the heart. Also called Döhle-Heller disease, Heller-Döhle disease, luetic aortitis.serum  /sir'æm/     1. also called blood serum. any thin, watery fluid, especially one that keeps serous membranes wet. 2. any clear, watery fluid that has been separated from its more solid elements, as the exudate from a blister. 3. the clear, thin, and sticky liquid part of the blood that remains after clotting. 4. a vaccine made from the serum of a patient who has had some disease and used to protect another patient against that same infection or poison.