Medical Glossary

Saccharides- a group of carbohydrates, including sugars and starches

Sacroiliac joints- the pair of joints located in the pelvis between the sacrum and the hipbones

Sacroiliitis- inflammation of the sacroiliac joints, which causes pain in the lower body

Sacrum- the triangular bone located at the bottom of the spine that is connected to the tailbone, the hipbones near the sacroilial joints, and the rest of the spine

SADS- see Seasonal affective disorder syndrome

Safe sex- measures taken to reduce the risk of acquiring a sexually transmitted disease, such as the use of a condom

Saline- a salt solution or any substance that contains salt

Salivary glands- a group of glands that secrete saliva into the mouth

Salmonella- a group of bacteria; includes a species that causes food poisoning and another responsible for typhoid fever

Salmonellosis- infection by salmonella bacteria

Salpingectomy- surgical removal of one or both fallopian tubes

Salpingitis- inflammation of a fallopian tube

Salpingography- X-ray examination of the fallopian tubes

Salpingolysis- removal of abnormal scar tissue between a fallopian tube and nearby tissue

Salpingo-oophorectomy- the surgical removal of one or both of the fallopian tubes and one or both of the ovaries

Salpingostomy- surgical opening of a fallopian tube for drainage or removal of an obstruction

Sarcoidosis- a rare disease with no known cause that leads to inflammation in tissues throughout the body, including the lymph nodes, lungs, liver, skin, and eyes

Sarcoma- a cancer in connective tissue, fibrous tissue, or blood vessels

Saturated fat- fats that contain the maximum amount of hydrogen possible, such as those found in meats and dairy products; can contribute to coronary heart disease and the development of some cancers

Saturday night palsy- temporary paralysis of the arm after extended pressure on a nerve in the armpit

Scabies- a highly contagious skin disorder caused by a mite that burrows into the skin and produces an intense, itchy rash

Scarlet fever- an infectious childhood disease, caused by a streptococcus bacteria, that leads to a sore throat, fever, and rash

Schistosomiasis- infestation by a parasitic blood worm that can damage the liver, bladder, and intestines

Schizophrenia- a group of mental disorders characterized by abnormal thoughts, moods, and actions; sufferers have a distorted sense of reality, and a split personality (thoughts do not logically fit together)

Schönlein-Henoch purpura- inflammation and leakage of blood vessels, causing a rash

Sciatica- pain along the sciatic nerve, which runs down the length of the leg to the foot; usually caused by pressure on the nerve due to disk prolapse or a tumor, abscess, or blood clot

Sclera- the tough, white coating that covers and protects the inner structures of the eye

Scleroderma- an immune system disorder of varying degree that can affect many areas of the body

Sclerotherapy- treatment of varicose veins by injection of a solution that destroys them

Scoliosis- a condition in which the spine curves to one side and usually curves toward the opposite side in another section to compensate, producing a characteristic

S shape Screening- the testing of an otherwise healthy person in order to diagnose disorders at an early stage

Scrotum- the sac containing the testicles

Scurvy- a disease caused by a lack of vitamin C, characterized by weakness, bleeding and pain in joints and muscles, bleeding gums, and abnormal bone and tooth growth

Seasonal affective disorder syndrome- a type of depression that seems to be linked to shorter periods of daylight during the fall and winter

Sebaceous cyst- a swelling that occurs under the skin, most commonly on the scalp, face, ears, and genitals; although usually harmless, can grow very large and become painful if infected

Seborrhea- excessive oiliness of the face and scalp

Sebum- the oily, lubricating substance that is secreted by glands in the skin

Secondary- describes a disease or disorder that follows or is caused by another one

Sedatives- a group of drugs that have a calming effect; used to treat anxiety and pain, bring on sleep, and help relax a person before surgery

Seizure- sudden uncontrolled waves of electrical activity in the brain, causing involuntary movement or loss of consciousness

Selenium- an element needed by the body only in very small amounts that helps maintain tissue elasticity

Semen- fluid released during ejaculation that contains sperm along with fluids produced by the prostate gland and the seminal vesicles

Semen analysis- a procedure in which a semen sample is examined to determine the amount of sperm present, along with their shape and ability to move; commonly used in the treatment of male infertility

Seminal vesicles- two saclike glands in men that produce part of the fluid in semen

Seminiferous tubules- coiled tubes inside of the testicle that are the site of sperm production

Seminoma- a type of testicular cancer that is made up of only a single type of cell

Senile plaques- abnormal deposits of a protein called amyloid in the brain; characteristic of Alzheimer disease

Sensorineural hearing loss- deafness caused by damage to the inner ear or the nerve that conducts signals from the ear to the brain

Sensory nerve- nerves that carry information about the body's senses toward the brain

Sensory organ- an organ that receives and relays information about the body's senses to the brain

Sepsis- the infection of a wound or tissue with bacteria, causing the spread of the bacteria into the bloodstream; now also known as systemic inflammatory response syndrome caused by a microbe

Septal defect- a birth defect in which a hole is present in the wall that separates the left and right sides of the heart

Septic arthritis- joint inflammation caused by a bacterial infection

Septicemia- a life-threatening condition in which bacteria multiply in the blood and produce toxic materials; commonly known as blood poisoning; now also known as systemic inflammatory response syndrome.

Septic shock- a life-threatening condition in which tissues become damaged and blood pressure drops due to bacteria multiplying and producing poisons in the blood

Serotonin- a chemical that transmits nerve impulses in the brain, causes blood vessels to constrict (narrow) at sites of bleeding, and stimulates smooth muscle movement in the intestines

Serum- the clear, watery fluid that separates from clotted blood Sex chromosomes- the X and Y chromosomes that determine a person's gender; women normally have two X chromosomes and men normally have one X and one Y

Sex hormones- hormones responsible for producing sex characteristics and controlling sexual functions

Sex-linked disorder- a disorder that is caused by genes located on the sex chromosomes

Sexually transmitted disease- infections that are most commonly spread through sexual intercourse or genital contact

Shigellosis- a bacterial infection of the intestines, causing abdominal pain and diarrhea

Shingles- a nerve infection caused by the chickenpox virus, causing areas of painful rash covered with blisters

Shin splints- pain and tenderness experienced in the lower leg as a result of damage or strain to leg muscles and tendons; usually caused by exercise

Shock- a reduced flow of blood throughout the body, usually caused by severe bleeding or a weak heart; without treatment, can lead to a collapse, coma, and death

Shunt- an artificially constructed or an abnormal passage connecting two usually separate structures in the body

Sickle cell anemia- a genetic disorder in which the red blood cells are abnormal and deformed, causing anemia (reduced ability to transport oxygen in the blood) and clogging of blood vessels; bouts of fever, headache, and weakness result

Sickle cell trait- a less serious form of sickle cell anemia

Sick sinus syndrome- abnormal functioning of the structure that regulates the heartbeat, causing episodes of abnormal heart rhythm

SIDS- see Sudden infant death syndrome

Sigmoidoscopy- an examination of the rectum and the lowest part of the large intestine using a flexible viewing tube inserted through the anus

Silicone- a group of compounds of silicon and oxygen; commonly used as implants in cosmetic surgery because they resist body fluids and are not rejected by the body

Silicosis- a respiratory disease caused by inhalation of dust containing the mineral silica

Single photon emission computed tomography- an imaging technique in which a radioactive substance is introduced into the body and the radiation emitted by the substance is detected by a camera and is transformed into cross-sectional images by a computer

Sinoatrial node- the structure that regulates the heartbeat; a natural "pacemaker"

Sinus- a cavity within bone or a channel that contains blood; also refers to an abnormal tract in the body

Sinus bradycardia- a regular heart rate of less than 60 beats per minute

Sinusitis- inflammation of the lining of the cavities in the bone surrounding the nose (the sinuses), usually as a result of a bacterial infection spreading from the nose

Sinus rhythm- normal heart rhythm

Sinus tachycardia- a regular heart rate of over 100 beats per minute

Sjögren's syndrome- a condition characterized by dryness of the eyes, mouth, and vagina that tends to occur along with certain disorders of the immune system

Skin graft- a method of treating damaged or lost skin in which a piece of skin is taken from another area of the body and transplanted in a damaged or missing section

Skin patch- a sticky patch attached to the surface of the skin that releases drugs into the bloodstream

Skin patch test- a diagnostic test in which different allergens are taped to the skin to determine which causes an allergic reaction

Skin prick test- a test performed to determine a person's sensitivity to a certain allergen by applying it to a small needle and using that needle to pierce the skin

Skull- the bones that form the framework of the head and enclose and protect the brain and other sensory organs

Sleep apnea- a condition in which breathing stops for very short periods of time during sleep

Sleeping sickness- an infectious disease in Africa spread by the bite of a tsetse fly that causes a fever and weakness

Slipped disk- the common term for disk prolapse

Small-cell carcinoma- the most serious form of lung cancer

Small intestine- the long tube running from the stomach to the large intestine that is involved in digestion of foods and absorption of nutrients

Smallpox- a highly contagious and often fatal viral infection that has been completely eradicated by immunization

Smear- a sample of cells spread across a glass slide to be examined through a microscope

Sodium- a mineral that plays a role in the body's water balance, heart rhythm, nerve impulses, and muscle contraction; present in table salt (sodium chloride)

Sodium bicarbonate- a substance used as an antacid

Solar plexus- the largest network of nerves in the body, located behind the stomach

Somatic- pertaining to the body

Spasm- an involuntary muscle contraction; can sometimes be powerful and painful

Spasticity- muscle stiffness caused by an increase in contractions of the muscle fibers

Spastic paralysis- spasticity involving partial paralysis

SPECT- see Single photon emission computed tomography

Speculum- an instrument that holds an opening of the body open so that an examination can be performed or a sample can be taken

Speech therapy- treatment to help someone overcome a problem communicating verbally

Sperm- the male sex cell produced in the testicles

Sperm antibody- an antibody against sperm that can be produced by a woman's immune system

Spermatocele- a harmless cyst containing fluid and sperm that occurs in the tube through which sperm travel from the testicles

Sperm count- the amount of normally functioning sperm per some unit of semen; used to determine a man's fertility

Spermicide- a contraceptive substance that kills sperm

Sphincter- a ring of muscle fibers located around a naturally occurring passage or opening in the body that opens and closes to regulate passage of substances

Sphygmomanometer- an instrument used to measure blood pressure

Spider nevus- a collection of dilated (widened) capillaries on the skin that creates a patch resembling a spider

Spina bifida- a birth defect in which a section of the baby's spine fails to develop completely, leaving the spinal cord exposed in that section

Spina bifida occulta- the least dangerous form of spina bifida, in which bones in the spine fail to close but there is no protrusion of the spinal cord or its fluid cushion out of the body

Spinal cord- a long tube of nerve tissue inside the spinal column, running from the brain down the length of the back inside of the spine

Spinal fusion- the surgical joining of two or more adjacent vertebrae using bone fragments; used to help severe back pain or prevent damage to the spinal cord

Spinal tap- another term for a lumbar puncture

Spine- the column of bones and cartilage running along the midline of the back that surrounds and protects the spinal cord and supports the head

Spiral fracture- a coiled break in a bone, resembling a corkscrew

Spirometry- a test of lung condition; a person breathes into a machine called a spirometer that measures the volume of air exhaled

Spleen- an organ located in the upper left abdomen behind the ribs that removes and destroys old red blood cells and helps fight infection

Splenectomy- surgical removal of the spleen

Splint- a device that is used to immobilize a part of the body

Splinter hemorrhage- a splinter-shaped area of bleeding under a fingernail or toenail

Spondylitis- inflammation of the joints between the bones of the spine

Spondylolisthesis- the slipping of a vertebra in the spine over the one below it

Spondylolysis- a disorder in which the lower part of the spine is weakened by an abnormally soft vertebra

Sporotrichosis- an infection with a fungus acquired through a skin wound; causes an ulcer at the site of infection and small, rounded masses of tissue near it

Sprain- the tearing or stretching of the ligaments in a joint, characterized by pain, swelling, and an inability to move the joint

Sprue- a digestive disorder in which nutrients cannot be properly absorbed from food, causing weakness and loss of weight

Sputum- mucus and other material produced by the lining of the respiratory tract; also called phlegm

Squamous cell carcinoma- a type of skin cancer arising from flat cells of the epithelium; can also affect the lungs, cervix, and esophagus

Stapedectomy- surgical removal of a stapes (a sound-conducting bone in the middle ear) that cannot move to transmit sound; performed to treat hearing loss caused by otosclerosis

Staphylococci- common bacteria that cause skin infections and a number of other disorders

Status asthmaticus- a life-threatening asthma attack requiring immediate treatment

Status epilepticus- a life-threatening succession of epileptic seizures

STD- see Sexually transmitted disease

Stein-Leventhal syndrome- see Polycystic ovary syndrome

Stem cells- cells that give rise to the different types of blood cells

Stenosis- narrowing of a body passageway

Stent- a device used to hold tissues in place, such as to support a skin graft

Stereotaxic surgery- brain surgery done through a small opening in the skull and guided by X-rays or computer-aided imaging techniques

Sterilization- a surgery performed to make a person incapable of reproducing; also refers to the process of killing microorganisms on objects such as surgical instruments

Sternum- the long, flat bone located at the center of the chest

Steroids- a group of drugs that includes corticosteroids, which resemble hormones produced by the adrenal glands, and anabolic steroids, which are similar to the hormones produced by the male sex organs

Stillbirth- a baby that is born dead after the 28th week of pregnancy; also called late fetal death

Stoma- a surgically formed opening on a body surface

Stomach bypass- a surgical procedure to treat an obstructed stomach or severe obesity in which the passage of food is diverted around the stomach and directly into the small intestine

Stomach stapling- a procedure in which the stomach is made smaller by partitioning it off using metal staples; used as an extreme treatment of severe obesity

Stool- another term for feces

Strabismus- a condition in which the eyes are not aligned correctly, such as cross-eye (one eye points inward) and walleye (one eye points outward)

Straight-leg raising- a simple test performed in a doctor's office to check for disk prolapse

Strain- muscle damage resulting from excessive stretching or forceful contraction

Strangulated hernia- a hernia in which the protruding organ or tissue loses its blood supply, requiring emergency surgery

Strawberry nevus- a bright red, raised birthmark that usually disappears without treatment

Strep throat- a throat infection caused by streptococcus bacteria; characterized by a sore throat, fever, and enlarged lymph nodes in the neck

Streptococci- bacteria that cause a variety of diseases, including pneumonia and strep throat

Stress fracture- a bone break resulting from repeated pressure on the bone

Stretch marks- lines on the skin that occur when the inner skin layer is stretched thin and loses its elasticity

Stroke- damage to part of the brain because of a lack of blood supply (due to a blockage in an artery) or the rupturing of a blood vessel; leads to complete or partial loss of function in the area of the body that is controlled by the damaged part of the brain

Stye- a pus-filled abscess in the follicle of an eyelash; caused by a bacterial infection

Subcutaneous- a medical term meaning "beneath the skin"

Submucosa- the layer of connective tissue under a mucous membrane

Suction lipectomy- see Liposuction

Sudden infant death syndrome- the unexpected, sudden death of an apparently healthy baby, the cause of which cannot be found; also called crib death

Suppository- a solid cone or bullet-shaped object made up of a chemically inactive substance and a drug that is inserted into the rectum or vagina; used to administer a drug

Suppuration- the production of pus

Surfactant- a mixture of substances secreted by the air sacs of the lungs that prevents the air sacs from collapsing during exhalation

Surrogate- a woman who agrees to become pregnant and give her baby to someone else when the child is born

Suture- a surgical stitch that helps close an incision or wound so that it can heal properly

Sweat glands- tiny structures in the skin that secrete sweat

Sweat test- a measure of the saltiness of sweat to help diagnose cystic fibrosis

Swimmer's ear- see Otitis externa

Sycosis barbae- a bacterial infection of the hair follicles in the beard area

Sympathetic nervous system- the part of the autonomic nervous system that raises blood pressure and heart rate in response to stress

Syndactyly- a condition in which fingers or toes are fused together

Syndrome- a group of symptoms that indicate a certain disorder when they occur together

Synovectomy- surgical removal of the synovial membrane

Synovial fluid- a lubricating fluid secreted by the synovial membrane

Synovial membrane- the thin membrane that lines the inside of a joint capsule

Synovitus- inflammation of the membrane lining a joint capsule as a result of injury or infection or due to a chronic illness such as rheumatoid arthritis; characterized by redness, swelling, stiffness, and pain

Syphilis- a sexually transmitted disease; initially causes only painless sores on the genitals but can be life-threatening if untreated

Systemic- affecting the whole body

Systemic inflammatory response syndrome- a condition characterized by having two of the following four clinical criteria: fever, rapid breathing, increased heart rate, and abnormal white blood cell count

Systemic lupus erythematosus- a disease of the immune system that causes inflammation of connective tissue in many areas of the body, including the skin, lungs, heart, joints, and kidneys

Systolic pressure- the blood pressure measured while the heart is contracting