Glossary

Find definitions for thousands of medical terms, treatments, and tests -- even health-related abbreviations, prefixes, and suffixes.

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The United States Preventive Services Task Force is this country's leading source of recommendations and guidelines for screening tests, counseling, and use of medicines for disease prevention. It is composed of medical experts and is sponsored by the Department of Health and Human Services Agency for Healthcare Research and Quality (AHRQ).

The task force regularly conducts rigorous, impartial assessments of scientific evidence and develops recommendations for clinical preventive services.

Last Revised: June 5, 2012

Author: Healthwise Staff

Medical Review: John Pope, MD - Pediatrics & R. Steven Tharratt, MD, MPVM, FACP, FCCP - Pulmonology, Critical Care Medicine, Medical Toxicology

An ulcer is a sore that develops on the skin (such as the skin around the ankles) or a mucous membrane (such as inside the mouth, stomach, or intestines). Ulcers can be shallow or deep and can destroy the skin or the membrane where they develop.

Ulcers can be caused by some types of infection, injury, or cancer.

Last Revised: December 27, 2012

Author: Healthwise Staff

Medical Review: William H. Blahd, Jr., MD, FACEP - Emergency Medicine & H. Michael O'Connor, MD - Emergency Medicine

Ultrasound is a test that uses reflected sound waves to produce an image of organs and other structures in the body. It does not use X-rays or other types of possibly harmful radiation.

For ultrasound testing, gel or oil is applied to the skin to help transmit the sound waves. A small, handheld instrument called a transducer is passed back and forth over the area of the body that is being examined. The transducer sends out high-pitched sound waves (above the range of human hearing) that are reflected back to the transducer. A computer analyzes the reflected sound waves and converts them into a picture that is displayed on a TV screen. The picture produced by ultrasound is called a sonogram, echogram, or ultrasound scan. Pictures or videos of the ultrasound images may be made for a permanent record.

Ultrasound is most useful for looking at organs and structures that are either uniform and solid (such as the liver) or fluid-filled (such as the gallbladder). Mineralized structures (such as bones) or air-filled organs (such as the lungs) do not show up well on a sonogram.

Last Revised: November 29, 2012

Author: Healthwise Staff

Medical Review: Kathleen Romito, MD - Family Medicine & Howard Schaff, MD - Diagnostic Radiology

Ultrasound is high-pitched sound that people cannot hear. These high-pitched sound waves are sometimes used to treat muscle spasms and pain and to promote healing.

Ultrasound at higher intensities creates a deep heat that may help to ease muscle spasms, relax and warm muscles, and increase muscle elasticity before stretching and exercise.

Ultrasound may also act on the cells to promote healing. At lower intensities, ultrasound can have this healing effect without also heating the tissues.

Excessive use of either the heating or non-heating properties of ultrasound can damage tissues. Ultrasound is not generally used for children.

Last Revised: March 4, 2011

Author: Healthwise Staff

Medical Review: Adam Husney, MD - Family Medicine & David A. Fleckenstein, MPT - Physical Therapy

The umbilical cord is the ropey structure that connects the fetus to the placenta in the mother's uterus. Blood vessels in the cord bring nourishment to the fetus and take away waste products.

The umbilical cord is formed in the fifth week of pregnancy.

When the baby is born, the umbilical cord is about 2 ft (0.6 m) long.

Last Revised: January 10, 2013

Author: Healthwise Staff

Medical Review: Susan C. Kim, MD - Pediatrics & John Pope, MD - Pediatrics

Body mass index (BMI), which measures weight in relation to height, is used to identify a possible weight problem for a child. A child with a BMI in the 86th to 94th percentile on a growth chart is usually considered overweight.

In some cases, a child may be overweight because he or she has a large amount of body fat (adipose tissue). But not all children with BMIs in the 86th to 94th percentile have too much body fat. For instance:

  • A child who has grown consistently at a higher percentile for most of his or her life may just be bigger than other children of the same age due to genetics.
  • Before and during puberty, it is normal for children to have a significant gain in weight before beginning to grow in height. This can temporarily increase a child's BMI.
  • Children who are very muscular (for instance, children who are very active in sports) may have a higher BMI but have normal or even low amounts of body fat.

Last Revised: August 29, 2011

Author: Healthwise Staff

Medical Review: John Pope, MD - Pediatrics & Rhonda O'Brien, MS, RD, CDE - Certified Diabetes Educator

The results of some medical tests are reported in units per liter (U/L).

  • A unit is an arbitrary amount agreed upon by scientists and doctors.
  • A liter is a measure of volume that is slightly larger than a quart.
  • A kilo unit is one thousand units. It is written kU/L. Some medical tests are reported using this standard international unit (SI unit).

Last Revised: May 6, 2011

Author: Healthwise Staff

Medical Review: Anne C. Poinier, MD - Internal Medicine & Thomas M. Bailey, MD - Family Medicine

An unlabeled use of a drug is when a doctor prescribes a medicine for a purpose other than that for which it has been specifically designed and approved. Sometimes a drug is prescribed for a specific unlabeled use so often that doctors consider it a common practice.

In the United States, the Food and Drug Administration (FDA) approves drugs for specific uses.

Last Revised: March 9, 2012

Author: Healthwise Staff

Medical Review: E. Gregory Thompson, MD - Internal Medicine & Theresa O'Young, PharmD - Clinical Pharmacy

Unstable angina happens when blood flow to the heart is suddenly slowed by narrowed vessels or small blood clots that form in the coronary arteries. Unstable angina is a warning sign that a heart attack may soon occur.

Unstable angina is an emergency.

Unstable angina symptoms are similar to a heart attack. They may include chest pain or pressure that occurs at rest or with less and less exertion. Symptoms may become severe and last longer. And they may not respond to nitroglycerin or rest.

Unstable angina is a change from stable angina—a pattern of predictable chest pain or other symptoms. Stable angina symptoms are relieved by rest or nitroglycerin.

Last Revised: April 4, 2011

Author: Healthwise Staff

Medical Review: E. Gregory Thompson, MD - Internal Medicine & John M. Miller, MD - Electrophysiology

An upper respiratory tract infection (URI) is a bacterial or viral infection of the nose, sinuses, or throat. Common symptoms of a URI are a runny or stuffy nose and a cough.

Examples of URIs include influenza (flu), a cold, and sinusitis.

Treatment for a URI is based on whether a doctor suspects it is caused by a bacteria or virus. If the cause is a bacterial infection, antibiotics are used. If the cause is a viral infection, home treatment is used, such as getting extra rest and drinking plenty of liquids.

Frequent hand-washing, especially during cold or flu season, can help prevent URIs. People should also try to avoid using their hands to wipe their eyes, nose, or mouth. Avoiding smoking can also help.

Last Revised: July 10, 2012

Author: Healthwise Staff

Medical Review: E. Gregory Thompson, MD - Internal Medicine & Robert L. Cowie, MB, FCP(SA), MD, MSc, MFOM - Pulmonology

The ureters are small tubes, each about 10 in. (25 cm) long, that carry urine from the kidneys to the bladder.

Last Revised: May 2, 2011

Author: Healthwise Staff

Medical Review: E. Gregory Thompson, MD - Internal Medicine & Christopher G. Wood, MD, FACS - Urology, Oncology

The urethra is the tube that carries urine from the bladder to outside of the body. Urine is produced in the kidneys and flows through the ureters to the bladder, where it is stored until a person urinates.

The urethra is significantly shorter in women than in men.

Last Revised: May 16, 2011

Author: Healthwise Staff

Medical Review: E. Gregory Thompson, MD - Internal Medicine & Avery L. Seifert, MD - Urology

Urinary incontinence means not being able to control the release of urine. Sometimes it's caused by a temporary problem, like a urinary infection, and goes away when the infection is treated. In other cases, it's caused by changes in the muscles or nerves around the bladder and the problem is an ongoing one. Treatment includes exercises, medicines, and sometimes surgery.

Last Revised: October 9, 2012

Author: Healthwise Staff

Medical Review: E. Gregory Thompson, MD - Internal Medicine & Avery L. Seifert, MD - Urology

A urinary tract infection is a general term for an infection anywhere between the kidneys and the urethra (where urine comes out). Most urinary tract infections are bladder infections. They often cause pain or burning when you urinate. They're caused by bacteria and can be cured with antibiotics.

Last Revised: October 9, 2012

Author: Healthwise Staff

Medical Review: E. Gregory Thompson, MD - Internal Medicine & Avery L. Seifert, MD - Urology

Urologists are medical doctors who specialize in the diagnosis and treatment of diseases of the urinary system in men and women and disorders of the male reproductive system.

Urologists can prescribe medicines, perform surgery, and treat urination problems, such as problems holding urine (incontinence) and tumors or stones in the urinary system. They treat problems of the male reproductive system, such as impotence (erectile dysfunction). Urogynecologists specialize in treating urinary problems involving the female reproductive system. And pediatric urologists specialize in diagnosing and treating urinary problems in children.

Urologists can be board-certified through the American Board of Urology, which is recognized by the American Board of Medical Specialties.

Last Revised: August 17, 2012

Author: Healthwise Staff

Medical Review: Anne C. Poinier, MD - Internal Medicine & E. Gregory Thompson, MD - Internal Medicine