Glossary of Medical Terms

The use of drugs, devices, or surgery to prevent pregnancy. There are many different types of contraception. These include barrier methods to keep sperm from fertilizing the egg, hormone methods, intrauterine devices (IUDs), and surgery to close the fallopian tubes in women or close off the two tubes that carry sperm out of the testicles in men. Also called birth control.

A company hired by another company or research center to take over certain parts of running a clinical trial. The company may design, manage, and monitor the trial, and analyze the results. Also called CRO.

A permanent tightening of the muscles, tendons, skin, and nearby tissues that causes the joints to shorten and become very stiff. This prevents normal movement of a joint or other body part. Contractures may be caused by injury, scarring, and nerve damage, or by not using the muscles. It may also occur at some point in time after a stem cell transplant that caused chronic graft-versus-host disease.

Anything (including a symptom or medical condition) that is a reason for a person to not receive a particular treatment or procedure because it may be harmful. For example, having a bleeding disorder is a contraindication for taking aspirin because treatment with aspirin may cause excess bleeding.

Having to do with the opposite side of the body.

A series of x-ray pictures of the esophagus taken after a patient drinks a liquid containing barium sulfate (a form of the silver-white metallic element barium). The barium sulfate coats and outlines the inner wall of the esophagus so that it can be seen on the x-ray pictures. Also called esophagram.

A dye or other substance that helps show abnormal areas inside the body. It is given by injection into a vein, by enema, or by mouth. Contrast material may be used with x-rays, CT scans, MRI, or other imaging tests.

An animal in a study that does not receive the treatment being tested. Comparing the health of control animals with the health of treated animals allows researchers to evaluate the effects of a treatment more accurately.

In a clinical trial, the group that does not receive the new treatment being studied. This group is compared to the group that receives the new treatment, to see if the new treatment works.

A clinical study that includes a comparison (control) group. The comparison group receives a placebo, another treatment, or no treatment at all.