Glossary R

Browse the glossary by selecting a letter or by entering an arthritis-related term:

Raynaud’s disease

A condition in which the blood vessels in the fingers and toes spasm in response to stress or cold temperatures, resulting in pain, tingling and numbness. It can occur on its own or in conjunction with another condition, such as lupus or scleroderma.

Range of motion

The distance and angles at which joints can be moved, extended and rotated in various directions. Range-of-motion exercises put joints through the various planes of movement, which helps improve mobility and function.

Reactive arthritis

A chronic form of arthritis that often occurs following an infection of the genital, urinary or gastrointestinal system. Features of reactive arthritis include inflammation of the joints, eyes and structures within the gastrointestinal or genitourinary tracts, such as intestines, kidneys or bladder.


A period when disease symptoms improve or disappear completely. Sometimes remission of rheumatic diseases, such as rheumatoid arthritis, is permanent. More often, however, it is punctuated by flares the disease.


Restless legs syndrome

A condition in which legs feel uncomfortable and may have a crawling sensation while you are sitting or lying down. Getting up and walking may bring temporary relief, but the symptoms usually return when you lie back down. Although anyone can have restless legs syndrome, it is more common among people with osteoarthritis, rheumatoid arthritis or fibromyalgia.

Rheumatic diseases

Diseases that affect the joints and soft tissues. They can cause pain and, in some cases, inflammation, tissue damage and disability.


A term used loosely (thought not as widely used as it was in the past) to refer to conditions that cause pain and swelling in the joints and supporting tissues.

Rheumatoid arthritis

An autoimmune disease that causes inflammation (with pain, stiffness, swelling) – and if not controlled, can lead to joint deformity. Most commonly, the smaller joints of the body are affected, such as those of hands and feet, wrists, elbows, knees and ankles. Inflammation associated with rheumatoid arthritis may also affect internal organs.

Rheumatoid factor

An autoantibody that is present in the majority of people with rheumatoid arthritis.


A doctor who specializes in diagnosing and treating arthritis and related diseases. To become a rheumatologist, a person must graduate from four years of college with an undergraduate degree; graduate from four years of medical school, at which point he or she is a doctor; spend two years beyond medical school as an intern, two years in an internal medicine residency and then an additional three years of clinical training in a rheumatology fellowship. Rheumatologists may also do research, teach or work in business fields.

Rotator cuff

A group of four muscles and the tendons associated with them, that arise from the scapula (shoulder blade) and connect to the head of the humerus (upper arm bone) to form a cuff that supports the shoulder joint and enables the arm to move.

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