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


A therapy in which thin needles are used to puncture the body at specific sites along energy pathways called meridians. Although still widely considered an alternative therapy, acupuncture is gaining acceptance in Western medicine, primarily for use in pain relief.

American College of Rheumatology (ACR)

Organization that provides a professional, educational and research forum for rheumatologists and other people involved in the field of rheumatology across the country. The ACR helps determine, through research, what symptoms and signs define the various types of rheumatic disease diagnoses, what the appropriate treatments are for those diagnoses, and they advocate for improvements in healthcare for rheumatology patients.


A type of medication used to treat pain.


A process used before surgery or other medical procedures that induces partial or complete loss of sensation. Depending on the method of administration and area of the body that needs to be numbed, analgesic may be topical (on the skin’s surface), local (in one small area of the body), regional (in one region/larger area of the body) or general (the entire body).


Ankylosing spondylitis (AS)

A form of arthritis that mainly affects the spine and sacroiliac joints (where the spine attaches to the pelvis). In severe cases, AS may cause the spine to become fused and rigid.


A class of drugs that were originally developed and used to treatment malaria but were later found to have effects on some forms of arthritis. The antimalarial drug hydroxychloroquine is commonly used in the treatment of rheumatoid arthritis and lupus.

Antinuclear antibody (ANA)

An abnormal protein directed against a cell’s nucleus (the “control center”). The presence of these autoantibodies in the body – particularly at high levels – often indicates a connective tissue disease, such as lupus.


A surgical procedure in which bones that form a joint are held in place with metal screws or plates, allowing them to fuse into a single, immovable unit. Also called fusion.


A procedure in which a damaged joint is surgically removed and replaced with a synthetic one. It is also called joint replacement surgery.


A surgical procedure in which a thin, lighted scope is inserted into the joint through a small incision or puncture site, allowing the joint’s interior to be viewed on a monitor. Through additional small incisions, tools can be inserted to do minor surgical repairs such as smoothing rough cartilage or removing cartilage fragments.


The withdrawal of fluid from the body, such as synovial fluid from the joint.

Autoimmune disease

A disease in which the immune system, naturally designed to protect the body from foreign invaders such as viruses and bacteria, instead turns against and causes damage to the body’s healthy tissues.

Avascular necrosis

A disease in which temporary or permanent loss of the blood supply to the bones causes the bone tissue to die and collapse. Avascular necrosis is a serious potential complication of corticosteroid therapy.

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