Glossary B

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

B cells

A type of white blood cell involved in immunity. When stimulated by a particular antigen, B cells mature in the bone marrow into plasma cells that secrete antibodies to inactivate the antigen. Also called B lymphocytes.


A technique that uses electronic instruments to measure body functions and feed that information back to you, teaching you to bring involuntary body processes, such as blood pressure or breathing rate, under voluntary control.

Biologic response modifiers (BRMs, Biologics)

A group of medications that are derived from living sources, as opposed to synthesized chemicals, and that block specific steps in the inflammation process. Biologic response modifiers are a subset of the disease-modifying anti-rheumatic drugs (DMARDs), and likewise are used in the treatment of rheumatoid arthritis, psoriatic arthritis, psoriasis and ankylosing spondylitis. They are useful not only for easing the signs and symptoms of disease but also for slowing or stopping its progression. Current biologic response modifiers must be injected or infused, although oral versions, such as liquids, are being developed.


A test performed on a piece of tissue that is removed surgically, most often through a small incision. Depending on the piece of tissue examined, a biopsy may be used to diagnose a disease of the joint, muscle, skin or blood vessels.



A class of medications used to treat osteoporosis. Bisphosphonates inhibit bone resorption, the loss of bone through physiological means. In the body, existing bone is constantly being resorbed while new bone grows to take its place. Bone resorption is essential to healthy bones unless it outpaces the growth of new bone, resulting in osteoporosis.

Body mass index (BMI)

A measurement of a person’s body weight in relation to their height, derived by dividing weight in kilograms squared by height in meters squared. Today, the BMI is preferred to weight alone in determining obesity.

Bouchard’s nodes

Knobby growths of bone that may appear on the middle knuckles of people with osteoarthritis.


Enlargement of the joint at the base of the big toe, often due to inflammation and additional bone formation. Bunions can result from wearing tight-fitting shoes or from arthritis of the toe joint.


A small sac located between a tendon and a bone [in a joint]. The bursae (plural for bursa) reduce friction and provide lubrication.


Inflammation of a bursa caused by overuse of the joint or deformity due to arthritis. Bursitis makes movement painful because the inflammation puts pressure on the affected joint.

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