Webster's New World Medical Dictionary

arthritis in children
Arthritis in children, usu-
ally in the form of juvenile/pediatric arthritis or
rheumatoid arthritis. See also 
arthritis, systemic-
onset juvenile rheumatoid.
arthritis mutilans
An extremely severe form of
chronic rheumatoid or psoriatic arthritis character-
ized by resorption of bones and the consequent col-
lapse of soft tissue. When this affects the hands, it
can cause a phenomenon sometimes referred to as
“telescoping fingers.”
arthrocentesis
A procedure in which a sterile
needle and syringe are used to drain fluid from the
joint. This is usually done as an office procedure or
at the bedside in the hospital. For certain condi-
tions, medication is put into the joint after fluid
removal. The needle is then removed, and a band-
age or dressing is applied over the entry point. Joint
fluid can be examined to determine the cause of the
joint swelling, such as infection, gout, or rheuma-
toid disease. Arthrocentesis can be helpful in reliev-
ing joint swelling and pain. Also known as joint
aspiration.
arthrogryposis
Joint contractures that develop
before birth and are evident at birth. With arthro-
gryposis there is a lack of the normal range of
motion in one or more joints. In normal embryonic
development, joints can be seen moving by 8 weeks
of gestation. This motion of joints is essential to the
proper development of the joints and structures
around them. Limitation of joint motion before birth
leads to joint contractures and arthrogryposis.
Prenatal limitation of joint mobility can result from
neurologic deficits, muscle defects, connective tis-
sue defects, and fetal crowding (in which there is
not enough room for the fetus to move around
freely in the womb).
arthropathy
Joint disease.
arthroscope
A thin, flexible fiberoptic scope that
is introduced into a joint space through a small inci-
sion in order to carry out diagnostic and treatment
procedures within the joint. An arthroscope is fitted
with a miniature camera, a light source, and preci-
sion tools at the end of flexible tubes. See also
arthroscopy.