Webster's New World Medical Dictionary

ball-and-socket joint
A joint in which the
round end of a bone fits into the cavity of another
bone. The hip joint is a ball-and-socket joint.
balloon angioplasty
Coronary angioplasty that
is accomplished by using a balloon-tipped catheter
inserted through an artery in the groin or arm, to
enlarge a narrowing in a coronary artery. Angioplasty
is commonly successful in opening coronary arter-
ies. Recurrent narrowing at the site of balloon infla-
tion can still develop following successful coronary
angioplasty. See also 
coronary artery disease.
balloon tamponade
A procedure in which a
balloon is inflated within the esophagus or stomach,
to apply pressure on bleeding blood vessels, com-
press the vessels, and stop the bleeding. It is used in
the treatment of bleeding veins in the esophagus
(esophageal varices) and stomach. Also known as
esophagogastric tamponade.
banding of chromosomes
Treatment staining of
chromosomes to reveal characteristic patterns of
horizontal bands. Thanks to these banding patterns,
which resemble bar codes, each human chromo-
some is distinctive and can be identified without
ambiguity. Banding also permits the detection of
chromosome deletions (lost segments), duplications
(extra segments), and other structural abnormalities.
barbiturate
A class of drugs that depresses activ-
ity in the brain and spinal cord (central nervous sys-
tem), including many sleeping pills, sedatives,
antispasmodics, and anesthetics. Barbiturates are
addictive, carry a high risk of overdose, and should
never be used with alcohol or with other nervous
system depressants.
bariatric surgery
Surgery on the stomach
and/or intestines to help a person with extreme obe-
sity lose weight. Bariatric surgery is an option for
people who have a body mass index (BMI) above
40. It is also an option for people with a BMI
between 35 and 40 who have health problems like
type 2 diabetes or heart disease. Types of bariatric
surgery include gastric banding and gastric bypass.
See also 
bariatrics.