Medical Dictionary Definitions A-Z List
Medical Dictionary Definitions A - Z - «B»:
Bicuspid valve: One of the four
valves of the heart, this valve is situated between the
left atrium and the left ventricle. It permits blood to
flow one way only, from the left atrium into the left
ventricle This valve is more commonly called the mitral
valve because it has two flaps (cusps)...
Bicycle helmet: A well-known but often neglected device designed to protect the head of a bicyclist.
Helmets decrease the risk of head injuries (traumatic brain damage) by about 85%. However, only about 18% of bicyclists in the US use helmets all or most of the time. Universal helmet use could preve...
Biermer's anemia: A blood
disorder caused by a lack of vitamin B12. Patients who
have this disorder do not produce the substance in the
stomach that allows the body to absorb vitamin B12. This
substance is called intrinsic factor (IF).
Biermer's anemia, better known as pernicious anemia (PA), i...
Bietti crystalline dystrophy
Bietti crystalline dystrophy: A genetic eye disease that leads to progressive night blindness and visual field constriction and is characterized by the formation of crystals in the cornea (the clear covering of the eye), yellow shiny deposits on the retina, and progressive atrophy of the retina and ...
Bifid: Cleft (split) in two. See, for example, bifid
Bifid uvula: The uvula, the little V-shaped fleshy mass
hanging from the back of the soft palate, is cleft or split. Cleft uvula is a common minor
anomaly occurring in about 1% of whites and 10% of Native Americans. Persons with a cleft
uvula should not have their adenoids removed because, without t...
Big bone disease
Big bone disease: See: Kashin-Beck disease....
Big toe sign
Big toe sign: An important neurologic examination based
upon what the big toe (and other toes) do when the sole of the foot
is stimulated. If the big toe goes up, that may mean trouble.
The big toe response, also called the Babinski reflex, is obtained
by stimulating the external portion (the out...
BIID: Body integrity identity disorder....
Bilateral: Having, or relating to, two sides. Bilateral is as opposed, for example, to unilateral (which means
having, or relating to, one side)....
Bilateral pneumonia: See: Pneumonia, bilateral....
Bile: Bile is a yellow-green fluid that is made by
the liver, stored in the gallbladder and passes through the common
bile duct into the duodenum where it helps digest fat. The principal
components of bile are cholesterol, bile salts, and the pigment
An imbalance between these compon...
Bile acid: An acid made by the liver that works with bile to break down fats.
On a more technical level, bile acids are steroid carboxylic acids derived from cholesterol. The primary bile acids are cholic and chenodeoxycholic acids. They are conjugated with glycine or taurine before they are secret...
Bile acid resin
Bile acid resin: Bile acid resins are substances that
bind in the intestines with bile acids that contain cholesterol and
are then eliminated in the stool. The major effect of bile acid
resins is to lower LDL-cholesterol by about 10 to 20 percent. Small
doses of resins can produce useful reduc...
Bile duct cancer
Bile duct cancer: An uncommon type of cancer that arises from the bile duct, the tube that connects the liver and the gallbladder to the small intestine.
The part of the bile duct that is outside the liver is called the extrahepatic bile duct. Bile, a fluid made by the liver that breaks down fats ...