Webster's New World Medical Dictionary

bones of the skeleton
The human body has 206
bones. These consist of 80 axial (head and trunk)
bones and 126 appendicular (upper and lower
extremity) bones. See also 
bones of the arm, wrist,
and hand; bones of the head; bones of the leg,
ankle, and foot; bones of the trunk.
bones of the trunk
The 51 trunk bones consist
of 26 vertebrae, 24 ribs, and the sternum. The 26
vertebrae comprise 7 cervical, 12 thoracic, and 5
lumbar vertebrae, plus the sacrum and the coccyx.
The 24 ribs comprise 14 true ribs, 6 false ribs, and
4 floating ribs. The sternum is the breastbone. Along
with the bones of the head, also known as axial
bones.
bony syndactyly
A condition in which the bones
of the fingers or toes are joined together. Bony syn-
dactyly is not the same as cutaneous syndactyly,
which only involves webbing of the skin between the
digits.
bony tarsus
A structure that is made up of seven
bones situated between the bones of the lower leg
and the metatarsus bones of the feet. The seven
bones of the bony tarsus are the calcaneus, talus
(astragalus), cuboid, and navicular (scaphoid),
plus the first, second, and third cuneiform bones.
The bony tarsus contributes to the broad, flat frame-
work of the foot.
booster shot
An additional dose of a vaccine
needed periodically to “boost” the immune system.
For example, a booster shot of the tetanus and diph-
theria (Td) vaccine is recommended for adults
every 10 years.
borborygmus
A gurgling, rumbling, or squeak-
ing noise from the abdomen that is caused by the
movement of gas through the bowels. Also known as
stomach rumbling. The plural is borborygmi.
borderline personality disorder
A personality
type characterized by difficulty forming and keeping
stable relationships, highly emotional or aggressive
behavior, impulsivity, and rapid shifts in values, self-
image, mood, and behavior.