Webster's New World Medical Dictionary

postulates, Koch
See 
Koch postulates.
postural
Pertaining to the posture or position of
the body, the attitude or carriage of the body as a
whole, or the position of the limbs (the arms and
legs). See also 
hypotension, orthostatic.
postural hypotension
See 
hypotension,
orthostatic.
potassium
The major positive ion (cation) found
inside cells. The chemical notation for potassium is
K+. The proper level of potassium is essential for
normal cell function. An abnormal increase in potas-
sium (hyperkalemia) or decrease in potassium
(hypokalemia) can profoundly affect the nervous
system and heart, and when extreme, can be fatal.
The normal blood potassium level is 3.5–5.0
milliEquivalents/liter (mEq/L), or 3.5 international
units.
Pott’s disease
See 
tuberculous diskitis.
pouch of Douglas
An extension of the peritoneal
cavity between the rectum and the back wall of the
uterus. Also known as the rectouterine pouch.
pouch, rectouterine
See 
pouch of Douglas.
pound
A measure of weight that is equal to 16
ounces or, metrically, 453.6 grams. Abbreviated lb.
power of attorney, durable
See 
durable power
of attorney.
PPMA
Postpolio muscular atrophy.
PPS
Postpolio syndrome.
Prader
-
Willi syndrome
An uncommon genetic
syndrome that is characterized by severe hypotonia
(floppiness), poor sucking and feeding problems in
early infancy, and, later in infancy, excessive eating
that, if unchecked, leads gradually to marked obe-
sity. Abbreviated PWS. Other sypmtoms include
developmental delay, mild to moderate mental retar-
dation with multiple learning disabilities, and small
gonads. The basic cause of PWS is due to absence of
the paternally contributed region 11–13 on the long
arm of chromosome 15. The child can have two
copies of chromosome region 15q11–15q13, but if
both are from the mother (a phenomenon called
maternal disomy), the child still has PWS because of