Webster's New World Medical Dictionary

mumps immunization
A vaccination for
mumps. Mumps immunization may be given indi-
vidually, or together with the measles and rubella
vaccines, in the MMR immunization, or with the
MMR vaccine modified to include a vaccine against
varicella (MMRV). See also 
MMR; MMRV.
mumps in pregnancy
Mumps contracted in
pregnancy, which can cause early miscarriage or
birth defects. The most common birth defect asso-
ciated with mumps is congenital deafness. Mumps
vaccination is not recommended during or shortly
before pregnancy because it is a live attenuated vac-
cine, so carries a risk of causing mumps infection.
Munchhausen by proxy
A form of Munchhausen
syndrome in which a parent feigns illness in a child.
In some cases the parent is simply overanxious or
poorly informed. In others, a misdirected desire for
attention or psychiatric illness is the cause. In a very
few cases, the parent actually causes the child’s ill-
ness, as by injecting toxic substances. See also
Munchhausen syndrome.
Munchhausen syndrome
Recurrent feigning of
catastrophic illnesses. Some patients with
Munchhausen syndrome actually cause their own
illness, as by secretly drinking or injecting sub-
stances. Munchhausen syndrome may be caused by
a misdirected desire for attention, although in some
cases it arises in actual psychiatric illness. It is
named for the fictitious Baron Munchhausen, who
told tall tales. See also 
body dysmorphic disorder;
hypochondria; Munchhausen by proxy.
murine typhus
See 
typhus, murine.
murmur, heart
See 
heart murmur.
muscle
The tissue of the body that functions pri-
marily as a source of power. There are three types
of muscle in the body: Muscle that is responsible for
moving extremities and external areas of the body is
called skeletal muscle, heart muscle is called car-
diac muscle, and muscle in the walls of arteries and
the bowel is called smooth muscle. See also 
cardiac
muscle; skeletal muscle; smooth muscle.