Webster's New World Medical Dictionary

pericardium, parietal
The tough, thickened
outer layer of the pericardium. The parietal peri-
cardium loosely cloaks the heart and is attached to
the central part of the diaphragm and the back of
the breastbone.
pericardium, visceral
The double inner layer of
the pericardium. One layer of the visceral peri-
cardium closely adheres to the heart, and the other
lines the inner surface of the outer (parietal) peri-
cardium. The intervening space is filled with peri-
cardial fluid. Also known as epicardium.
pericentric chromosome inversion
See 
chro-
mosome inversion, pericentric.
perichondrial
Having to do with the perichon-
drium, the membrane that surrounds cartilage.
perichondritis
Inflammation of the perichon-
drium.
perichondrium
A dense membrane that is com-
posed of fibrous connective tissue that closely wraps
all cartilage except the cartilage in joints, which is
covered by a synovial membrane.
perichondroma
A benign tumor that arises from
the perichondrium.
perimenopause
See 
menopause transition.
perinatal
Pertaining to the period immediately
before and after birth. The perinatal period is
defined in diverse ways. Depending on the defini-
tion, it starts at the 20th to 28th week of gestation
and ends 1 to 4 weeks after birth.
perinatal transmission
See 
vertical transmis-
sion.
perinatalogist
An obstetrical subspecialist who
is concerned with the care of the mother and fetus
when there is a higher-than-normal risk of compli-
cations. Most perinatologists are obstetricians. A
high-risk baby is often cared for by a perinatologist
before birth and by a neonatologist after birth.
perinatalogy
A subspecialty of obstetrics that
is concerned with the care of the mother and
fetus when there is a higher-than-normal risk for
complications.