psychosurgeryAny operation on the
brain that is carried out as a treatment
for serious mental illness. It is per-
formed only as a last resort. Prefrontal
lobotomyhas now been largely replaced
by types of stereotaxic surgery.
psychotherapyTreatment of mental
and emotional problems by psycho-
logical methods. Patients talk to a ther-
apist about their symptoms and
problems, with the aim of learning
about themselves, developing insights
into relationships, and changing behav-
iour patterns.
psychotropic drugsDrugs that have
an effect on the mind, including hallu-
cinogenic drugs, sedative drugs, sleeping
drugs, tranquillizer drugs, and anti-
psychotic drugs.
pterygiumA wing-shaped thickening of
the conjunctivathat extends from either
side of the eye towards the centre. Ptery-
gium is attributed to prolonged exposure
to bright sunlight and is common in
tropical areas. It is surgically removed if
it threatens vision or causes discomfort.
ptosisDrooping of the upper eyelid. The
condition may be congenital, occur
spontaneously, or be due to injury or
disease, such as myasthenia gravis. Pto-
sis is usually due to a weakness of the
levator muscle of the upper eyelid or to
interference with the nerve supply to
the muscle. Severe congenital ptosis is
corrected surgically to avoid the devel-
opment of amblyopia.
ptyalismSee salivation, excessive.
pubertyThe period when secondary
sexual characteristicsdevelop and the
sexual organs mature. Puberty usually
occurs between the ages of 10 and 15.
(See also precocious puberty.)
pubesThe pubic hair or the area of the
body covered by this hair.
pubic boneThe front part of the fused
bones that form the pelvis.
pubic liceSmall, wingless insects (PHTHI-
RUS PUBIS) that live in the pubic hair and
feed on blood. Also called crab lice or
crabs, they are usually spread by sexual
contact. A louse has a flattened body,
up to 2 mm across. Female lice lay eggs
(nits) on the hair, where they hatch
about 8 days later. On men, the lice may
also be found in hair around the anus,
on the legs, on the trunk, and even in
facial hair. The bites sometimes cause
itching. Children can become infested
by transmission from parents, and the
lice may live on the eyelids. An insecti-
cide lotion kills the lice and eggs.
Public healthA branch of medicine
concerned with prevention of disease
through health education, provision of
clean water supplies, sewage disposal,
safer working conditions, infection con-
trol methods, immunizations, and the
care of pregnant women and young chil-
dren. Public health functions are covered
by many people and agencies, such as
Environmental Health Officers, Medical
Officers of Environmental Health, and
the Public Health Laboratory Service.
pudendaA term that refers to the exter-
nal genitalia.
pudendal blockA type of nerve block
used to provide pain relief for aforceps
delivery. A local anaesthetic (see anaes-
thesia, local) is injected into either side
of the vaginanear the pudendal nerve.
puerperal sepsisAn infection that origi-
nates in the genital tract within 10 days
after childbirth, miscarriage, or abortion.
Once a common cause of death, it is
now easily treated with antibiotic drugs.
puerperiumThe period of time after
childbirthduring which the woman’s
uterusand genitals return to their pre-
pregnancy state.
pulmonaryRelating to the lungs.
pulmonary disease, chronic obstruc-
tiveA combination of chronic bronchitis
and emphysema, in which there is per-
sistent disruption of air flow into or out
of the lungs. Patients are sometimes
described as either pink puffers or blue
bloaters, depending on their condition.
Pink puffers maintain adequate oxygen
in their bloodstream through an increase
in their breathing rate, and remain
“pink” despite damage to the lungs. How-
ever, they suffer from almost constant
shortness of breath. Blue bloaters are
cyanotic (have a bluish discoloration of
the skin and mucous membranes) be-
cause of obesity, and sometimes oedema,
mainly due to heartfailure resulting
from the lung damage.
pulmonary embolismObstruction of
the pulmonary artery or one of itsPSYCHOSURGERY PULMONARY EMBOLISM
P