in diagnosing different types of epilepsy
and identifying areas in the brain where
abnormal electrical activity develops.
effusionThe process by which fluid
escapes. The term also describes an ab-
normal collection of fluid, such as blood,
pus, or plasma, in the tissues or a body
cavity. An effusion can form as a result
of inflammation or changes in pressure
within blood vessels, or it can be due to
changes in blood constituents, as in
nephrotic syndrome. Effusion commonly
occurs around the lung (pleural effu-
sion) or heart (pericardial effusion) or
within joints, causing swelling.
effusion, jointThe accumulation of
fluid in a joint space, causing swelling,
limitation of movement, and usually
pain and tenderness. A joint is enclosed
by a capsule lined with a membrane
called the synovium. The synovium nor-
mally secretes small amounts of fluid to
lubricate the joint, but if it is damaged
or inflamed (for example, by arthritis) it
produces excessive fluid.
Pain and inflammation may be re-
lieved by analgesic drugs, nonsteroidal
anti-inflammatory drugs, and injections
of corticosteroid drugs. Swelling usually
reduces with rest, firm bandaging, ice-
packs, and keeping the affected joint
raised. In some cases, the fluid is drawn
out with a needle and syringe.
eggSee ovum.
egoThe conscious sense of oneself,
equivalent to “I”. In Freudian psychoan-
alytic theory, this part of the personality
maintains a balance between the primi-
tive, unconscious instincts of the id, the
controls of the superego, and the
demands of the outside world.
Ehlers–Danlos syndromeAn inherit-
ed disorder of collagen, the most
important structural protein in the
body. Affected individuals have abnor-
mally stretchy, thin skin that bruises
easily. Wounds are slow to heal and
leave paper-thin scars, and the joints
are loose and prone to recurrent dislo-
cation. Sufferers bleed easily from the
gums and digestive tract. Ehlers–Dan-
los syndrome is most often inherited in
an autosomal dominant pattern (see
genetic disorders). There is no known
specific treatment.Eisenmenger complexA condition in
which deoxygenated blood flows direct-
ly back into the circulation rather than
through the lungs, due to an abnormal
connection between the left and right
sides of the heart and pulmonary hyper-
tension. The resultant hypoxiacauses
cyanosis, fainting, and breathing diffi-
culty. The disorder most often occurs in
people with certain congenital heart
defects (see heart disease, congenital),
such as ventricular septal defect, that
have not been corrected.
The diagnosis is confirmed by cardiac
catheterization. Once Eisenmenger com-
plex has developed, surgical correction
of the original defect will not help. Drug
treatment may control symptoms.
ejaculationEmission of semen from
the penis at orgasm. Shortly before
ejaculation, the muscles around the
epididymides (the ducts where sperm
are stored; see epididymis), the prostate
gland, and the seminal vesicles contract
rhythmically, forcing the spermfrom the
epididymides to move forwards and mix
with secretions from the seminal vesi-
cles and prostate. At ejaculation, this
fluid is propelled through the urethra
and out of the body.
Because both semen and urine leave
the body by the same route, the bladder
neck closes during ejaculation. This not
only prevents ejaculate from going into
the bladder but also stops urine from
contaminating the semen (See also
reproductive system, male.)
ejaculation, disorders ofConditions
in which the normal process or timing
of ejaculationis disrupted.
In premature ejaculation, emission of
semen occurs before or almost immedi-
ately following penetration. Premature
ejaculation is the most common sexual
problem in men, and is often due to
over-stimulation or anxiety about sexu-
al performance. If the problem occurs
frequently, sexual counselling and tech-
niques for delaying ejaculation may
help (see sex therapy).
Inhibited ejaculation is a rare condi-
tion in which erection is normal, or even
prolonged, but ejaculation is abnormal-
ly delayed or fails to occur. The problem
may be psychological in origin, in whichEFFUSION EJACULATION, DISORDERS OFE