HIP, CONGENITAL DISLOCATION OF
H
PERFORMING A HIP REPLACEMENT
In this operation, the surgeon pushes aside or cuts through the surrounding
muscles to expose the hip joint. The femur (thigh bone) is cut and the pelvis is
drilled to make room for the two components of the artificial joint. These parts
are secured in place, the femur is repaired, and the muscles and tendons are
replaced and repaired.
Alte rnative
sites of incision
P e lv is
T r o c h a n t e r
B a ll
- S h a f t
Components
An artificial hip joint has two parts. The ball
and shaft are metal; the socket may be metal
or plastic.
After
This X-ray shows
the artificial hip
joint in position
after surgery.
R e p l a c e m e n t
j o i n t
F e m u r
F e m u r
bony prominence on the outside of the
f e m u r
(thigh bone), and does not indi-
cate disease.
Clicking of the hip may sometimes
be heard during examination of new-
born babies; in this instance, it indicates
possible dislocation of the hip
(see
d e v e l o p m e n t a l h i p d y s p l a s i a ) .
hip, congenital dislocation of
See
d e v e l o p m e n t a l h i p d y s p l a s i a .
hip dysplasia, developmental
See
d e v e l o p m e n t a l h i p d y s p l a s i a
.
hippocampus
A structure in the
l i m b i c s y s t e m
of the
brain. The hippocampus, consisting of a
band of
g r e y m a t t e r ,
is involved with
some learning processes and long-term
memory storage.
Hippocratic oath
A set
of ethical
principles
that
are
derived from the writings of the Greek
physician Hippocrates that is concerned
with a doctor’s duty to work for the
good of the patient.
hip replacement
A surgical procedure to replace all or
part of a diseased
h i p
joint with an arti-
ficial
substitute. The
replacement
is
most often carried out in older people
whose joints are stiff and painful as a
result of
o s t e o a r t h r i t i s .
It may also be
needed if
r h e u m a t o i d a r t h r i t i s
has spread
to the hip joint or if the top end of the
femur (thigh bone) is badly fractured
(see
f e m u r , f r a c t u r e o f ) .
Hirschsprung’s disease
A
c o n g e n i t a l
disorder
in
which
the
r e c t u m ,
and sometimes the lower part of
the
c o l o n ,
lack the ganglion cells that
control the intestine’s rhythmic contrac-
tions. The affected part of the colon
becomes narrowed and blocks the move-
ment of faecal material.
The disease is rare and tends to run
in families. It occurs about four times
more often in boys. Symptoms, w hich
include constipation and bloating, usu-
ally develop in the first few weeks of
life.
The
child
usually
has
a
poor
appetite and may fail to grow properly.
A
b a r i u m X - r a y e x a m i n a t i o n
can show the
narrowed segment of the intestine. A
b i o p s y
may also be taken. Treatment of
Hirschsprung’s disease involves removing
the narrowed segment and rejoining the
normal part of the intestine to the anus.
hirsutism
Excessive hairiness, w hich particularly
appears in women. The additional hair
is coarse in texture and grows in a male
pattern on the face, trunk, and limbs.
Hirsutism can be a symptom of certain
conditions,
such
as
p o l y c y s t i c
o v a r y
s y n d r o m e
and congenital
a d r e n a l h y p e r -
p l a s i a ,
in w hich the level of naturally
occurring male hormones in the blood
is abnormally high. Hirsutism can also
be a result of taking anabolic steroids
(see
s t e r o i d s , a n a b o l i c ) .
More commonly,
however, hirsutism is not a sign of any
disorder at all; it occurs m ildly in many
normal
women,
especially
after
the
m e n o p a u s e ,
in w hich hormone balance
is upset (See also
h y p e r t r i c h o s i s . )
hirudin
An anticoagulant contained in the saliva
of leeches
(see
l e e c h )
that
prevents
blood from clotting.
histamine
A chemical present in cells (mainly
m a s t
c e l l s )
throughout
the
body
that
is
released during an allergic reaction (see
a l l e r g y ) .
Histamine activates two main
types of receptors: H, and H 2. H, activa-
tion is responsible for the swelling and
redness that occur in
i n f l a m m a t i o n .
It also
narrows the airways in the lungs and
causes itching. H 2
activation stimulates
acid production by the stomach, but in
large amounts it can irritate the stomach
lining, causing
g a s t r i t i s
or
p e p t i c u l c e r s .
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