OSSIFICATION
OSTEOCHONDRITIS DISSECANS
OSSIFICATION
Secondary
Epiphysis
Articular
ossification
cartilage
Growth
plate
Blood
vessel
Marrow
cavity
consists of
cartilage
Diaphysis
(shaft) is
already
ossified
LONG BONE OF A NEWBORN
centre
Growth
plate
produces
cartilage
to lengthen
bone .
Blood
vessels
form new
branches
to nourish
growing
tissue
protects
end of
bone
Ossified
growth
plate
Marrow
cavity
LONG BONE OF A CHILD
LONG BONE OF AN ADULT
ossification The process by which
bone
is formed, renewed, and repaired, starting
in the embryo and continuing through-
out life. There are 3 main situations in
which ossification occurs: bone growth,
during which new bone forms at the
epiphyses
(ends) of bones; bone renew-
al as part of normal regeneration; and
bone repair following a
fracture.
In newborn babies, the
diaphysis
(shaft)
has begun to ossify and is composed
mainly of bone, while the epiphyses are
made of cartilage that gradually hard-
ens. In children, growth plates produce
new cartilage to lengthen the bones,
and further bone forms at secondary
ossification centres in the epiphyses. By
the age of 18, the shafts, growth plates,
and epiphyses have all ossified and
fused into continuous bone.
osteitis Inflammation of
bone.
The most
common cause is infection (see
osteo-
myelitis).
Other causes are
Paget's disease
and
hyperparathyroidism
.
osteitis deformans An alternative term
for
Paget's disease
.
osteo- A prefix denoting a relationship
to bone, as in
osteoporosis
, a condition
in which the bones thin and weaken.
osteoarthritis A common
joint
disease
characterized by degeneration of the
cartilage that lines joints or by formation
of
osteophytes
, leading to pain, stiff-
ness, and occasionally loss of function.
Osteoarthritis is due to wear and tear on
joints, weight-bearing joints being the
most commonly affected. Weakness and
shrinkage of surrounding muscles may
occur if pain prevents the joint from
being used regularly. Affected joints
become enlarged and distorted by osteo-
phytes. Osteoarthritis occurs in almost
all people over 60, although not all have
symptoms. Factors that lead to its earlier
development include excessive wear of,
or injury to, a joint; congenital deformi-
ty or misalignment of bones in a joint;
obesity;
or inflammation from a disease
such as
gout
. Severe osteoarthritis affects
3 times as many women as men.
There is no cure for osteoarthritis.
Symptoms can be relieved by
nonsteroid-
a anti-inflammatory drugs, analgesics,
injections of
corticosteroid drugs
into
affected joints, and
physiotherapy
. In
overweight people, weight loss often
provides relief of symptoms. Surgery for
severe osteoarthritis includes
arthro-
plasty
and
arthrodesis
.
osteochondritis dissecans Degenera-
tion of a
bone
just under a joint surface,
causing fragments of bone and cartilage
to become separated, which may cause
the joint to lock. The condition common-
ly affects the knee and usually starts in
adolescence. Symptoms include aching
discomfort and intermittent swelling of
the affected joint.
If a fragment has not completely sepa-
rated from the bone, the joint may be
O
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