Osteochondritis dissecans (OCD) is a joint disorder in which cracks
form in the articular cartilage and the underlying subchondral bone. It
is caused by blood deprivation in the subchondral bone, which leads to
death of subchondral bone tissues in a process called avascular
necrosis. The bone is then reabsorbed by the body, leaving the
articular cartilage it supported prone to damage. The result is
fragmentation of both cartilage and bone, and the free movement of
these osteochondral fragments within the joint space, causing pain and
further damage. In humans, OCD is a rare disease, occurring in only 15
to 30 people per 100,000 in the general population each year. Although
rare, it is an important cause of joint pain in physically active
adolescents. As their bones are still growing, adolescents are more
likely than adults to recover from OCD, attributable to the growing
bone's ability to repair damaged or dead bone tissue and cartilage in a
process called bone remodeling. While OCD may affect any joint, the
knee tends to be the most commonly affected, and constitutes 75% of all
cases.
Read the rest of this article:
<http://en.wikipedia.org/wiki/Osteochondritis_dissecans>
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Today's selected anniversaries:
1868:
Astronomer Pierre Janssen discovered helium while analyzing the
chromosphere of the sun during a total solar eclipse in Guntur, India.
<http://en.wikipedia.org/wiki/helium>
1877:
Asaph Hall discovered Phobos , the larger of Mars' two moons, six days
after discovering Deimos, the other one.
<http://en.wikipedia.org/wiki/Phobos_%28moon%29>
1920:
The Nineteenth Amendment to the United States Constitution was
ratified, guaranteeing women's suffrage in that country.
<http://en.wikipedia.org/wiki/Women%27s_suffrage_in_the_United_States>
1948:
Australia completed a 4–0 Ashes series win, earning them the nickname
of "The Invincibles" for being the first Test cricket match side to
play an entire tour of England without losing a match.
<http://en.wikipedia.org/wiki/Fifth_Test%2C_1948_Ashes_series>
1966:
Vietnam War: Members from D Company of the 6th Battalion of the Royal
Australian Regiment were surrounded and attacked on all sides by a much
larger Viet Cong unit at the Battle of Long Tan, but held them off for
several hours until reinforcements arrived.
<http://en.wikipedia.org/wiki/6th_Battalion%2C_Royal_Australian_Regiment>
1989:
Leading Colombian presidential hopeful Luis Carlos Galán was
assassinated during a public demonstration in the town of Soacha,
Cundinamarca.
<http://en.wikipedia.org/wiki/Luis_Carlos_Gal%C3%A1n>
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Wiktionary's word of the day:
ness (n):
(geography) A promontory; a cape or headland
<http://en.wiktionary.org/wiki/ness>
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Wikiquote quote of the day:
Tho' the world could turn from you,
This, at least, I learn from you:
Beauty and Truth, tho' never
found, are worthy to be sought,
The singer, upward-springing,
Is grander than his singing,
And
tranquil self-sufficing joy illumes the dark of thought.
--Robert Williams Buchanan
<http://en.wikiquote.org/wiki/Robert_Williams_Buchanan>