[net.med] knuckle-cracking

markp (01/21/83)

Some years ago I picked up the annoying habit of cracking my knuckles.
Only now am I finally able to quit doing it, and I'm wondering if anyone
out there can speak with authority on some questions I have --

What exactly is the mechanism by which knuckles will "crack" or "pop" when
bent or pulled?

What damage and/or deterioration may be expected as a result of extended
periods of frequent deliberate cracking of the knuckles?

Can knuckle-cracking be a self-perpetuating habit in that it sets up
conditions in the joints which cause them to stiffen unless cracked
occasionally?

Are there many people who have this habit?  Can anyone speak of ill effects
(or the lack thereof) as a result of long, personal experience?

What about the normal-motion-induced cracking of other joints?


Mark R. Paulin
...decvax!teklabs!tekmdp!markp

dfh (01/24/83)

  Speaking of cracking joints, my ankle joints crack *every* time I walk up
a flight of stairs, and have done so as long as I can remember (I'm 24).  I
sometimes sound like a walking bowl of rice krispies...  I remember my
pediatrician dismissed this as a 'growing' related phenomena.  When I'm 50
I suppose my ankles will be in terrible shape.  Are there any other folks
with this problem ?

leichter (01/26/83)

The last article I saw on the subject (not that long ago and in some medical
journal) stated that the actual mechanism in knuckle (or other joint) cracking
was still unknown.  The prevailing "best guess" was that it was caused by
bubbles somehow getting introduced into the synovial fluid - in which the joints
are bathed - and then bursting.  I guess in this picture the feeling of relief
you sometimes get when cracking, say, your back when it's stiff is the result
of a bubble finally bursting and relieving a pressure build-up within the joint.
								-- Jerry
							decvax!yale-comix!leichter
(oops, one tab too many...)