Popping and Cracking in Joints..

[SkullZoRz]

I've always wondered two things:

What happens when you crack your fingers?
I did wushu (modern kung fu) some time ago for like 2 years and every session we would stretch our palm backwards (well, stretching the fingers, palm and forearms).

You know when you grab the top of your fingers and push then backwards but also stretching the forearms by also pushing the palm back... I'll try to find a picture somewhere :P
http://www.lincoln.edu.ar/comp/intro/graphics/ergo_forearmstretch.jpg

And what makes your knees/hips "pop"?

I used to do theese kicks reguarly:
http://www.shouyuliang.com/images/newsletter/v3n4/a6p1.jpg
http://www.shouyuliang.com/images/newsletter/v4n1/a6p1.jpg

Theese kicks caused my hips to "pop" or making a popping sound and it kinda hurt alittle.

Thanks in advance!

[l0stsheep]

[ QUOTE ]
The "crack" comes because of a change in the synovial fluid, the lubricant that bathes the joints. When finger bones are suddenly stretched apart, the space between the joints widens, and an air bubble forms in the synovial fluid. The bubble quickly bursts and makes a sharp sound.

-Peter Bonafede, M.D., Medical Director of the Providence Arthritis Center at Providence Portland Medical Center


[/ QUOTE ]

I just found this by searching on Google. haha... /forum/images/graemlins/wink.gif
Joints in your fingers would also be the same as joints in hips.