Finger cracking is a rather bad habit, but it feels really good. Of course, a person who stands beside you will freak out and will try to convince you to stop doing it. ‘Your hands will shake when you are old’, goes the commonplace warning.
The good new for finger crackers is that there is no scientific proof that regular cracking would cause arthritis – at least according to John Indalecio, a New York hand therapist. What happens during finger cracking? Joints are situated between two bones and they are protected by both cartilage and the joint capsule. The joint capsule is filled with fluid, which contains three gases: oxygen, carbon dioxide and nitrogen. When joints are pressed, these gas bubbles burst, not the bones are cracking. Allegedly, there is no problem if it feels good, but if you feel pain, you probably should see a doctor.
In the video below, you can see at about 00:30 what actually happens in a finger when the joints are cracked.
http://www.youtube.com/watch?v=kxzkm5-TE9w