Scientists warn against finger cracking, as this may harm the joints. They have even modeled a joint to find out the origin of cracking sound and its effect on joints.
According to the research, sharp stretching of knuckles results in making foam out of synovial fluid which turns into numerous air bubbles that burst with a cracking sound. Another approach suggests that finger cracking may be caused by a tendon rubbing against the uneven tendons surface. Irrespectively of the cracking sound source, non-natural load applied towards knuckles may destroy cartilages and end up with a fear of joint diseases, states Edmund Edelma, the president of German Rheumatologists Association (BDRh).
Source of the image: sxc.hu/profile/lusi.