Ask A Scientist© Biology Archive

Author:      danb
Text:        Why do your joints pop?  For example, when I am walking my ankle 
always makes a popping sound?  I think it has something to do with the air 
(space) in the joint but I do not know.

Response #:  1 of 1
Author:      psych
Text:        One reason is that tendons snap a little like plucking guitar 
strings.  Another reason is because of a release of gas dissolved in the fluid 
of the joint.  Sometimes joints make crunchy noises due to small bone 
fragments in the joint (like sand under a steel wheel).  Joints can also make 
popping noises when they dislocate (this is usually painful).