Crepitus can easily be created and observed by exerting a small amount of force on a joint, thus 'cracking it'.
A refractory period of about 20 minutes exists where the joint cannot be stimulated to produce crepitus after being cracked until the nitrogen gas dissolves back into the synovial fluid.
[1] In soft tissues, crepitus can be produced when gas is introduced into an area where it is normally not present.
Crepitus is often loud enough to be heard by the human ear, although a stethoscope may be needed to detect instances caused by respiratory diseases.
In times of poor surgical practice, post-surgical complications involved anaerobic infection by Clostridium perfringens strains, which can cause gas gangrene in tissues, also giving rise to crepitus.