Snap, crackle, and pop! It makes a catchy slogan for a breakfast cereal. But when you hear those noises in your knee, they are a cause for concern, especially when accompanied by pain.
Some people hear sounds like crackling tissue paper when they bend or straighten their knees.
Known as crepitus, the noise occurs when air bubbles are trapped in the synovial lining of the joint. It is usually harmless. But, when the crackling sounds combine with pain, the symptoms may point to a serious condition, like arthritis.
At other times, snapping sensations, cracking, and popping are symptoms of the conditions below.