I don’t know if you’ve noticed, but sometimes when we squat or jump, there is a ringing sound at the knee, a sound we call “popping”. Some people may stop ringing after one ringing, which is a physiological ringing and requires no special treatment. However, some people may squat and then ring, which requires special attention, the ringing represents the wear and tear of the joint, wear to a certain degree of the knee joint will appear arthritis, degenerative degeneration, and other serious cases may even lead to disability, especially in the elderly. I. What is the physiological ringing? There is joint fluid inside the joint cavity, which acts as a lubricant. The joint cavity is under negative pressure, which keeps the joint structure stable. When the joint is pulled or flexed (pulling and breaking fingers can make a popping sound), the pulling force exceeds the negative pressure of the joint cavity, and a clear cavity will appear, and the surrounding gas will diffuse rapidly into the cavity and vibrate together with the fluid, thus making a crisp sound. In other words, the physiological ringing is caused by the vibration of the gas in the joint cavity. Second, how to determine whether it is physiological ringing? Usually physiological ringing meets these conditions: 1, the sound is crisp, single and not repeated; 2, it only occurs when the joint is suddenly pulled or flexed; 3, there must be a certain period of rest for the joint between two ringing; 4, accompanied by a slight pain or discomfort, and there is often a sense of relief after the ringing. It should be noted that when you feel your knee popping does not belong to the above situation, you may have pathological changes in the knee joint, which may be meniscal injury, disc meniscus, osteoarthritis, synovial crepitus syndrome, ligament injury within the knee joint, etc. Third, most of the knee ringing in young people is a problem of the patellofemoral joint, that is, the patella moves medially or laterally, resulting in a change in the displacement pathway of the patella during knee flexion, impacting other tissues and thus causing a popping sound. Usually these patients have inversion or valgus of the knee joint. How can I tell if the popping is caused by the patellofemoral joint? Method: Have someone help you move the patella to the outside, then squat down and feel if the knee joint is still rattling. If you still have it, move the patella medially and squat again. If the popping of the knee disappears when the patella is fixed on either side, this indicates that the popping of the knee is caused by the displacement of the patella. Cause: Excessive tightness of the medial muscles will shift the patella inward, while excessive tightness of the lateral muscles will cause the patella to shift outward. Treatment: The treatment for this knee popping is of course to strengthen the medial or lateral femoral muscles and loosen the lateral or medial femoral muscles. Of course, there is also the possibility that tension in the iliotibial bundle and other muscles may cause the patella to shift. The exact cause varies from person to person.