Sometimes we find that when we jump, squat or ride a bicycle our knees will pop, some people may just pop once and then stop popping, others may just squat and then pop, resulting in finally afraid to squat again. This kind of sound we call it a popping sound. The reason for these two situations is certainly not the same, when the squat does not ring once we do not need to be afraid of this situation, it is just like we break or press the finger to make a sound, but belongs to a physiological popping. It will not cause arthritis or swelling of the joints, but rather you will feel a sense of relief. In the latter case, the popping represents wear and tear in the joint, which can lead to arthritis and degenerative changes in the knee joint. The knee is the largest joint in the human body, and the upper femur is the longest and thickest bone in the body, which transmits the strong power provided by the quadriceps to the tibia, and the reverse force generated by the knee joint under pressure against deformation can be 2-4 times the body weight. The knee joint is also the most complex joint in the human body, and its structural stability requires a large number of ligaments and cartilage to maintain. The cavity in the joint formed by the joint capsule is called the joint cavity, which contains joint fluid and serves as a lubricant. The joint cavity is under negative pressure to maintain the stability of the joint structure. 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, where the surrounding gas diffuses rapidly into the cavity and vibrates together with the fluid, resulting in a crisp sound. In other words, physiological popping is caused by the vibration of the gas in the joint cavity. Second, how to determine whether your joint ringing is physiological ringing? Usually, physiological rattling meets these conditions: 1, crisp, single, non-repetitive sound 2, only occurs when the joint is suddenly pulled or flexed 3, the joint must have a certain period of rest between the two rattling 4, accompanied by a slight pain or discomfort, after the rattling often have a sense of relief When you feel that your knee rattling does not belong to the above situation, then you may have a pathological change in the knee joint, may be Meniscal damage, disc meniscus, osteoarthritis, synovial crepitus syndrome, damage to the ligaments within the knee joint, etc. In young people, the patellofemoral joint is more likely to have a problem, where the patella moves medially or laterally, resulting in a change in the displacement pathway of the patella during knee flexion, impacting other tissues and causing a popping sound. This change can be easily determined by having someone help you move the patella laterally and then squatting down to feel if the knee is still snapping. If so, 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. The cause is also well analyzed, too tight medial muscles will move the patella inward and too tight lateral muscles will move the patella outward. 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 displace the patella. The exact cause of the problem will be analyzed on a patient-by-patient basis. This is a problem with the patellofemoral joint that causes the knee to pop (usually these patients have inversion or valgus of the knee). Third, meniscal injury is also a common cause of knee popping meniscal injury: located in the medial or lateral space of the tibiofemoral joint, the sound is crisp, occurs with high frequency, often accompanied by joint interlocking (stuck, pain), this and the quadriceps and popliteal muscles also have a relationship. Milder meniscal injuries are not painful, walking or even jogging are not affected, and are easily overlooked. Long-term non-diagnosis can easily result in articular cartilage damage, which may eventually lead to osteoarthritis, even to the point of knee replacement. Therefore, minor injuries to the meniscus should be treated as early as possible. Fourth, there is another common situation due to knee instability Ligamentous laxity: when the joint activity is too large, the ligaments elongate and then return with a muffled sound, which usually occurs on both sides and is easily seen in thin people. However, there are many other causes of knee popping: disc meniscus, synovial crepitus syndrome osteoarthritis, joint free bodies, old damage to the cruciate ligament, insufficient joint fluid, etc. may cause the knee to pop. It may be difficult for you to judge about the popping. The advice to you is that if you are sure that you are not physiologically popping and you think that this knee popping is affecting your life, then you can go to a professional therapist to help you. If you find the right cause and combine it with the right treatment, it is quite possible for the knee popping to disappear completely.