Possible causes of elbow joint bending noise include physiological causes such as slight joint misalignment during activities, and pathological causes such as ligament injury and joint inflammation. 1. Physiological reasons: when the elbow joint bends, sometimes it will produce rattling sound because of the slight friction of the joint surface, which is often not accompanied by other clinical symptoms such as elbow pain, which is a normal phenomenon and generally does not require special treatment. 2. Pathological reasons: when the elbow joint ligament injury or joint inflammation and other pathological conditions, due to joint instability, activities will produce obvious noise. In addition, it may be accompanied by other uncomfortable symptoms, such as elbow pain and limitation of movement. If the elbow joint makes an obvious noise when bending or is accompanied by other uncomfortable symptoms, it is recommended to consult a doctor in time to clarify the cause and obtain proper diagnosis and treatment.