Bone cysts, also known as bone cysts, are mainly caused by bacteria that grow and multiply in the bone area, and are later eliminated and wrapped by normal tissues, forming cysts in the bone area. For bone cysts, the source of bacteria is mainly from other parts of the body, such as skin infections or gastrointestinal infections, pneumonia, the bacteria will enter the bloodstream and then follow the blood to the bones to grow and multiply. Later on, the patient’s resistance will increase and the growing bacteria will be killed and wrapped with normal tissues to form a bone cyst.