Pain in the bend of the arm is commonly caused by degenerative osteoarthritis of the elbow joint, cold in the elbow joint, trauma to the elbow joint, etc., as follows: First, degenerative osteoarthritis of the elbow joint: common in middle-aged and elderly patients, who usually like to exercise, too much activity of the elbow joint will cause serious wear and tear of the elbow joint surface, damage to the cartilage of the elbow joint, osteophytes around the elbow joint, which will manifest as pain in the elbow joint, limited activity, and even the appearance of Elbow joint stiffness. Second, the elbow joint is cold: at night when sleeping, the ambient temperature is too low will lead to the elbow joint being cold, manifesting as elbow joint pain and limited movement. Third, trauma to the elbow joint: fractures and dislocations of the elbow joint can cause pain, swelling, and limited movement of the elbow joint, and X-rays can confirm the existence of fractures and dislocations. The pain in the elbow joint should be diagnosed and treated promptly, and the corresponding treatment should be chosen according to different causes, so that the pain in the elbow joint can be relieved or even disappear completely. It is necessary to pay attention to the protection of the elbow joint in daily life to avoid cold and trauma.