Tendon pain at the bend of the arm may be caused by long-term strain, strain and other physiological reasons, or may be caused by trauma, degenerative disease and other pathological factors. 1. Physiological reasons: the part of arm bending generally refers to the elbow joint, long-term strain of the elbow joint may lead to local soft tissue micro-injury, inducing aseptic inflammation, resulting in tendon pain, such as epicondylitis of the humerus, bursitis, etc.; long-term non-athletic people suddenly force or exercise load is too large, may cause elbow joint soft tissue strains, which may also lead to tendon pain symptoms. 2. Pathological factors: trauma to the elbow joint can also lead to the appearance of the above symptoms, such as elbow dislocation, humeral epicondylar fracture, etc.; in addition, the elbow joint degenerative diseases or autoimmune diseases, will lead to osteophytes, synovial hyperplasia, etc., may also be manifested in the tendon pain symptoms, such as osteoarthritis, rheumatoid arthritis, gout and so on. The tendon pain at the bend of the arm may also have other causes, it is recommended to go to the hospital in time, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.