Pain underneath the middle toe of the foot may be caused by plantar tendonitis, tenosynovitis and other reasons. If the patient suffers from plantar tendonitis, it is usually due to over-exercise, frequent heavy walking, such as carrying heavy loads up and down the stairs, mountaineering and hiking, etc., which will lead to high tension in the plantar tendon membrane, and since the top of the toes is the stopping point of the plantar tendon membrane, inflammation of the plantar tendon membrane stopping point may cause pain in the middle toes or the rest of the toes. In the case of tenosynovitis, since the tendon sheaths are also present at the base of the toes, inflammation of the tendon sheaths can lead to flexion pain if the toes are subjected to uneven exercise or excessive weight bearing. In addition, patients with gout, calcium deficiency, rheumatoid arthritis, bursitis, soft tissue injuries and other diseases may also cause the above phenomenon, and it is recommended that the patient go to the hospital for diagnosis and treatment of the cause in a timely manner.