The causes of left foot ring finger pain are left foot ring finger tenosynovitis, degenerative arthritis, etc., as follows: First, left foot ring finger tenosynovitis: too much walking causes toe flexor tendons and tendon sheaths to rub against each other, and tendon sheath inflammation, and sometimes the pain is accompanied by joint popping, which is mainly caused by the tendon sheaths stuck in the tendons. Second, degenerative arthritis: most commonly seen in elderly patients, with the age of joint cartilage wear and tear loss, joint space will narrow, interphalangeal arthritis occurs when the interphalangeal joint will occur pain, and also accompanied by deformation. Regardless of the cause, it is important to reduce weight-bearing walking, while foot soaks and hot compresses can be given, which can relieve symptoms and improve function.