Left wrist bone bulge may be a normal physiological phenomenon, may also be osteophytes, tendon sheath cysts and other factors. 1. Normal physiological phenomenon: the human body ulna and radius end of the ulna and radius stem protrusion, is the normal wrist part of the small bone bulge, if the patient’s body is thin, the protrusion is more obvious. 2. Osteomalacia: If the patient lacks calcium or has long-term strain at the wrist, osteomalacia may occur at the wrist bone joint, which leads to the protrusion of the head of the wrist bone. 3. Tenosynovial cysts: If the patient has chronic trauma or infection at the wrist, or suffers from immune system diseases, the symptoms of tenosynovial cysts may occur, and this symptom will also appear in the wrist similar to the bone protrusion. 4. Osteoma: If the patient has a tumor growth at the wrist, it can also lead to wrist bone head growth. Left wrist bone enlargement may also be caused by a variety of factors, excluding physiological reasons, the patient should go to the hospital in time to avoid delaying the condition.