A protruding bone under the ankle may be due to the following reasons: 1. Normal bony protrusions. In the normal human body, there are some bony protrusions below the ankle joint, such as the talus of the heel bone, the navicular tuberosity, the dice bone, etc. These parts have protrusions themselves, and in thinner patients, these protrusions look more obvious. 2. caused by the paravicular bone. In this part of the navicular tuberosity, there may be congenital hereditary factors that lead to the production of the paravicular bone. If this phenomenon occurs, there will be a bony protrusion here and it may be accompanied by pain in this area. 3. avulsion fracture of the foot, for example, when the ankle joint is sprained, there may be an avulsion of the foot and there will be a significant bony protrusion in this area and it will be accompanied by pain. 4. old injury, for example, if the patient has had an old fracture of the ankle joint or foot, then after its recovery may develop this condition due to excessive osteophytes.