If the foot navicular bone protrudes from childhood, it may be a congenital abnormality or deformity of bone growth and development. A long-term abnormality or deformity of the bone will cause continuous compression and stimulation of the surrounding tissues, which will lead to a bursa at the site of compression, and the bursa will cause pain if an inflammatory reaction occurs. Secondly, if the foot navicular protrusion is acquired, what needs to be ruled out is the occurrence of local bone and soft tissue damage and tumor. The occurrence of tumor in bone or local soft tissue will lead to a significant protrusion in appearance, and if the tumor invades the peripheral nerve or occurs necrosis and inflammatory reaction, it will lead to the occurrence of pain. Finally, if there is a previous fracture of the navicular bone or a deformed healing of the fracture end, there will also be a protrusion in appearance, and the pain will occur over time due to the appearance of traumatic arthritis.