The normal human foot forms a slightly raised shape, mainly because of the existence of the human foot arch. The arch is formed by the metatarsal bones of the human body, that is, the metatarsal bones, and the metatarsal bones and the ankle bones connected at a specific angle, forming the arch of the human body and the protrusion of the back of the foot. The bones of the back of the normal human foot are the second and third metatarsal bones, and the tarsometatarsal joint where the second and third metatarsals are connected. These two bones and the joints form a relatively high angle, thus allowing the human foot and ankle to meet some functions and roles. The main function is to cushion the weight of the human body through the arch and tarsometatarsal joint, so that the pressure on the foot and ankle can be shared by the arch and joint, and to make the human foot and ankle joint more flexible and more capable of movement.