The arch of the foot is located on the bottom of the foot. The upward concave part of the sole of the foot is the area of the arch. The arch consists of an internal and external longitudinal arch in the anterior-posterior direction and a transverse arch in the left-right direction. The arch consists of the bony structures of the heel, tarsal and metatarsal bones, as well as auxiliary structures such as ligaments and tendons. The arch has the ability to withstand pressure and cushion shock, as well as protect the plantar vessels and nerves. Flat feet occur when the arch collapses due to damage to these structures caused by trauma, disease or developmental abnormalities. Flat feet reduce walking motion, fatigue and foot pain, and may cause compression of the plantar vessels and nerves. If the arch rises too far upward, high arched feet are formed. Both flat feet and high arched feet are arch abnormalities. It is recommended to seek medical attention to identify the cause of the foot arch abnormality and receive regular treatment.