Protruding bones on the lateral side of the foot include both physiological and pathological protrusions, and also include medial and lateral foot protrusions. Physiological prominence is seen in the bulge of the base of the 5th metatarsal on the lateral side, and medial prominence is seen in the bulge of the navicular region, both of which are due to individual differences and developmental differences. Physiologic medial and lateral protrusion of the foot can be caused by a large development of the base of the 5th metatarsal bone and a large development of the navicular bone or the paramedian bone, which are usually not associated with any symptoms and are not a cause for concern. Pathological protrusion is caused by local pathological changes. Protrusion of the lateral 5th metatarsal base is common due to deformed healing after a fracture and inversion of the foot, which leads to protrusion of the lateral bone. Pathological protrusion of the medial side is commonly caused by navicular tubercle, navicular epiphysitis, and valgus of the foot as well as flatfoot syndrome, all of which lead to protrusion of the medial side of the foot. Therefore, it mainly depends on whether there are symptoms to presume pathological or physiological, and if it is not clear to go to the hospital for treatment.