Application of Ergonomics of the Foot
Figure 30.1 shows the bones of the foot and ankle. The toes (foot fingers) are divided into metatarsals and
three phalanges (except for the big toe, which only has two phalanges). In supporting the body, the calcaneus
(heel) supports 50% of the weight, the first and second metatarsals 25%, and the third, fourth, and fifth meta-
tarsals 25%. In between are two arches: (1) the medial arch (calcaneus, the talus, the navicular, the cuneiform
bones, and the first, second, and third metatarsals) and (2) the lateral arch (calcaneus, talus, cuboid, and the
fourth and fifth metatarsals). The plantar facia is a fibrous tissue that forms the arch underneath your foot
from the heel to the toes. If it weakens, the facia can cause pain to either the heel end or the toe end.