WebMD demonstrates that there are 26 bones in the foot. It can be divided into the hindfoot, the midfoot and forefoot. Overall, it contains 33 joints and over 100 tendons, ligaments and muscles.
The heel and arch of a foot are designed to bear weight. Due to the interplay of muscles and nerve endings, foot pain or misalignment can cause a host of other problems. Wikipedia shows that over- and under-pronating, which refer to the foot striking the ground at the arch and the outside of the foot, respectively, are two of the leading causes of chronic pain. Special inserts can be purchased which help the foot cycle through a neutral pronation.