The foot is a complex body part that handles stress daily. Each foot contains 26 bones, 33 joints and more than 100 muscles, tendons and ligaments.

The anatomy of the foot is designed to support the tremendous impact and absorb the shock of the body’s weight. The foot also has the flexibility to move that weight for a lifetime.

The bones of the lower leg (tibia and fibula) connect to the foot at the ankle bone (talus) and ankle joint. The heel bone (calcaneus) is below the ankle bone and is the largest bone in the foot. In front of the heel bone are five tarsal bones that form the arch of the foot. The tarsal bones connect to the five metatarsals, the long bones that give the foot much of its length. In front of the metatarsals, more bones (phalanges) and joints form each of the toes. The big toe (hallux) has two joints and the other toes have three. The metatarsal-phalangeal joint at the base of the big toe is the largest joint in the foot and forms the ball of the foot.

Many muscles, ligaments and tendons surround the bones of the foot. Ligaments are strong connective tissues that join bones. Muscles help the foot move and provide padding, especially along the sole (bottom) of the foot. Many of the foot muscles are in four layers along the sole of the foot.

Tendons are similar to ligaments but connect muscles to bones. The largest tendon in the foot is the Achilles tendon, which connects the muscles of the calf to the heel bone. Each joint is surrounded by a joint capsule or bursa, a fluid–filled sac surrounded by ligaments and other soft tissue.

When all the parts of the foot work properly, they can support the body’s weight and move it through near-constant activity. If there is damage or injury to any part of the foot, it can quickly affect other parts of the foot or leg and disrupt foot function, making it painful to walk or even stand. Gait disturbances can result.

Many common causes of foot pain can be traced to shoes that do not fit properly. Ill-fitting shoes can cause pressure on certain points and lead to the formation of blisters, corns, calluses and bunions.