Your feet quite literally let you walk all over them, so you might not think they’re all that special – but the human foot is a complicated anatomical structure. Each one is formed from twenty eight bones (which accounts for nearly one quarter of all the bones in our bodies!), thirty distinct joints, and more than one hundred muscles, tendons, and ligaments. Each of these plays a role in providing support, flexibility, and mobility.
The bones of the foot provide structure: this begins at the top with the ankle joint (talus), which is stabilized by the ends of the bones in the lower leg, allowing up-and-down motion, and also includes the heel bone (calcaneus), which allows for side-to-side movement. The five tarsal bones below the ankle interlock at the joints in a specially flexible way that allows them to be more or less rigid depending on the direction the surrounding muscles are twisted; this helps the foot conform to the surface it’s in contact with. They connect with the metatarsals, the five long bones in the longest part of your foot that form the arch, which in turn are connected to the phalanges – the fourteen bones that make up the toes. These, particularly the big toe, contribute to the ability to walk.
Tendons are tough bands of tissue that attach muscle to bone; the best-known is the Achilles tendon, which connects the muscles of the calf to the heel bone and creates the motion to stand on your toes – this makes it essential to running and jumping, which is often how it gets injured. The smaller posterior and anterior tibial tendons run along the arch of the foot from the ankle and allow the feet to turn inward or outward, as well as curl or straighten the toes.
Ligaments are tissues that connect bone to bone, which contributes to the structure of the foot, and also surround the many joints to create a protective sac. The plantar fascia is the largest, and the most well-known, ligament in the foot – it runs along the sole of the foot and helps form the arch, providing balance and flexibility.
The twenty muscles in each foot provide both movement and shape: the extensors create a raising motion in the toes while the flexors stabilize them, the tibilias posterior contributes to the arch, and the tibilias peroneal helps move the ankle.