A foot is a part of the body in many animals. While the animal is standing, its feet touch the ground and support its weight. The structure of feet also allows animals to walk, run, and jump.

Structure and function

The structure of the foot depends on the animal. The simplest feet are not truly feet at all. Mollusks, including snails and clams, have one foot that allows them to move. However, the mollusk's foot is just a special muscle; it does not contain bones. What are called feet in insects are just the lower parts of their legs.

True feet are found in vertebrates, or animals with backbones. Vertebrates have a foot attached to the end of each leg. The feet are made up of bone, muscle, and connective tissue. Soft or padded feet are known as paws. Feet are divided into digits, or fingers and toes. The ends of the digits have hardened skin formed into claws, nails, or hooves.

Monkeys and apes have feet that look like human feet. Unlike human feet, however, the feet of monkeys and apes are flat, not arched, on the bottom. Monkeys and apes can also use their feet to grasp things; they use their big toes like thumbs.

Some animals, such as humans and bears, place the full length of their feet on the ground while walking. In other animals, such as cats and dogs, the heels never touch the ground. In animals such as horses and deer, the heels and even most of the toes do not touch the ground. Only the hooves, at the tip of one or two toes, hit the ground while they walk or run. Running on tiptoe lets horses and deer run very fast.

Human foot

The human foot has a heel, a middle portion called an instep, and toes. The bottom of the foot is called the sole. The ball of the foot is the part of the sole behind the toes.

Each foot has 26 bones. The bones form two arches that allow humans to stand and walk upright. One arch extends from heel to toes. It absorbs the shock of walking. The other arch reaches across the ball of the foot. It helps to spread the weight of the body over the foot.

Joints in the feet make the motion of walking very smooth. The ankle joint, above the heel, acts as a hinge between the leg and the foot. The toes also have joints that let the foot bend easily.

People have long used the average length of a human foot to measure things. This practice goes back as far as ancient Greece and Rome. Even today a measurement of 12 inches is called a foot.

Podiatry

Medical care of the feet is called podiatry. Podiatrists are doctors who treat diseases, injuries, and other problems of the human foot. Common foot problems include a fungal infection called athlete's foot, ingrown toenails, and painful spots called corns. When children are born with malformed feet, podiatrists may prescribe special shoes or perform surgery to correct the shape of the feet.