Foot Anatomy ​

 

How is the 'Human Foot' structured

The parts of the foot and its functions are unique but can also contribute to common foot problems. The many bones, ligaments, and tendons of the foot help you move, but they can also be injured and limit your mobility. 

This article will give an overview of foot anatomy and foot problems that come from overuse, injury, and normal wear and tear of the foot.

 

Foot Anatomy

There are many parts of the foot and all have important jobs. Each foot has 26 bones, over 30 joints, and more than 100 muscles, ligaments, and tendons. These structures work together to carry out two main functions:1

• Bearing weight

• Forward movement (propulsion)

The foot must be flexible to adapt to uneven surfaces and remain stable when you’re walking. 

The foot has three parts: the forefoot, midfoot, and hindfoot. There are bones, joints, muscles, tendons, and ligaments in each of these sections.

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Orientation of the Foot

The bottom part of the foot is the sole. The padded area on the bottom of the foot is known as the plantar aspect. The top part of your foot above the arch is the instep. In medical terms, the top of the foot is the dorsum or dorsal region.3

 Anatomy of the Lower Leg Muscles.

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Bones

There are 26 bones in the foot, and they can be categorized according to their location.2

Forefoot Bones

The forefoot bones include long bones in the middle of the foot as well as smaller toe bones.

• Phalanges: These are the toes. They are made up of a total of 14 bones: two for the big toe and three for each of the other four toes.

• Metatarsals: These are five long bones that go out from the base of each toe to the midfoot. The first metatarsal bone leads to the big toe and plays an important role in forward movement. The second, third, and fourth metatarsal bones provide stability to the forefoot.

• Sesamoid bones: These are two small, oval-shaped bones beneath the first metatarsal on the underside (plantar surface) of the foot. It is embedded in a tendon at the head of the bone (the part closest to the big toe). Its role is to reinforce and reduce stress on the tendon.

 

Midfoot Bones

The midfoot is made up of five irregularly shaped bones called the tarsals. The tarsals form the arch of the foot. The arch plays a key role in weight-bearing and foot stability.

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The midfoot bones include:

• Navicular

• Cuboid

• Medial cuneiform

• Intermediate cuneiform

• Lateral cuneiform

 

Hindfoot

There are only two bones of the hindfoot, but they are the biggest bones in the foot.

• Calcaneus: This is the large bone at the heel of the foot (heel bone). Its main function is to transfer most of the body weight from the legs to the ground.

• Talus: This is the bone that sits between the calcaneus and the two bones of the lower leg (the tibia and fibula). It helps transfer weight and pressure across the ankle joint.

 

Joints

Joints are the part of the foot where two bones come together. While each foot has 30 joints, the following list gives a few examples.2

Your big toe has two joints: 

• The metatarsophalangeal joint at the base of the toe and the interphalangeal joint just above it

The other four toes have three joints each:3

• The metatarsophalangeal joint at the base of the toe

• The proximal interphalangeal joint in the middle of the toe

• The distal phalangeal joint near the tip of the toe

The midfoot has the tarsometatarsal joints (also called the Lisfranc joints), which connect the tarsal and metatarsal bones and provide stability to the arch of the foot.5

The subtalar joint and the transverse tarsal joint are also important structures of the foot:2

• The subtalar joint is where the calcaneus connects to the talus. 

• The transverse tarsal joint is what helps you turn your foot inward and outward (supinate and pronate) at the ankle. 

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Muscles

The muscles that control the movements of the foot start in the lower leg and are attached to the bones in the foot with tendons.

These are the main muscles that facilitate movement in the foot:2

• Tibialis posterior: The muscle that supports the arch of the foot

• Tibialis anterior: The muscle that allows the foot to move up

• Peroneus longus and brevis: The muscles that move the outside of the ankle

• Extensors: The muscles that raise the toes when stepping

• Flexors: The muscles that stabilize the toes and curl them under

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Tendons

Tendons are fibrous connective tissues that attach muscles to bones. There are three major tendons that help with movement of the foot: forward bending of the foot (flexion) and backward bending of the foot (dorsiflexion).

• Achilles tendon: This is the most notable tendon of the foot that runs from the calf muscle to the heel. It is the strongest and largest tendon in the body that makes it possible to run, jump, climb stairs, and stand on your toes.6

• Tibialis posterior: This tendon attaches the calf muscle to the bones on the inside of the foot and supports the arch of the foot.

• Tibialis anterior: This runs from the outer bone of the lower leg to the tarsals and first metatarsal, which enables dorsiflexion.

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Ligaments

Ligaments are fibrous connective tissues that connect bone to bone. There are over 30 ligaments in the feet, but these are a few of the most important ones.

• Plantar fascia: This is the longest ligament of the foot that runs from the heel to the toes to form the arch. The plantar fascia provides strength for walking and assists with balance.

• Plantar calcaneo-navicular: This is a ligament that connects the calcaneus to the talus. Its role is to support the head of the talus.

• Calcaneocuboid: This is the ligament that connects the calcaneus to the tarsal bones. It helps the plantar fascia support the arch of the foot.

 

Other ligaments in the foot include;

• Anterior talofibular ligament

• Calcaneofibular ligament

• Posterior talofibular ligament

• Deltoid ligament

• Spring ligament

• Lisfranc ligaments

• Inter-metatarsal ligaments

• Anterior inferior tibiofibular ligament​