Anatomy and Common Injuries of the Feet or Ankles (2023)

The anatomy of the foot and its function can predispose to common foot problems.

Common causes of foot pain include plantar fasciitis, bunions, flat feet, heel spurs, mallet toe, metatarsalgia, claw toe, and Morton's neuroma. If your feet hurt, there are effective ways to ease the pain This article provides an overview of foot anatomy and foot problems that come from overuse, injury, and normal wear and tear of the foot.

Foot Anatomy

Each of your feet has 28 bones, 30 joints, and more than 100 muscles, ligaments, and tendons. These structures work together to carry out two main functions:

• Weight-bearing
• Propulsion (forward movement)

Plus, the foot must be flexible to adapt to uneven surfaces and remain stable.

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

Bones

Forefoot 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 extend from the base of each toe to the midfoot. The first metatarsal bone leads to the big toe and plays an important role in propulsion (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 nearest to the big toe). Its role is to reinforce and reduce stress on the tendon.

Midfoot Bones

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

These bones include:

• Navicular
• Cuboid
• Medial cuneiform
• Intermediate cuneiform
• Lateral cuneiform

Hindfoot

• Calcaneus: This is the large bone at the heel of the foot, also known as the 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 where two bones meet. In the feet, each 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: the metatarsophalangeal joint at the base of the toe, the proximal interphalangeal joint in the middle of the toe, and the distal phalangeal joint closest to the tip of the toe.

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:

• Tibialisposterior: The muscle that supports the foot's arch
• Tibialis anterior: The muscle that allows the foot to move upward
• Peroneus longus and brevis: The muscles that control movement on the outside of the ankle
• Extensors: The muscles that raise the toes to make it possible to take a step
• Flexors: The muscles that stabilize the toes and curl them under

Tendons

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

• Achilles tendon: This is the most notable tendon of the foot which 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.
• Tibialisposterior: 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.

Ligaments

Ligaments are fibrous connective tissues that connect bone to bone. These are the primary ligaments of the foot:

• 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 calcaneonavicular: 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.

Common Foot Problems

The average person has walked about 75,000 miles by age 50. Given how many moving parts there are in the foot, it's not surprising how vulnerable it is to injury or overuse.

Nine conditions specific to the foot can cause pain, restrict the movement of the foot, or lead to foot instability.

Plantar Fasciitis

Plantar fasciitis is caused by microtears in the thick fibrous tissue on the underside of the foot, usually due to overstretching. Symptoms include pain in the heel and arch that is often worse in the mornings. Plantar fasciitis is common among-distance walkers or runners.

Bunions

A bunion is a bony protrusion on either the inside edge of the foot or the pinkie toe side. Bunions form gradually when the bones in the foot become misaligned, often due to wearing shoes that don't fit well or that squeeze the toes together tightly.

The big toe can bend so far inward that it actually crosses under or over the adjacent toe, causing a secondary misalignment called a hammertoe. Usually, a painful callous will form on top of the second toe.

Flat Feet

Pes planus (flat feet) is when the arc of the foot straightens out, often so completely that the entire sole comes in contact with the floor.

Flat feet can cause pain in the midfoot area as well as swelling of the ankle and arch. The imbalance can also lead to hip, knee, or lower back pain.

Pes planus can be congenital (meaning you are born with it), but more often it is a result of age or injury. Between 20% and 30% of people have some degree of flat-footedness.

Heel Spurs

As the largest bone in the foot, the calcaneus (heel) is prone to injury caused by faulty foot biomechanics (meaning problems with your gait).

One of the more common is the development of bony overgrowth called heel spurs that cause severe pain when standing or walking. Also known as calcaneal spurs, heel spurs are most common in people who have plantar fasciitis, flat feet, or high arches.

Mallet Toe

With a mallet toe, the joint in the middle of a toe becomes permanently bent to the extent that it points downward.

Mallet toes develop because of an imbalance in the muscles, tendons, or ligaments that hold the bones straight. As with bunions and hammertoe, mallet toe often forms as a result of wearing ill-fitting shoes, although it can also be caused by trauma or certain diseases.

Metatarsalgia

Metatarsalgia is pain under the ball of the foot. It is often the result of pressure caused by high heel shoes or from conditions such as arthritis, nerve compression, or fractures or tears in ligaments that support the ball of the foot.

Claw Toe

A claw toe is a deformity in which a toe bends downward from the middle joints and can sometimes even curl under the foot entirely. When this happens, callouses or corns will form on top of the affected toe. Sometimes, a corn can place pressure on nerves in the foot, causing pain.

Morton's Neuroma

This is a common problem in which compression on a nerve in the ball of the foot causes burning, tingling, and pain near the third and fourth toes. High heels are most often the culprit. Morton's neuroma can make you feel like you have a pebble in your shoe or on a fold in your sock.

Medical Conditions That Can Cause Foot Problems

The feet are subject to a variety of medical problems, including:

• Sprainsand strains
• Ruptured tendon or ligament
• Bone fractures
• Tendinitis (tendon inflammation)
• Osteoarthritis ("wear-and-tear arthritis")
• Rheumatoid arthritis (autoimmune arthritis)
• Diabetes
• Gout
• Athlete's foot
• Onychomycosis (nail fungal infection)

Diagnosis

To diagnose problems related to the anatomical structures in the foot, your healthcare provider or an orthopedic specialist will look at your foot to look for signs of swelling, deformity, skin growth, or misalignment.

They will review your symptoms and medical history and ask you to walk around to look for abnormalities in your gait (referred to as a gait analysis).

Imaging tests are often central to the diagnosis and can include:

• X-ray: This standard imaging test involves low-level radiation and is suitable for detecting things like bone fractures, dislocations, or arthritis damage.
• Computed tomography (CT): This imaging technology combines multiple X-rays to create a more three-dimensional representation of the foot structure.
• Magnetic resonance imaging (MRI): This imaging technique uses a powerful magnet and radio waves to create highly detailed images without radiation. It is especially good at imaging soft tissues.

Treatment

The treatment for a foot problem will depend on the underlying cause.

Foot pain from any cause can often be relieved with over-the-counter painkillers such as Tylenol (acetaminophen), Advil (ibuprofen), or Aleve (naproxen).

More severe cases may require steroid injections to reduce joint inflammation or prescription pain relievers like Celebrex (celecoxib) to relieve chronic arthritis pain.

For foot problems caused by anatomical deformities, foot orthotics (inserts worn inside the shoes) can help compensate for these problems and reduce pain. Standard versions are available in pharmacies, but often a doctor will order custom-made orthotics or custom-fitted shoes.

Physical therapy can improve the strength and flexibility of the feet and ankles. Sometimes conditions like a displaced fracture, bunions, or hammertoe will require surgery if they are causing severe pain or disability.

Summary

The foot is a complex structure comprised of bones, joints, muscles, ligaments, and tendons. It is vulnerable to injury both from trauma and overuse, as well as diseases and infections. Among some of the more common structural foot problems are bunions, claw toes, flat feet, hammertoes, heel spurs, mallet toes, metatarsalgia, Morton's neuroma, and plantar fasciitis.

The diagnosis of a structural foot problem may involve a physical exam, a review of your symptoms and medical history, a gait analysis, and an imaging test such as an X-ray, CT scan, or MRI scan.

The treatment can vary based on the condition but may involve over-the-counter or prescription painkillers, foot orthotics, custom-fitted shoes, physical therapy, or surgery.