Foot Anatomy and Causes of Pain (2024)

The foot is a complex structure made up of 28 bones, 33 joints, 19 muscles, over 100 tendons and ligaments, and more than 200,000 different nerve endings. These work together to allow you to walk, run, maintain balance, absorb impact, and bear upper body weight.

The foot is also vulnerable to injury, including traumatic and repetitive use injuries, as well as diseases and disorders like arthritis, infections, bunions, and plantar fasciitis. These conditions can not only lead to pain but also to significant loss of mobility and quality of life.

Problems with your feet may require diagnosis and treatment by different specialists, most commonly a foot specialist (podiatrist) or a bone and joint specialist (orthopedist). Other specialists may be involved depending on the underlying cause.

Bones of the Foot

The foot has three parts: theforefoot, midfoot, and hindfoot. There are 28 bones in each foot, categorized according to their location.

Forefoot

The forefoot is comprised of 21 bones:

  • Phalanges: These are the toes bones. There are a total of 14 phalanges per foot: two for the big toe and three for each of the other four toes.
  • Metatarsal bones: These are five long bones that extend from the base of each toe to the midfoot. The first metatarsal leading to the big toe plays an important role in forward movement. The second, third, and fourth metatarsals provide stability.
  • Sesamoid bones: These two pea-shaped bones are embedded into a tendon below the first metatarsal on the bottom of the foot. Their job is to stabilize and reduce stress on the tendon.

Midfoot

The midfoot is made up of five of seven tarsal bones that help form the arch of the foot. These five bones are collectively called distal tarsal bones ("distal" meaning further away from the center of the body).

The bones of the midfoot conform to the variable surfaces as you move, absorbing shock as you land from a jump and lift a heavy object.

The midfoot bones are comprised of the following:

  • Navicular bone: This is a C-shaped bone that fits into the heel which articulates the five other distal tarsal bones.
  • Cuboid bone: This is a cube-shaped bone situated next to the navicular bone that is immovable and provides stability to the arch of the foot.
  • Cuneiform bones: These are three highly mobile bones (medial, intermediate, and lateral) that make up the actual arch of the foot.

Hindfoot

There are only two bones of the hindfoot, known collectively as the proximal tarsal bones ("proximal" meaning nearer to the center of the body). These are responsible for transmitting the entire weight of the entire body to the foot.

The proximal tarsal bones are comprised of the following:

  • Calcaneus: This is commonly known as the heel bone.
  • Talus: This bone sits between the calcaneus and the two bones of the lower leg, called thetibiaandfibula.

Joints of the Foot

Joints are the part of the foot where two bones come together. Joints are covered with cartilage and contain lubricating fluids which help the bones glide smoothly during movement. In all, there are 33 joints in each foot.

Forefoot

Your big toe has two joints:

  • Metatarsophalangealjoint: This is the joint situated at the base of the big toe.
  • Interphalangealjoint: This is the joint nearest the tip of the big toe.

The other four toes have one additional joint:

  • Metatarsophalangeal joint: This is the joint situated at the base of the smaller toes.
  • Proximal interphalangeal joint: This is the middle joint of the smaller toes.
  • Distal phalangeal joint: This is the joint situated nearest the tip of the smaller toes.

Midfoot

The midfoot has two major joints and many minor ones. These are collectively known as:

  • Tarsometatarsal joints: Also called the Lisfranc joints, these connect the tarsal and metatarsal bones and provide stability to the arch.
  • Naviculocuneiform joints: These connect the navicular and cuneiform bones, enabling gliding and rotational movement along with flexion and extension of the forefoot.

Hindfoot

The hindfoot contains two major joints:

  • Subtalar joint: This connects the calcaneus and talus and assists with dorsiflexion (bending of the foot laterally upward) and plantar flexion (bending of the foot laterally downward).
  • Transverse tarsal joint: This connects the midfoot to the hindfoot and helps you turn your foot inward (inversion) and outward (eversion).

Muscles of the Foot

The 19 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:This muscle supports the arch of the foot.
  • Tibialis anterior:This muscle aids with inversion and dorsiflexion.
  • Peroneus longus: This muscle is responsible for inversion and dorsiflexion.
  • Peroneus brevis:This muscle is responsible for eversion and plantar flexion.
  • Extensors:These muscles raise the toes when stepping.
  • Flexors:These muscles stabilize the toes and curl them under

Tendons of the Foot

Tendonsare connective tissues that attach muscles to bones. Three major tendons help with plantar flexion and dorsiflexion:

  • Achilles tendon:This runs from the calf muscle to the heel. It is the strongest and largest tendon in the body, making it possible to run, jump, climb stairs, and stand on your toes.
  • Tibialisposterior:This 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, enabling dorsiflexion.

Ligaments of the Foot

Ligaments are connective tissues that connect bone to bone. There are over 30 in each foot, some of the most important of which include:

  • Plantar fascia: This is the longest ligament 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 connects the calcaneus to the talus. Its role is to support the head of the talus.
  • Calcaneocuboid: This connects the calcaneus to the tarsal bones. It helps the plantar fascia support the arch of the foot.

Nerves of the Foot

The foot has over 200,000 nerves that send and receive signals from the brain to enable motor function (movement) and sensations (such as temperature, pressure, and pain).

Major nerves of the foot include:

  • Peroneal nerve: This provides sensations and motor function to the part of the forefoot.
  • Saphenous nerve: This provides sensations and motor function to parts of the midfoot.
  • Tibial nerve: This provides sensations and motor function to the sole and hindfoot.

Each of these nerves, in turn, has numerous branches with different names that service different parts of the foot.

Common Foot Problems

The average person has walked about 75,000 miles by the time they are 50 years old. Given how many moving parts the foot has, it makes sense that it's vulnerable to injury or overuse.

At the same time, there are diseases and disorders that can affect the bones, joints, connective tissues, and nerves of the foot, causing pain and a loss of mobility.

Foot Anatomy and Causes of Pain (1)

Achilles Tendonitis

Achilles tendonitis is an inflammatory injury of the Achilles tendon. It most commonly affects runners and people who play sports like tennis which require lots of starts, stops, and turns.

Untreated tendonitis can lead to the chronic breakdown of the tendon, called Achilles tendinosis. This can weaken it to an extent where the tendon can partially or completely tear, known as an Achilles rupture.

Athlete's Foot

Athlete's foot is a common fungal infection that is highly contagious. It is easily spread, mainly from moist surfaces like locker room floors and showers. If the fungal gets in and under the toenail, it can cause toenail fungus, also known as onychomycosis.

Arthritis

Osteoarthritis (OA), sometimes referred to as "wear-and-tear arthritis," is the aging-related degeneration of joint cartilage that leads to joint pain, stiffness, joint deformity, and the progressive loss of mobility.

In the foot, the small joints of the toes and ankles are most likely to be affected. Obesity can increase a person's risk of foot OA.

Bone Fractures

A bone fracture of the foot, also called a fractured foot, is a common injury often resulting from a sports injury, a car crash, a heavy object dropped on the foot, a misstep, or a fall from a great height. Fractures can range from tiny cracks to a break that penetrates the skin. Around one of every 10 bone fractures occur in the foot.

Bunions

Abunionis 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 get misaligned, often from wearing shoes that don't fit or that squeeze the toes together tightly.

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

Claw Toe

A claw toe is a deformity of the foot where the toe bends downward from the middle joints. Sometimes, it will even curl under the foot entirely.Callouses or cornswill commonly form on top of the claw toe. Ifa cornputs pressure on nerves in the foot, it can also cause pain.

Flat Feet

Pes planus(flat feet) is when the arc of the foot straightens out. It may spread so completely that the entire sole touches 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 something you’re born with (congenital) but it’s often related to age or an injury. Between 20% and 30% of people have some degree of flat-footedness.

Gout

Gout, also known as gouty arthritis, is an inflammatory form of arthritis caused by the accumulation of uric acid crystals in a joint. Gout symptoms occur in episodes, causing extreme pain, swelling, and redness in usually one joint only. The big toes are most commonly affected.

Gout can flare up when you eat foods rich in an organic compound called purine, which the body converts into uric acid. Symptoms may persist for a week or more. Recurrence is common.

Heel Spurs

The calcaneus (heel) is vulnerable to injury as it is tasked with bearing most of the weight of this body. This, along with an imbalanced gait and faulty foot mechanics, can lead to bony overgrowthscalled heel spurs.

Heel spurs, also known as calcaneal spurs, can cause severe pain when standing or walking. They are most common in people with plantar fasciitis, flat feet, or high arches.

Mallet Toe

If you have a mallet toe, the joint in the middle of the toe becomes permanently bent and points downward. Mallet toes develop when there is an imbalance in the muscles, tendons, or ligaments that hold the bones straight.

Like with bunions and hammertoes, a mallet toe often happens if you’re wearing ill-fitting shoes. However, it can also be caused by trauma or some diseases.

Metatarsalgia

Metatarsalgiais pain under the ball of the foot. It’s often caused by pressure from high-heeled shoes or from conditions like arthritis, nerve compression, fractures, or tears in ligaments that support the ball of the foot.

Peripheral Neuropathy

Peripheral neuropathy is nerve pain caused by damage to the outer coating of nerve cells, called myelin. The damage can cause tingling, prickly, burning, or pins-and-needles sensations ranging from mild to severe. The feet are most commonly affected; walking or standing can make symptoms worse.

Peripheral neuropathy can be caused by any number of things that directly or indirectly damage myeline, including diabetes, HIV, alcoholism, autoimmune disease, back injury, heavy metal poisoning, and certain drugs.

Morton's Neuroma

Morton’s neuroma is a common foot problem where compression on a nerve in the ball of the foot causes burning, tingling, and pain near the third and fourth toes. It can make you feel like you have a pebble in your shoe or on a fold in your sock. Wearing high heels is a common cause of Morton’s neuroma.

Plantar Fasciitis

Plantar fasciitis is caused by microtears in the thick fibrous tissue on the underside of the foot. It’s usually related to overstretching. Symptoms of plantar fasciitis include pain in the heel and arch that is often worse in the mornings. Plantar fasciitis is common in distance walkers or runners.

Sprains and Strains

A sprain is a partial tear of a ligament, while a strain is a partial tear of a tendon or muscle. The ankle is a common site of a sprain, typically caused when you twist your ankle during sports or a fall. Foot strains, by contrast, are due to overuse, most often in people with Achilles tendonitis and other types of foot tendonitis.

Diagnosis and Treatment

To diagnose problems with the parts of the foot, a healthcare provider or a foot specialist will look at your feet for signs of swelling, deformity, skin growth, or misalignment.

The provider may feel your foot to check for lumps and bumps, and move it around to see if it causes you discomfort. They will want to watch you walk around to see if there are any issues with the way you move (gait analysis).

Imaging studies commonly used to look for structural problems or injuries include:

  • X-ray: This standard imaging test uses low-level radiation to take pictures. It can pick up conditions 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 of soft tissues like muscles and ligaments.

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

Pain may be treated with over-the-counter painkillers such as Tylenol (acetaminophen) or Advil (ibuprofen). Severe or chronic conditions like arthritis may require steroid injections or prescription pain relievers like Celebrex (celecoxib). Nerve pain may benefit from drugs like gabapentin.

For foot problems caused by anatomical deformities, special inserts may be worn inside your shoes (called orthotics) to compensate for the problems and reduce pain. Physical therapycan help improve the strength and flexibility of the feet and ankles.

Conditions like fractures, bunions, or hammertoe may sometimes requiresurgery.

Summary

The foot is a complex part of the body that is made up of many bones, joints, muscles, ligaments, and tendons. It can easily be injured, develop diseases, or get infections. Bunions, claw toes, flat feet, hammertoes, heel spurs, mallet toes, metatarsalgia, Morton's neuroma, and plantar fasciitis are a few examples of foot problems that commonly cause pain.

A structural foot problem can be diagnosed with 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 for foot pain is based on the condition but can involve OTC or prescription painkillers, orthotics, custom-fitted shoes, physical therapy, or surgery.

Foot Anatomy and Causes of Pain (2024)
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