Training of the feet, utilizing foot gymnastics and going barefoot on varying terrain, can facilitate the formation of arches during childhood, with a developed arch occurring for most by the age of four to six years. Ligament laxity is also among the factors known to be associated with flat feet. One medical study in India with a large sample size of children who had grown up wearing shoes and others going barefoot found that the longitudinal arches of the bare-footers were generally strongest and highest as a group, and that flat feet were less common in children who had grown up wearing sandals or slippers than among those who had worn closed-toe shoes. Focusing on the influence of footwear on the prevalence of pes planus, the cross-sectional study performed on children noted that wearing shoes throughout early childhood can be detrimental to the development of a normal or a high medial longitudinal arch. The vulnerability for flat foot among shoe-wearing children increases if the child has an associated ligament laxity condition. The results of the study suggest that children be encouraged to play barefooted on various surfaces of terrain and that slippers and sandals are less harmful compared to closed-toe shoes. It appeared that closed-toe shoes greatly inhibited the development of the arch of the foot more so than slippers or sandals. This conclusion may be a result of the notion that intrinsic muscle activity of the arch is required to prevent slippers and sandals from falling off the child’s foot.

Flat feet can also develop as an adult ("adult acquired flatfoot") due to injury, illness, unusual or prolonged stress to the foot, faulty biomechanics, or as part of the normal aging process. This is most common in women over 40 years of age. Known risk factors include obesity, hypertension and diabetes. Flat feet can also occur in pregnant women as a result of temporary changes, due to increased elastin (elasticity) during pregnancy. However, if developed by adulthood, flat feet generally remain flat permanently.

If a youth or adult appears flatfooted while standing in a full weight bearing position, but an arch appears when the person plantarflexes, or pulls the toes back with the rest of the foot flat on the floor, this condition is called flexible flatfoot. This is not a true collapsed arch, as the medial longitudinal arch is still present and the windlass mechanism still operates; this presentation is actually due to excessive pronation of the foot (rolling inwards), although the term 'flat foot' is still applicable as it is a somewhat generic term. Muscular training of the feet is helpful and will often result in increased arch height regardless of age.

The exact cause is unclear. Proposed factors include wearing overly tight shoes, family history, and rheumatoid arthritis. Some state that footwear only worsens a problem caused by genetics.

Morton's Toe is a minority variant of foot shape. Its recorded prevalence varies in different populations, with estimates from 2.95% to 22%.

Asymptomatic anatomical variations in feet generally do not need treatment.

Conservative treatment for foot pain with Morton's toe may involve exercises or placing a flexible pad under the first toe and metatarsal; an early version of the latter treatment was once patented by Dudley Joy Morton. Restoring the Morton’s toe to normal function with proprioceptive orthotics can help alleviate numerous problems of the feet such as metatarsalgia, hammer toes, bunions, Morton's neuroma, plantar fasciitis, and general fatigue of the feet. Rare cases of disabling pain are sometimes treated surgically.

The bump itself is partly due to the swollen bursal sac or an osseous (bony) anomaly on the metatarsophalangeal joint. The larger part of the bump is a normal part of the head of the first metatarsal bone that has tilted sideways to stick out at its distal (far) end.

Bunions are commonly associated with a deviated position of the big toe toward the second toe, and the deviation in the angle between the first and second metatarsal bones of the foot. The small sesamoid bones found beneath the first metatarsal (which help the flexor tendon bend the big toe downwards) may also become deviated over time as the first metatarsal bone drifts away from its normal position. Osteoarthritis of the first metatarsophalangeal joint, diminished and/or altered range of motion, and discomfort with pressure applied to the bump or with motion of the joint, may all accompany bunion development. Atop of the first metatarsal head either medially or dorso-medially, there can also arise a bursa that when inflamed (bursitis), can be the most painful aspect of the process.

Hammer toe most frequently results from wearing poorly fitting shoes that can force the toe into a bent position, such as excessively high heels or shoes that are too short or narrow for the foot. Having the toes bent for long periods of time can cause the muscles in them to shorten, resulting in the hammer toe deformity. This is often found in conjunction with bunions or other foot problems (e.g., a bunion can force the big toe to turn inward and push the other toes). It can also be caused by muscle, nerve, or joint damage resulting from conditions such as osteoarthritis, rheumatoid arthritis, stroke, Charcot–Marie–Tooth disease, complex regional pain syndrome or diabetes. Hammer toe can also be found in Friedreich's ataxia (GAA trinucleotide repeat).

Turf toe is named from the injury being associated with playing sports on rigid surfaces such as artificial turf and is a fairly common injury among professional American football players. Often, the injury occurs when someone or something falls on the back of the calf while that leg's knee and tips of the toes are touching the ground. The toe is hyperextended and thus the joint is injured. Additionally, athletic shoes with very flexible soles combined with cleats that "grab" the turf will cause overextension of the big toe. This can occur on the lesser toes as well. It has also been observed in sports beyond American football, including soccer, basketball, rugby, volleyball, and tae kwon do. This is a primary reason why many athletes prefer natural grass to turf, because it is softer.

In many cases, conservative treatment consisting of physical therapy and new shoes with soft, spacious toe boxes is enough to resolve the condition, while in more severe or longstanding cases Hammertoe Surgery may be necessary to correct the deformity. The patient's doctor may also prescribe some toe exercises that can be done at home to stretch and strengthen the muscles. For example, the individual can gently stretch the toes manually, or use the toes to pick things up off the floor. While watching television or reading, one can put a towel flat under the feet and use the toes to crumple it. The doctor can also prescribe a brace that pushes down on the toes to force them to stretch out their muscles.

In humans, excessive forces caused by sudden bending upwards of the big toe, high heels, or a stumble can contribute to sesamoiditis. Once the sesamoid bone is injured it can be very difficult to cure, because every time you walk you put additional pressure on the sesamoid bone. Treatment in humans consists of anti-inflammatory medication, cortisone injections, strapping to immobilize the big toe, and orthotics with special accommodations to keep pressure off the affected bone.

In horses, sesamoiditis is generally caused by excess stress on the fetlock joint. Conformation that promotes sesamoiditis include long pasterns, or horses with long toes and low heels.

Pigeon toe (also known as metatarsus varus, metatarsus adductus, in-toe gait, intoeing or false clubfoot) is a condition which causes the toes to point inward when walking. It is most common in infants and children under two years of age and, when not the result of simple muscle weakness, normally arises from underlying conditions, such as a twisted shin bone or an excessive anteversion (femoral head is more than 15° from the angle of torsion) resulting in the twisting of the thigh bone when the front part of a person's foot is turned in.

Severe cases are considered a form of clubfoot.

A metatarsophalangeal joint sprain is an injury to the connective tissue between the foot and one of the toes. When the big toe is involved, it is known as "turf toe".

Atherosclerotic restriction to the arterial supply in peripheral artery occlusive disease may result in painful arterial ulcers of the ankle and foot, or give rise of gangrene of the toes and foot. Immobility of a person may result in prolonged pressure applied to the heels causing pressure sores.

Impaired venous drainage from the foot in varicose veins may sequentially result in brown haemosiderin discolouration to the ankle and foot, varicose stasis dermatitis and finally venous ulcers.

Other disorders of the foot include osteoarthritis of the joints, peripheral neuropathy and plantar warts.

The tibia or lower leg slightly or severely twists inward when walking or standing.

Working on steep hills, galloping, and jumping all contribute to navicular syndrome, as they place greater stress on the DDF tendons, and may cause overextension of the pastern and coffin joints.

Regular exercise on hard or irregular ground increases concussion on the hoof, thus increasing the risk of navicular syndrome.

It is possible that standing can also increase the chance of navicular disease (such as a horse that spends most of the day in a stall with little turnout, as with some racehorses and show horses). Blood flow to the hoof decreases when the horse is not in motion. The horse is also constantly applying pressure to the navicular bones (which is intermittent as the horse moves).

In the horse it occurs at the horse's fetlock. The sesamoid bones lie behind the bones of the fetlock, at the back of the joint, and help to keep the tendons and ligaments that run between them correctly functioning.

Usually periostitis (new bone growth) occurs along with sesamoiditis, and the suspensory ligament may also be affected. Sesamoiditis results in inflammation, pain, and eventually bone growth.

The most common cause of foot pain is wearing ill fitting shoes. Women often wear tight shoes that are narrow and constrictive, and thus are most prone to foot problems. Tight shoes often cause overcrowding of toes and result in a variety of structural defects. The next most common cause of foot disease is overuse or traumatic injuries.

Toe walking refers to a condition where a person walks on their toes without putting much weight on the heel or any other part of the foot. Toe walking in toddlers is common. These children usually adopt a normal walking pattern as they grow older. If a child continues to walk on their toes past the age of three, they should be evaluated by a doctor.

Toe walking can be caused by different factors. One type of toe walking is also called "habitual" or "idiopathic" toe walking, where the cause is unknown. Other causes include a congenital short Achilles tendon, muscle spasticity (especially as associated with cerebral palsy) and paralytic muscle disease such as Duchenne muscular dystrophy. A congenital shortening of the Achilles tendon can be hereditary, can take place over time as the result of abnormal foot structure which shortens the tendon, or can shorten over time if its full length is not being used. Toe walking is sometimes caused by a bone block located at the ankle which prevents the antagonist movement, dorsiflexion. This cause is often associated with trauma or arthritis. It may also be one way of accommodating a separate condition, foot drop. Persistent toe walking in children has been identified as a potential early sign of autism.

Toe walking has been found to be more prevalent in males than females when tested with very large numbers of children. This study looked for family history of toe walking and the connection to children demonstrating ITW. 64.2% of the subjects with ITW were males showing a relationship between ITW and males. Of 348 subjects with positive family history of toe walking, about 60% had family history on the paternal side showing it may be genetically related to paternal genes. In 30-42% of idiopathic toe walkers, a family link has been observed.

This condition, which occurs in adolescents and adults, can be associated with previous trauma.

The true cause is not known. Most commonly, hallux rigidus is thought to be caused by wear and tear of the first metatarsophalangeal joint.

Horses with a high weight-to-foot-size ratio may have an increased chance of exhibiting symptoms of navicular syndrome, since the relative load on the foot increases. This might explain why the syndrome is seen more frequently in Thoroughbreds, American Quarter Horses, and Warmbloods as opposed to ponies and Arabians.

Metatarsalgia, literally metatarsal pain and colloquially known as a stone bruise, is any painful foot condition affecting the metatarsal region of the foot. This is a common problem that can affect the joints and bones of the metatarsals.

Metatarsalgia is most often localized to the first metatarsal head – the ball of the foot just behind the big toe. There are two small sesamoid bones under the first metatarsal head. The next most frequent site of metatarsal head pain is under the second metatarsal. This can be due to either too short a first metatarsal bone or to "hypermobility of the first ray" – metatarsal bone and medial cuneiform bone behind it – both of which result in excess pressure being transmitted into the second metatarsal head.

Although the condition is degenerative, it can occur in patients who are relatively young, particularly active sports people who have at some time suffered trauma to the joint (turf toe). A notable example is NBA star Shaquille O'Neal who returned to basketball after surgery.

Tailor's bunion, or bunionette, is a condition caused as a result of inflammation of the fifth metatarsal bone at the base of the little toe.

It is mostly similar to a bunion (the same type of ailment affecting the big toe). It is called Tailor's Bunion because in past centuries, tailors sat cross-legged, and this was thought to cause this protrusion on the outside aspect of the foot.

It is usually characterized by inflammation, pain and redness of the little toe.

Often a tailor's bunion is caused by a faulty mechanical structure of the foot. The fifth metatarsal bone starts to protrude outward, while the little toe moves inward. This change in alignment creates an enlargement on the outside of the foot.

Tailor's bunion is easily diagnosed because the protrusion is visually apparent. X-rays may be ordered to help the surgeon find out the severity of the deformity.

Hallux varus, or sandal gap, is a deformity of the great toe joint where the hallux is deviated medially (towards the midline of the body) away from the first metatarsal bone. The hallux usually moves in the transverse plane. Unlike hallux valgus, also known as hallux abducto valgus or bunion, hallux varus is uncommon in the West but it is common in cultures where the population remains unshod.

Studies have been performed to determine the source of the association between toe walking and cerebral palsy patients. One study suggests that the toe walking—sometimes called an equinus gait—associated with cerebral palsy presents with an abnormally short medial and lateral gastrocnemius and soleus—the primary muscles involved in plantarflexion. A separate study found that the gait could be a compensatory movement due to weakened plantarflexion muscles. The study performed clinical studies to determine that a greater plantarflexion force is required for normal heel-to-toe walking than for toe walking. Able bodied children were tasked to perform gaits at different levels of toe walking and the study discovered that their toe walking could not reduce the force to the levels that cerebral palsy patients indicated in their walk. This suggests that cerebral palsy in which an equinus gait is present may be due to abnormally weakened plantarflexion that can only manage toe walking.