Arch of the foot: why is it needed and what is called flat feet
The human foot is not a flat support, but a complex arched structure of twenty-six bones, held in place by ligaments, plantar fascia, and working muscles. The longitudinal arch goes from the heel to the heads of the metatarsal bones along the inner edge, the transverse arch - across the forefoot. Thanks to these arches, the foot first flattens out with each step, absorbing the impact, and then reassembles into a rigid lever, pushing off from the ground. It is this change of softness and hardness that makes the gait economical. As the arch flattens, some of the shock absorbing work goes higher up—to the ankle, knee, hip, and lower back.
It is important to understand that arch height is not an indicator of health in itself. People with very low arches can run marathons without a single complaint, while those with beautiful high arches often suffer from heel pain and forefoot overload. Therefore, a modern orthopedist does not look at the picture, but at whether the foot is flexible or rigid, whether it hurts, how the shoes wear out, and whether the person can cope with his usual load. The diagnosis of “flat feet” without complaints and without functional impairment in many cases does not require anything at all except an explanation.
- Longitudinal flatfoot - flattening of the inner arch, the foot seems to fall inward
- Transverse flatfoot - widening of the forefoot, often accompanied by deviation of the big toe
- Combined - a combination of both options, the most common type in adults
- Flexible flat feet - the arch is visible when a person stands on his toes or sits, and disappears when supported
- Rigid flatfoot - the arch is absent in any position, the foot is rigid, often painful
- Acquired flat feet - the arch was there and fell over time or after injury
Children's flat feet: why is this the norm until the age of five or six?
A child is born with a flat foot, and this is correct. The space under the future arch is filled with a fat pad, the ligaments are soft, and the muscles have not yet learned to work. When the baby begins to walk, he puts his legs wide, rolls his feet inward and rests on the entire sole - this is the normal mechanics of the first year of independent walking. The arch begins to appear around the age of three and continues to form until the age of seven or eight, and in some children even longer. This is why the footprint of a four-year-old child, which looks eerily flat in the office, most often means absolutely nothing.
Parents should look not at the shape of the print, but at the child’s behavior. A healthy child with a flexible, flat foot runs, jumps, does not complain or ask to be held before his peers. If he is active, mobile and painlessly rises on his toes, he has an arch, it just appears in dynamics. Something else should be alarming: complaints of pain, refusal to walk, lameness, sharp asymmetry between the legs, as well as a foot that does not change shape when the child stands on tiptoes.
- Up to 5–6 years, a flat foot in the absence of pain is a stage of normal development
- Walking barefoot on uneven surfaces: sand, grass, pebbles is the best foot workout.
- Shoes for a child need light, flexible, with heel fixation, and not a rigid “formative” design
- Excess weight is the most underestimated factor: extra pounds put pressure on the still soft arch
- Asymmetry, pain, lameness and stiff feet are a reason to be examined at any age
- A child who cannot stand on his toes by the age of 3–4 should be examined by an orthopedist
A separate topic is the so-called preventive orthopedic shoes for healthy children. The idea that a rigid shank and high arch support “form” the arch is not confirmed: the arch is built by the working muscles, not the external frame. Moreover, overly hard shoes restrict the work of the foot muscles and deprive them of their natural exercise. A healthy child needs shoes that protect against injury and cold, bend in the forefoot and stay on the foot. Everything else is only for specific medical reasons, and not “just in case.”
Flat feet in adults: when the arch begins to fall
If an adult had an arch and then sank, this is not “the same flat feet from childhood.” This is a separate disease, and most often it is caused by failure of the tendon of the tibialis posterior muscle - the main active lift of the arch. This tendon runs behind the inner malleolus and attaches to the bones of the inner edge of the foot. Under the influence of age, excess weight, diabetes, hypertension and constant overload, it gradually stretches, becomes inflamed and ceases to hold the arch. The arch sinks, the heel tilts outward, the forefoot rolls out, and the foot slowly changes shape over months and years.
It is not difficult to suspect this situation if you know where to look. The process is almost always one-sided - one foot looks noticeably flatter than the other. The area behind and below the inner ankle is painful and swollen, not the sole. The shoes on the sore foot are worn down along the inner edge. And most importantly, a person cannot stand on his toes on one sore leg, although on a healthy leg he can do this without effort. If you look at the patient from behind, more toes are visible on the side of the diseased foot than on the healthy side, because the forefoot is turned outward.
- Age over 40 years, more often in women
- Excess body weight and work with prolonged standing
- Diabetes mellitus, arterial hypertension, inflammatory joint diseases
- Previous injuries to the ankle and foot, fractures of the calcaneus
- A sharp increase in workload: new job, moving, weight gain
- Congenital connective tissue weakness and family history
How to examine the foot and what the degrees mean
- Осмотр стоя и при ходьбе: врач оценивает положение пятки сзади, высоту свода под нагрузкой и без неё, износ обуви, объём движений в суставах стопы.
- Тест подъёма на носки — одной ногой и обеими. Если при подъёме на носки свод появляется, а пятка уходит внутрь, стопа гибкая и активный подъёмник свода работает.
- Плантография или компьютерная подометрия — отпечаток стопы под нагрузкой. Метод наглядный и удобен для наблюдения в динамике, но сам по себе не определяет тактику лечения.
- Рентген стоп обязательно стоя, с нагрузкой, в боковой и прямой проекции. Только под весом тела видно, насколько на самом деле опустился свод.
- Измерение углов на снимке: высоты и угла продольного свода, положения костей переднего отдела. По этим величинам и определяют степень.
- МРТ или ультразвук — при подозрении на повреждение сухожилия задней большеберцовой мышцы, разрыв подошвенной фасции или воспалительное поражение суставов.
The degree of flatfoot is determined by the angles and arch height measured on an x-ray, and not by the appearance of the print. But even here it is important not to overestimate the figure. The grade describes the shape, not the feeling: a person with severe flattening may have no complaints, while a patient with a moderate change may suffer from pain due to overuse of the forefoot. Separately, they look at the picture to see if there are any signs of arthrosis of the tarsal joints, because it is arthrosis, and not the flat foot itself, that often becomes a source of persistent pain.
Insoles, exercises and surgery: what really works
Orthotics are a useful tool, but they are not universal. They do not rebuild the arch and do not “cure” flat feet: their task is to redistribute the pressure, relieve the painful area and support the foot in a more advantageous position while recovery is underway. Hence the simple rule: insoles are needed by those who have complaints or clearly defined mechanical overload, and are not needed by those whose flat feet do not hurt or interfere with them. Buying expensive custom insoles for an asymptomatic child or adult is, unfortunately, the most common way to waste money without benefit.
- Insoles are justified for foot, heel or calf pain associated with overuse
- Justified in case of incompetence of the tibialis posterior tendon - support for the inner edge and heel is needed here
- Justified for diabetes and decreased sensitivity of the feet - for the prevention of ulcers
- Justified when there is a pronounced difference in leg length and after injuries
- Not needed for a healthy child with a flexible, painless flat foot
- Not needed by an adult without complaint, just because the print is “flat”
What always works and for free is strengthening muscles. Calf raises, balancing on one leg, working the short muscles of the foot, stretching the calf muscles and Achilles tendon. The latter is especially important: a shortened calf muscle pulls the heel up and causes the arch to sink with every step, so stretching often helps more than any insole. The second most important factor is weight: losing body weight relieves the load on the foot more effectively than any orthopedic design. Surgery is considered when pain persists despite full conservative treatment, when the deformity has become severe, or when arthrosis has developed. The scope of the intervention depends on the stage: from tendon restoration and moving the fulcrum of the heel bone to fixing the joints with a rigid foot.
Flat feet and military service
The topic of fitness for military service is surrounded by myths almost more than the disease itself. There is a widespread belief that flat feet automatically exempt you from conscription. This is not so: the decision is made by a military medical commission, and it is based not on words or on a foot print, but on objective measurements - radiographs of the feet taken while standing, calculating the angles and height of the arch, as well as the presence or absence of arthrosis of the foot joints and functional disorders. Mild degrees of flattening of the arch, as a rule, do not lead to a limitation of suitability.
- The decision is made by the military medical commission, and not by the attending physician and not by the conscript himself.
- The main document is an x-ray of the feet under load, and not a plantogram or an examination report
- The combination of the degree of flattening of the arch with signs of arthrosis and pain is taken into account
- Wearing insoles, buying shoes and treatment before the commission do not affect the decision
- The assessment is carried out on both feet, the symmetry of changes is also important
- The commission usually reviews previously issued conclusions and old photographs.