Introduction
The foot is a so-called supporting organ of the body. Since the feet are important for carrying the body weight and for locomotion, they are supported by a tight ligamentous apparatus. Bones, joints, ligaments, tendons and muscles can be injured or inflamed and thus cause pain. If structures on the inside are affected, the pain can also be localized there. The pain is often noticed when standing, walking or in certain foot positions, but can also occur at rest.
Causes for pain on the inside of the foot
The causes of pain on the inside of the foot can be many and varied. Pain on the inside of the foot often occurs due to overstrain – for example after sports. Even severe overweight can damage foot structures and cause pain.
However, uncorrected malpositioning of the foot or the foot-leg axis can also cause the foot to be incorrectly loaded. Incorrect footwear can cause pain. For example, shoes that are too tight can cause pain.
Continued incorrect loading can affect different structures of the foot in different ways. The tendon of the posterior tibialis muscle pulls on the back of the lower leg over the back of the inner ankle to the underside of the foot. If the tendon becomes inflamed due to an injury or degeneration, pain is usually felt on the inside of the foot.
The pain can increase when the sole of the foot is passively rotated outwards. The pain can also be felt more strongly when walking – especially barefoot. In most cases, the inflammation of the tendon is caused by overloading during sports.
The overloading is often caused by overexertion when jogging or jumping. A flat foot can also promote the development of tibialis posterior tendon inflammation. Furthermore, the constant wearing of high shoes can lead to an inflammation of the tibialis posterior tendon.
The tarsal tunnel syndrome is a damage of the tibial nerve. In tarsal tunnel syndrome, this nerve is constricted at the level of the inner ankle by retaining straps (more precisely: retinaculum musculorum flexorum). Pain occurs at the level of the inner ankle and can radiate into the heel.
In addition, numbness (paresthesia) can occur on the sole of the foot. These can manifest themselves as tingling, numbness or cold and heat sensation disorders. The tarsal tunnel syndrome is often triggered by traumas such as ruptured ligaments, fractures or sprains.
However, the narrowing can also occur after operations on the ankle due to scarring. With the pes valgus, the heel of the lower leg is tilted inwards. Often, the pes valgus occurs with a flat foot, whereby the inner arch of the foot is not rounded, but lies flat on the ground.
In this combination, one then speaks of a buckling-sinking foot. In childhood, the flat foot is physiological (normal), asymptomatic and in most cases grows together spontaneously. However, if the flat foot persists, it can lead to a flat foot (Pes planus), which is an extreme form of the flat foot.
This can develop, among other things, due to overweight, incorrect footwear, but also without an obvious cause. The development of a pes planus in adulthood is usually due to obesity, but can also have other causes, such as injury or defect of the muscle tendon of the posterior tibialis muscle (see paragraph above). Initially, there is often pain behind or below the inner ankle when the foot is bent.
The pain can radiate into the lower leg. In the further course of the disease, the pain can spread to the region of the outer ankle due to additional malpositioning. The calcaneal spur causes the tendons of the muscles that attach to the calcaneus to ossify.
This ossification is often triggered by incorrect loading. Overweight or foot malpositions such as flat feet or hollow feet can also promote heel spurs. In addition, heel spurs frequently occur in jobs that are performed standing or walking.
Plantar fasciitis is a heel spur on the sole of the foot. Plantar fasciitis occurs more frequently in women and those affected are usually over 30 years old. Pain is most common in the morning or during exercise.
Paradoxically, the pain can also improve under heavy strain – e.g. when jogging.Pain is then mainly felt on the inner heel, which can radiate towards the toes. In addition, the inner heel is often painful under pressure. Hallux rigidus is an arthrosis (wear and tear of the joint cartilage) of the metatarsophalangeal joint of the big toe.
Triggers for arthrosis can be previous injuries (e.g. in soccer players), inflammation (gout, rheumatism) or age-related wear and tear. Pain occurs mainly when the foot rolls, which can then radiate from the big toe to the inside of the foot. Standing on tiptoe is also painful.
Os naviculare externum or also Os tibiale externum is a small additional bone on the inside of the scaphoid (Os naviculare) of the foot. The scaphoid forms the arch of the foot and is part of the lower ankle joint. The additional external navicular bone is found in about 10% of the population.
If the additional ankle is large or lies unfavorably, the tendon of the posterior tibial muscle can be affected. This can lead to pain under the inner ankle and on the inside of the edge of the foot. The pain is particularly noticeable when walking. Constant irritation of the tendon can lead to a defect of the tendon. Since this is important in the tension of the foot tendon plate, a weakness (insufficiency) can lead to a flat foot.