Ever since humans rose above apes and found their way to walking upright, the human foot has possessed a high degree of complexity and function. The foot consists of the tarsus, the five toes, the metatarsus, and the plantar fascia located there. On the latter are receptors that function as a sense of touch. Touch, pressure, pain or temperature are perceived particularly intensively there, even more so than on the five toes. This is a tactile perception that is part of the sense of touch.
What is the sole of the foot?
The sole of the foot forms the entire lower surface of the foot. The bony base is formed by metatarsal bones. It has a surface sensitivity there, which serves to protect the body. This quick perception of changes and touch is possible due to the mechanoreceptors in the skin. Meissner, Vater-Pacini and Ruffini corpuscles and Merkel cells conduct the information via nerve fibers towards the central nervous system. Because of the many nerve endings located in the sole of the foot, people are often ticklish on their feet. In turn, the pain and thermoreceptors are responsible for pain and temperature changes. They are mediated by class C afferents through the nerve endings. If there is a disturbance or damage to these nerves, anesthesia or paresthesia occurs. In addition to the state of insensibility and the state of insensibility, there is also hypersensitivity, which can lead to painful sensations. This is then referred to as tactile defense. The skin reacts to received stimuli through this defense.
Anatomy and structure
The sole of the foot is divided in biology into heel, outer edge of the foot, in the area of the longitudinal arch and the ball of the foot. All these areas can be seen in a footprint in the sand. The footprint can be used to make medical diagnoses, such as whether someone has a flat foot or not. Contact with the ground is not normally made over the entire sole of the foot. In a healthy foot, the inner edge of the foot does not rest in the area of the longitudinal arch. The relief of the sole of the foot has a strong heel ball in the rear area, a ball of the foot with a small toe ball and big toe ball in the front area. Between the soft tissue protrusions lies the concave arch of the foot. The sole of the foot has a substructure that consists of fatty bodies, but is also stable enough to prevent people from slipping as soon as they move. These fat bodies absorb shocks and have a cushioning effect. Through this cushioning, the musculature, skeleton and other anatomical features cannot be felt. The exception is the metatarsal heads of the rays in the middle. Underneath the entire skin of the sole of the foot lies a fibrous plate called the plantar aponeurosis. The term “planta” is the Latin term for sole of the foot. The foot skeleton, musculature, skin and plantar aponeurosis are connected by fibers and form a functional unit.
Function and tasks
In the past, shoe size was determined by a pedoscope. This was used in shoe stores to look through the foot in the shoes. In orthopedics, the foot is examined with the help of a podoscope. This device can be used to diagnose foot damage, holding anomalies or general weaknesses. Through digital pedography, documentation and visualization of the pressure load can be made, which both facilitates the diagnosis and allows for the necessary therapy. This captures stress points and the person’s foot reaction forces dynamically and statically. For this purpose, the patient is placed on a glass platform that has a mirror and a scanning system so that a foot pressure analysis can be made. The measurement results can be used to plan therapies for correct movement patterns. Through the mirror, in turn, the patient can visually check his own foot and adjust it to the given movement pattern. On the sole of the foot there are also special acupressure points that can be massaged. This form of therapy belongs to the eastern healing methods, which stimulates the self-healing of the body through a foot reflexology massage, causes relaxation and serves a promotion of the entire blood circulation. The eastern healing method is based on energy meridians in the foot, which can be stimulated and should lead to an energy boost. Likewise, pain is relieved or cramps are eliminated in this way. Acupressure is also said to help against bladder problems, loss of appetite or hemorrhoids.
Diseases
Since the feet are almost constantly used and subjected to high stress, pain on the sole of the foot occurs more frequently. These can also lead to serious diseases or inflammations and require therapeutic help. The pain in the sole of the foot is rarely accompanied by injuries, but rather expresses itself through a painful tingling sensation in the foot or a flat pulling pain. Likewise there are punctual pressure pains, which can occur, and thus make information about the cause of such complaints possible. These can be, for example, vascular diseases, fractures, torn ligaments or sprains. Gout, rheumatic diseases, arthrosis or osteoporosis also lead to plantar pain. The high pressure load leads to circulation pain and affects the nerves and nerve endings. Discomfort results from pinching off the nerve pathways in the section between the sole of the foot and the central nervous system. This sends a distress signal to the brain, which manifests itself as a severe pulling or tingling sensation in the foot. Accompanying symptoms include low back pain or numbness in the legs. Pressure pain in the heel bone, in turn, is usually an inflammation of the plantar aponeurosis. In this case, the entire tendon plate of the foot is affected. The pain radiates to the metatarsophalangeal joints of the toes. Malalignment of the feet also causes an improper distribution of body weight and can lead to pain.
