The lower leg is the part of the leg that is between the knee and the foot. The bony structures are formed by the tibia ( tibia ) and fibula ( fibula ), which in turn are connected by a tight band connection, the membrana interossea cruris . Below the knee there is a tight joint between the tibia and the fibula, an amphiarthrosis, whereas the two lower leg bones are banded above the ankle joint and represent the so-called syndesmosis tibiofibularis . The joint between the upper and lower leg (knee joint) is a hinge joint. It allows movements in the degrees of freedom, extension and flexion, as well as rotation movements to a small extent. The tibial-fibular connections ( talofibular proximal and distal types ) provide only sliding movements as planar joints, but the distal tibial-fibular joint forms the ankle-fork and thus stabilizes the upper ankle joint.
A subdivision of the lower leg muscles is carried out according to the function and position of the muscles in two groups, each with two other subgroups. The forelimb musculature is divided into extensors (Strecker) on the lateral-anterior side and the fibular muscles, which are located in the area of the fibula on the outer side. The lower leg muscles are divided into superficial flexors (flexors), collectively referred to in anatomy as the triceps surae muscle, and into the deep flexor muscles.
The extensors of the lower leg muscles are:
The main function of the tibialis anterior muscle is the elevation of the foot. His tendon is deflected by ligaments of the ankle and ends on the inside of the foot in the middle of the Fußwölbung rather on the back of the foot. Through this approach, the tibialis anterior muscle can lift the foot and especially the foot margin (supination).
The extensor digitorum longus, also known as the "long toe extensor, " causes dorsal extension (pulling up) of the second to fifth toe in the metatarsophalangeal joint and of the foot in the upper ankle joint.
The "long toe extensor " is the extensor hallucis longus, responsible for pulling up the big toe. Depending on the position of the foot, it may also assist inward or outward rotation of the lower ankle.
The fibular muscles include:
The term "long fibula muscle " refers to the peroneus longus muscle . Similar to the tibialis anterior muscle, it starts in the middle of the foot flexion but there on the side of the sole of the foot. His primary task is to stretch his foot towards the floor and turn inwards. The tendon of the peroneus longus muscle also provides stability in the transverse arch due to its transverse profile.
The "short fibular muscle " or the fibularis brevis muscle, like the peroneus longus muscle, provides for plantarflexion, ie for the foot to extend downwards. Its tendon runs in humans in a common tendon sheath with that of the peroneus longus muscle.
The superficial lower leg muscles include:
In the area of the lower leg muscles, the soleus and gastrocnemius muscles work closely together. They are synergists and are summarized in the anatomical terminology as the triceps surae muscle .
The soleus muscle ( soleus muscle ) is mostly covered by the gastrocnemius muscle, which is why it is only visible on the sides of the lower leg. His task is plantarflexion, that is, pulling down the foot towards the sole of the foot. In addition, he is responsible for the elevation of the inner edge of the foot while lowering the outer.
The gastrocnemius muscle, also called the twin calf muscle, gives the human calf its characteristic form. In close cooperation with the soleus muscle, he causes the upper hock to contract the foot ( plantarflexion ), in the lower ankle to elevate the inner margin of the foot ( supination ), and to flex in the knee joint. The gastrocnemius muscle has two muscular heads, called Caput mediale (inner head) and Caput lateral (outer head) according to their position. Both arise at the lower part of the thighbone. The heel bone represents the approach of the two unified muscle bellies. The Achilles tendon is the common tendon of the gastrocnemius muscle and the soleus muscle.
A muscle smaller in size and reduced in size, but still strongly developed in monkeys, is the plantar musculus . Not present in every human being, this muscle radiates into the aponeurosis plantaris, a tendon plate in the area of the sole of the foot. The function of the plantar musculature is almost meaningless in humans. He is only slightly involved in the flexion of the knee and the inward rotation of the lower leg in flexion.
The deep layer of the lower leg muscles include:
The posterior tibial muscle, also known as the posterior tibial muscle, attaches to the biliary and cuneiform bones with its tendon that runs through the so-called tarsal tunnel. Its tasks are the lowering ( plantarflexion ) of the foot and the elevation of the inner foot edge.
The flexor hallucis longus, Latin for long long toe flexor, is the strongest of the deep flexor muscles. Its tendon crosses the tendon of the flexor digitorum longus muscle in the area of the sole of the foot (see below). At this point, the flexor hallucis longus flexes the muscles of the flexor digitorum longus . In addition to flexing the big toe down, the flexor hallucis longus muscle supports plantarflexion.
The "long toe flexor", flexor digitorum longus, bends all toes except the big toe towards the sole of the foot and promotes plantarflexion (flexion towards the sole of the foot) of the foot. His tendon divides into four tendons behind the tarsal tunnel, a canal bounded by bone and connective tissue in the area of the ankle, which finally reaches the individual toes.
Fascia refers to collagenous, fibrous connective tissue that forms joint and organ capsules and also encloses muscles, bones, nerve tracts and blood vessels. The entire lower leg musculature is surrounded by the so-called Fascia cruris . Individual muscle groups are, according to their function, subdivided by further fascia into different compartments and separated from each other. This separation results in functional units that are called muscle lodges in anatomy.
In the lower leg are the following lodges:
The fascia surrounding the muscle tissue causes compression, which can prevent swelling after stress or injury.
The anatomical separation of the individual muscle groups by fascia, however, carries the risk that it comes to injuries to bleeding in the muscle lodges. The compartment syndrome is usually caused by traumas such as fractures or as a result blunt force. Also, surgery or muscular overload, as it can occur in performance and recreational athletes can trigger a compartment syndrome via bleeding or edema.
Due to the reduced elasticity of the fibrous connective tissue of the fascia, the pressure within a muscle compartment can rise sharply, which also compresses vein nerve bundles of the lower leg. This is followed by impairment of blood supply and neuromuscular function. An early symptom is severe pain in the affected limb in conjunction with a feeling of tightness and increasing emotional disturbances such as numbness and tingling. The mobility can sometimes be severely limited. Increasing pressure in the lodge is increasingly hampering venous drainage. With initially preserved arterial blood circulation, a vicious cycle starts, which leads to a further increase in pressure. As a result, the arterial blood circulation ceases with increasing deficiency of the muscles. At this stage, motor deficits and a pulselessness occur in the area after the affected muscle box. Due to the threat of widespread tissue descent, the compartment syndrome is an absolute emergency that needs urgent care.
The treatment of choice in traumatic compartment syndrome is the surgical splitting of the fascia of the affected muscle lobule and adjacent compartments to provide pressure relief. After the swelling, the artificial incision can either be sutured or covered by a skin graft. If the compartment syndrome is not treated in time, it can lead to a massive destruction of the affected muscle tissue, which in extreme cases necessitates an amputation of the extremity.
The tibiasis syndrome, also called medial (medial) or lateral (lateral) tibial ankle syndrome, depending on the localization, is a disease that usually occurs in connection with physical activity. It refers to stress-dependent, dull or stabbing pain on the shin bone edge. Particularly at risk are joggers or athletes who exercise intensively in sports with special stress on the tibial or foot muscles.
Multiple states can trigger the pain. The exact development of the tibial nerve syndrome has not been conclusively clarified. Especially pronation movements of the foot, ie elevation of the lateral margin of the foot with simultaneous reduction of the medial edge of the foot, seem to favor a tibial splenic syndrome. According to current knowledge, the causes are mostly overuse of the musculature, inflammation or injury of the muscle. Overuse can result from a variety of sports. In the foreground, however, are running or ball sports with a quick change of direction, such as football or handball. In the case of untrained persons, intensive training can quickly lead to tibial nerve syndrome. Experienced and well-trained athletes may also suffer from illness as a result of rapid weight gain or a change of footwear.
Often the pain occurs the day after the exercise. If training continues, the training can be painful. In the place of the heavy load of the tibial bone, over time, it can lead to periostitis, for example, of the tibia. Especially hobby athletes tend to push pain on the overuse of the muscles. If there is a suspicion of inflammation of the periosteum, appropriate diagnostics should be initiated immediately by means of imaging techniques (magnetic resonance imaging) and subsequent therapy. Athletes feel particularly stressful, the sometimes long-term impairment in training, which is explained by the slow healing of the disease.
The therapy itself is often unsatisfactory and the possibilities of medicine are sometimes limited. In the foreground is the protection of the affected limb, which usually leads to a rapid improvement of the symptoms, but which can occur again when re-stressed. By local cooling, the disease can be favorably influenced. In case of severe pain, nonsteroidal anti-inflammatory drugs such as ibuprofen® can be pain-relieving. When choosing pads or braces that are worn in the shoe during exercise, the doctor can assist and advise.
The congenital clubfoot, also Pes equinovarus, is a deformity of the child's foot and occurs with a frequency of 1: 1000 births. J
are twice as likely to be affected as girls. The cause of the foot deformity is a disturbance of the balance of the lower leg muscles, in which the plantar flexors, ie flexors of the foot towards the sole of the foot, and supinators, lifters of the middle foot rim, predominate.
The term "clubfoot muscle " also refers to the tibialis posterior muscle, which causes the foot to become supinated and bends towards the sole of the foot. The malposition exists right at birth and is a combination of several deformities. As a rule, an inward rotation of the foot, the forefoot position of the forefoot, equinus, hollow foot and a lateral deviation of the heel come together.
The exact origin of the innate clubfoot is not yet clear.
However, it is believed that the location of the embryo in the uterus is a crucial factor.
Even a reduced amount of amniotic fluid could favor the development of a clubfoot. As a result of a neural tube defect, the defective formation of the embryonic system of the central nervous system, paralysis of the lower leg muscles can occur and thus the formation of a clubfoot. It is also discussed whether a congenital clubfoot can occur as a result of the intake of folic acid antagonists such as Aminopterin ® or Methotrexat ® in the fourth to twelfth week of gestation.
Treatment should be initiated immediately after birth. First, the therapy consists in the fixation of the foot, the so-called retention, which is gradually adjusted to a correct position (redressement). The plaster cast has to be changed regularly, whereby the redressement is continued. At the age of about three months, an operation on the Achilles tendon may be necessary, whereby this is prolonged and the angle between heel and heel bone is corrected.
Other measures may include transplantation of the tibialis anterior muscle, bone corrections or joint stiffness. In order to stretch shortened muscles and to mobilize the joints of the foot, physiotherapeutic procedures should be used at an early stage, since in the long-term it can lead to another deviation in the malposition.