The calf muscles in the strict sense are composed of the two-headed calf muscle and the clod muscle. The main function of the calf muscles is to flex the foot downward, a hugely important function in walking, running, jumping and other movements.
What characterizes the calf muscles?
Of the multitude of muscles in the calf area, only the two-headed calf muscle (Musculus gastrocnemius ) and the clod muscle (Musculus soleus ) are considered calf muscles in the strict sense. Both muscles are often combined as the three-headed calf muscle (Musculus triceps surae ). Occasionally, the long calf muscle (Musculus plantaris ) is also included in the Musculus triceps surae because it also supports downward flexion of the foot. The gastrocnemius muscle in particular gives the calf its typical appearance. Its main task is to bend the foot downward. In order to perform the task, the muscles are connected to the lower part of the femur at the upper end and fused to the calcaneus, the heel bone, at the lower end via the Achilles tendon. The double-headed calf muscle is a strong skeletal muscle because the forces that act on the ankle joint – and therefore on the calcaneus – during running and jumping can be enormous and are transmitted to the muscle by the Achilles tendon.
Anatomy and structure
The gastrocnemius muscle has two heads upward, the inner caput mediale and the lateral caput laterale, which are attached to the lower end of the femur on both sides. At the lower end, the muscle runs out into the Achilles tendon, which is connected to the posterior end of the calcaneus and can absorb forces acting on the ankle joint, for example, through a strong leverage effect, or can transmit forces to the ankle joint if a jump is intended. The soleus muscle lies below the calf muscle and can be felt laterally on the outside under the gastrocnemius muscle. The lower end of the muscle also joins the Achilles tendon and is therefore connected to the calcaneus. The plantaris muscle, which is considered by some authors to be part of the calf muscles, also opens downward into the Achilles tendon. The muscle, which runs below the large calf muscles, is of little importance in humans, but also performs a vasoprotective function. Innervated throughout the calf muscles is the tibial nerve, one of the two main branches of the sciatic nerve (sciatic nerve), which arises from the lumbo-sacral nerve plexus.
Function and Tasks
The main function of the calf muscles is to flex the foot or angle the foot downward and absorb forces transmitted from the calcaneus to the calf muscles via the Achilles tendon. This is always the case when the foot is loaded without the heel being able to support itself on the ground. In another function, the gastrocnemius muscle supports the flexion of the knee, or the lifting of the lower leg toward the buttocks. Another important function is to support supination – outward rotation – of the foot. It involves elevation of the inner edge of the foot, i.e. the right edge of the foot in the case of the left foot and vice versa. At the same time, the outer edge of the foot is lowered. This can also be imagined as an outward tilting of the foot. If the canting is provoked unprepared by external influences, for example by unnoticed unevenness or obstacles on the ground, this can cause overstretching a “twisting”. Supination is also assisted by other muscles such as the posterior tibial muscle and various toe flexors. The functions of the calf muscles described above play an important role in movement sequences in which static or dynamic loads are applied to the forefoot without the heel being able to support itself on the ground. This is true not only in activities such as walking, running and jumping, but also in cycling, where the entire sole of the foot is not loaded, but primarily the ball of the foot.
Diseases and complaints
Complaints associated with the calf muscles can originate from the muscles themselves or be caused by the nervous supply. The most common and usually the most harmless form is muscle soreness. It usually presents itself within 12 to 24 hours after an overload of the muscle in question.It often occurs in the calf muscles after a long walk downhill on a paved road. Another type of complaint that directly affects the muscle is muscle cramps, which manifest themselves in involuntarily uncontrollable painful muscle contractions lasting up to one minute. In simple cases, it is merely a disturbance of the electrolyte balance, for example, due to mineral loss as a result of heavy sweating. Heavy alcohol consumption and hyperventilation can also cause muscle cramps. In most cases, a reduced magnesium level is present. So-called symptomatic cramps can also occur, which are causally related to other primary diseases. In this context, circulatory disorders, medications (e.g. diuretics, beta-blockers) may play a role and should be clarified. Apart from neuropathies, which can lead to muscle complaints, complaints caused by “pinched” nerves are particularly common, because, for example, affected motor neurons, which stimulate the muscles to contract or relax, can only transmit the signals to a limited extent. Because the calf muscles are supplied with nerve impulses by the tibial nerve, its course must be examined for possible interruptions if only the calf muscles are undersupplied with nerves.
