Anatomy & Organs

Calf muscles – structure, function & diseases

Calf muscles

The calf musculature in the narrower sense consists of the two-headed calf muscle and the soleus muscle. The main function of the calf muscles is to flex the foot downwards, an extremely important function in walking, running, jumping and other movements.

What characterizes the calf muscles?

Of the large number of muscles in the calf area, only the two-headed calf muscle ( musculus gastrocnemius ) and the soleus muscle ( musculus soleus ) belong to the calf musculature in the narrower sense. Both muscles are often grouped together as the three-headed calf muscle ( musculus triceps surae ). Occasionally the long calf muscle ( musculus plantaris ) is assigned to the musculus triceps surae because it also supports the flexion of the foot downwards. The gastrocnemius muscle in particular gives the calf its typical appearance. The main task is to bend the foot downwards.

In order to be able to fulfill the task, the muscles at the upper end are connected to the lower part of the thigh bone and at the lower end are attached to the heel bone , the calcaneus, via the Achilles tendon . The double-headed calf muscle is a strong skeletal muscle because the forces acting on the ankle joint—and therefore the calcaneus—during running and jumping can be enormous and are transmitted to the muscle by the Achilles tendon.

Anatomy & Structure

The gastrocnemius muscle has two heads at the top, the internal medial head and the lateral lateral head, which are attached to the lower end of the femur on both sides.

At the lower end, the muscle terminates in the Achilles tendon, which is connected to the posterior end of the calcaneus and can, via a strong leverage effect, absorb forces that act on the ankle joint , for example, from a jump , or transmit forces to the ankle joint when a jump is intended.

The soleus muscle lies below the calf muscle and can be felt on the outside under the gastrocnemius muscle. The lower end of the muscle also opens into the Achilles tendon and is therefore connected to the calcaneus. The musculus plantaris, which some authors attribute to the calf muscles, also flows down into the Achilles tendon.

The muscle that runs below the large calf muscles is of little importance in humans, but it also has a vascular-protecting function. The entire calf musculature is innervated by the tibial nerve ( Nervus tibialis ), one of the two main branches of the sciatic nerve ( Nervus ischiadicus ), which originates from the lumbo-sacral nerve network ( Plexus lumbosakralis ).

Function & Tasks

The main function of the calf muscles is to bend the foot or bend the foot downwards and to absorb forces that are 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 towards the buttocks. Another important function is to support the supination – the outward rotation – of the foot.

This involves raising the inner edge of the foot, i.e. the right edge 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 a canting of the foot outwards. If the canting is provoked unprepared by external influences, such as unnoticed bumps or obstacles on the floor, this can cause an overstretching, a “buckling”.

Supination is also assisted by other muscles such as the posterior tibialis and various toe flexors. The functions of the calf muscles described above play an important role in movement sequences in which the forefoot is subjected to static or dynamic loads without the heel being able to support itself on the ground.

This applies not only to activities such as walking, running and jumping, but also to cycling, where the load is not placed on the entire sole of the foot but primarily on the ball of the foot.

Diseases & Ailments

Complaints associated with the calf muscles can originate in the muscles themselves or be caused by the nervous system. The most common and usually harmless form is sore muscles .

It usually occurs within 12 to 24 hours after the muscle in question has been overloaded. It often occurs in the calf muscles after walking downhill on a tarred road for a long time. Another type of complaint that affects the muscle directly is muscle spasms , which manifest themselves in painful muscle contractions lasting up to a minute that cannot be controlled at will.

In simple cases, it is simply a matter of a disturbance in the electrolyte balance , for example due to loss of minerals as a result of heavy sweating. Heavy alcohol consumption and hyperventilation can also cause muscle cramps. In most cases, there is a reduced magnesium level.

So-called symptomatic cramps can also occur, which are caused by other primary diseases. In this context, circulatory disorders , medication (e.g. diuretics, beta blockers) can play a role and should be clarified.

Apart from neuropathies, which can lead to muscle problems, problems caused by “pinched” nerves are particularly common , because the affected motor neurons, which stimulate the muscles to contract or relax, can only transmit signals to a limited extent.

Since 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.

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Hello! I am Lisa Newlon, and I am a medical writer and researcher with over 10 years of experience in the healthcare industry. I have a Master’s degree in Medicine, and my deep understanding of medical terminology, practices, and procedures has made me a trusted source of information in the medical world.