The Achilles' reflex or triceps surea reflex is a reflex. He belongs to the group of so-called self-reflexes and describes the reaction of the body in one fell swoop on the Achilles tendon. After this stroke, a stimulus is transmitted to the body, causing the ankle to be stretched.

What is the Achilles' reflex?

The Achilles tendon reflex belongs to the group of so-called self-reflexes and describes the reaction of the body to a stroke on the Achilles tendon.

Achilles tendon or Tendo musculi tricipitis sureae is the strongest tendon in the human body and connects the calf muscles, which is also called the triceps surea muscle, with the heel.

These calf muscles consist of three muscle groups, the two calf muscles (gastrocnemius muscle) and the soleus muscle. The length of this string is about 20 to 25cm. The calf muscles control the calf muscles. As a result, movements such as putting on the foot similar to a ballerina when standing on tiptoe, or twisting the foot outwards, can be created.

The Achilles tendon reflex is triggered by a slight blow on the Achilles tendon. A stimulus signal is transmitted via afferent nerve fibers. Afferent nerve fibers are those nerve fibers that transmit incoming signals, in this case the impact on the Achilles' vision, which has taken place from the outside, to the respective destination in the body.

In this case, the afferent nerve is the tibial nerve. He directs the signal to the spinal cord. There, the incoming signal is passed on to the efferent nerve fibers. These nerve fibers transmit the signal to the outside. This happens in the case of the Achilles tendon reflex also by the Nervus tibialis. The incoming signal of the efferent nerve fibers produces a contraction of the triceps aurea muscle, ie the calf musculature. This will stretch the ankle. This entire process is also described as reflex arc.

Function & Task

The Achilles tendon reflex is just one of several reflexes of the human body. He belongs to the group of self-reflexes and often serves to protect the body from damage. The self-reflex is a reflex in which a reaction of the organ concerned to a stimulus is resolved, which means that the reaction takes place exactly where the stimulus has arrived. In the case of extraneous reflections, the reaction takes place at a location other than that of the stimulus input.

It introduces a stimulus from afferent nerve fibers to the spinal cord and then travels back through efferent nerve fibers and the affected muscle to trigger a response from the muscle. In addition to the Achilles tendon reflex, there are a few more, such as the abdominal skin reflex. If there is a blow to the abdominal wall, it will immediately lead to a contraction and thus to a hardening of the abdominal wall. This protects the internal organs from damage from external shocks.

Another self-reflex is the toe flexor reflex. This is also called Rossolimo reflex and describes the reaction to a hit on the toe berries. In response, the toes are flexed. This reflex is usually present only in newborns and indicates a possible disease of the nervous system or the motor system.

A well-known self-reflex is the adductor reflex. This is a reflex that is triggered by the impact on the adductor tendons at the knee joint. It comes to the knocking out of the affected leg. The reflexes should thus protect certain areas such as the internal organs of man, but also, for example, against hot or sharp objects or from falling, which could cause damage.

Diseases & complaints

Another reason for a defective reflex arc is damage to the spinal cord or the nerve fibers which transmit the signals. The Achilles tendon reflex is passed by afferent nerve fibers across the spinal cord and the efferent nerve fibers. These then pass on the signal to the calf muscle. If this signal transmission is disturbed, this may be due to poor signal transmission, ie to defects in nerve fibers or in the spinal cord. This may prevent the signal from being transmitted from the afferent nerve fibers through the spinal cord to the efferent nerve fibers.

Damage to the spinal cord can have various causes. Possible is a trauma of the spinal cord, that is, the damage to the spinal cord caused by violence such as in a car accident.

In addition, a defective Achilles tendon reflex can also indicate a herniated disc, in which the intervertebral discs between the vertebrae are damaged and lose their damping effect.

Also, a defective Achilles tendon reflex may indicate polio, which is also known as polio. Polio is caused by poliovirus and causes paralysis due to infection of the nerve cells and spinal cord.

In addition, a non-functioning Achilles tendon reflex may also indicate neurosyphilis. These are damage to the nerves caused by untreated syphilis. This disease was common in the 18th century, but it is not common nowadays.

  • Food 
  • body processes 
  • drug 
  • medicinal plants 
  • pregnancy 
  • Top