Behind a numbness in the arms, thighs, feet or face may be due to various causes. Often, a lack of blood flow or a jammed nerve responsible for the complaints. But even serious diseases such as a herniated disc or a stroke can be associated with a feeling of numbness. We will inform you about possible causes and give tips on what you can do to prevent the sensation of numbness.
A numb feeling - medically termed hypesthesia - is caused by a decreased sensitivity of the skin. If such a feeling of numbness is present, the feeling sense is disturbed and it can be passed on this way no or only limited information about external stimuli to the brain. This includes information on heat and cold, touch and pressure, pain and vibration. A complete loss of feeling is called anesthesia.
A loss of sense of feeling occurs especially in the extremities, so a numbness in the fingers, toes, arms and legs is particularly common. In the face or on the trunk, it is rather rare. The numb feeling can occur both on one side and on both sides. Often the numbness is accompanied by an unpleasant tingling sensation.
Numbness: causes and diagnosis
Behind a numbness can be a variety of causes stuck. In some cases, the cause is harmless, but recurrent numbness can also indicate a serious condition. If the feeling of numbness occurs more frequently, a doctor should be consulted. Possible causes of numbness include:
- Circulatory disorders
- Pinched nerves
- Carpal Tunnel Syndrome
- disc prolapse
- Vitamin B12 deficiency
Depending on the cause of the numbness, other symptoms may also occur at the same time, such as pain or motor impairment.
In the diagnosis, it is first of all decisive for the attending physician where, since when and in which situations the numbness sensation occurs, whether it occurs unilaterally or bilaterally and whether it persists since the first onset or disappears on its own. To determine possible damage to the nerves, the doctor checks the reflexes as well as various sensory performances - for example hearing and vision. If there is a first suspicion, further investigations may be necessary.
Circulatory disorders as a cause
At low temperatures in winter, our hands and feet may become too cold and we may have no feeling in them. Due to the cold, the vessels contract and the extremities are less well supplied with blood. Only at warmer temperatures the numbness disappears and the sensation returns - this process is often accompanied by an unpleasant tingling sensation in the fingers and toes.
While cold-related, short-term circulatory disorders are generally harmless, you should consult a doctor immediately if there is a circulatory problem without a cause. Then, serious conditions such as atherosclerosis or Raynaud's disease, which primarily affects the arteries in the fingers and toes, may be behind the numbness sensation. Especially circulatory disorders in the brain as well as in the legs can cause a numb feeling. Circulatory disorders in the heart, however, are more noticeable by a tightness in the chest.
Pinched nerves as a cause
Numbness in the arms, legs, hands and feet, caused by a pinched nerve, has probably been experienced by everyone before: A wrong posture - for example when sitting or lying down - will pinch off a nerve and disrupt the transmission of stimuli.
As a result, the hand or arm feels numb and usually can not be moved at will. Often a sleepy arm or a fallen leg is accompanied by an unpleasant tingling sensation on the skin. As soon as we move the sleeping body part a little bit, the numb feeling usually disappears on its own. If this is not the case or the feeling of numbness occurs more often, there is probably another reason behind the symptoms, which should be clarified by a doctor.
Carpal tunnel syndrome as a cause
If it comes in the fingers to a constantly recurring numbness and an unpleasant tingling, is probably a carpal tunnel syndrome behind the symptoms. The median nerve is narrowed when passing through the carpal canal. The causes of a carpal tunnel syndrome can be diverse, for example include bony malpositions after fractures or tendonitis added. Often, however, no direct cause can be determined. By wearing a special splint, the numbness in the fingers can usually be corrected. If no improvement occurs, an operative treatment takes place.
In addition to a carpal tunnel syndrome, a numbness in the fingers and hands but also arise when other nerves, such as the cervical nerve, are disconnected (Ulnartunnelsyndrom). This syndrome is also referred to as cyclist paralysis, as it is usually caused by the tight grip of the handlebar.
Narrowing of the nerve channels can occur not only on the arms, but also on the legs. Especially a pinched nerve and a related numbness on the thigh occur. This is called inguinal tunnel syndrome (groin tunnel syndrome) or jean disease. It is damaged by overweight, but also by too tight clothing of the thigh skin nerve. Depending on the stage of the syndrome, medical, physical or surgical therapy may be considered.