The causes can be traced back to both the nervous and cardiovascular systems. Symptoms such as tingling, numbness or paresthesias should never be under estimated, especially if other problems are also present, e.g. paresis, lack of orientation and headaches.

The most common causes of upper limb numbness are:

• degeneration or fatigue of the spine due to being in a position that puts pressure on the nerves, mainly the cervical region
• heart diseases, especially if the numbness involves the left arm and is accompanied by a characteristic retrosternal pain, and the pain does not subside after changing position; this can even be a symptom of a heart attack and professional medical help should always be sought in the event of such symptoms
• disorders of the cerebral vasculature, stroke, if numbness of the arm and leg on the same side occurs at the same time, as in the case of a heart attack, medical help should be sought immediately
• malnutrition or malabsorption of vitamins and minerals, in addition to the numbness, increased irritability, restlessness and palpitations can be observed
• neurological diseases such as multiple sclerosis, epilepsy or Parkinson's disease