Hyperactivity of the chewing muscles is usually accompanied by hyperactivity of the other muscles of the head and neck. The human body is a highly complex system of interrelated parts. TMJ patients often report trigger points of pain in the neck and shoulders. The combined hyperactivity of these muscles sometimes constricts, or puts pressure on the radial nerves which exit the nervous system at the level of the neck. These nerves supply sensation to the upper limbs. This constriction or tightening on the nerves of the arms may show up as a tingling sensation of the fingers.