What can cause numbness and blood rushing to hands?

Several causes.: Arm and hand numbness is usually related to a problem with the nerves. There can be a pinch on the nerve in the wrist (carpal tunnel syndrome) or a pinch on the nerves as they come down into the arm from the neck (radiculopathy). The sensation of blood rushing to the hands may be related to the numbness. A general practitioner or neurologist will be able to discuss this further with you.