Why would my hands, arms and fingers go numb?

Brain, nerve, blood. Sensation is such a complicated process that there are many possible reasons. Static numbness may represent a process such as stroke, ms, or polyneuropathy, while variable numbness can be due to compression/inflammation of the spine, spinal roots, nerves in the arm, or compromise of the blood flow to any of these regions. Your pcp and/or a neurologist can help with the search!