Hi,
Thank you for posting your query.
The 
numbness of arms denotes a dysfunction of the nerves in the arms.
We need to exclude a diagnosis of 
carpal tunnel syndrome, where the 
median nerve gets compressed at the level of wrist. The diagnosis can be confirmed by doing nerve conduction studies.
There are good medicines to treat this condition, and hence, there is no need to worry.
I hope my reply has helped you.
I would be pleased to answer, if you have any follow up queries or if you require any further information.     
Best wishes,
Dr Sudhir Kumar MD (Internal Medicine), DM (Neurology)
Senior Consultant Neurologist
Apollo Hospitals, Hyderabad,
For DIRECT QUERY to me:  http://bit.ly/Dr-Sudhir-kumar 
My blog: http://bestneurodoctor.blogspot.com/