There are many problems that are found in the upper extremity. These can start in the neck with entrapment of nerves in the spine or in the muscles of the neck. There are many locations in the arm and chest where both blood vessels and nerves can become entrapped. This is one of the reasons that carpal tunnel or hand numbness can be so hard to treat. There are over 5 areas where the nerve can become entrapped not just in the wrist. Many of these conditions are described on the linked pages from here.