Numbness in Left Thumb?

The median nerve travels through a tunnel within the wrist called the carpal tunnel. The median nerve gives sensation to the palm sides of the thumb, index finger, long finger, and half of the ring finger. Once your carpal bones (8 bones), If these bones are dramatically disturbed it can cause inflammation which can effect your median nerve. The mere movement of carpal bones themselves can also cause your median never to act up. Since you are still having issues I would try taking an inflammatory such as Ibuprofen or aleve or try ice. If that help you know it was just inflammation. If it is still bothersome, contact a doctor since it may be more serious such as a nerve damage (reversible or permanent) or a cyst.