This is probably due to an injury of a small nerve branch in the thumb itself. Your chances of this improving with time are better the shorter time duration of the numbness. Are you aware of a recent injury to the thumb? This could be an important clue as to the cause.
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Anthony Bray MD
No the thumb numbness is not related to your sciatica. You may have an entrapment or compression of a small nerve branch most likely near the point at which you have the numbness.
I hope this helps. Further questions are welcome if you have further. Best regards,
No, I would not be alarmed so much with this finding as it is so isolated.
Anthony bray MD