Can a thumb injury lead to numbness in your upper arm?

No. Numbness in the upper arm is not related to your injury, it is most likely from a pinched nerve in the neck. I would recommend you see an orthopedic surgeon or a neurologist.

Related Questions

Can having a thumb injury also cause numbness in that upper arm?

Unlikely. All though injuries to the hand fingers and thumb can cause localized numbness, it is unlikely for a thumb injury to cause numbness in the upper arm. If symptoms persist, see your doctor or hand specialists for an evaluation. Read more...
A thumb injury. May ne associated with local nerve issues but is unlilkey to cause upper arm numbness. Howevert if the mechanism of injury was a fall or a torquing injury to the hand, other unrelated injuries can occur. If the onset of both issues occurred at the same time be sure that both items, the thumb and the upper arm are checked. Read more...

Numbness in left arm and thumb?

Considrr. Might be carpal tunnel or even C-6 radicular problem. Testing can give answer. Read more...

What can cause pain along the length of my arm and thumb/finger numbness?

Cervical spine disea. Problem in the neck (cervical spine disc ?C5/c6) could do it ulnar nerve entrapment can be the cause an EMG (electromyogram) will settle the diagnosis. Read more...