He was nailed....but through the wrists, severing the median nerve (causing unbelievable pain) and providing enough support to hold the body up (they never, ever crucified through the hands).
One other tidbit: when you sever the median nerve, the thumbs fold inward.
On what do you base your statement. There is not one verse in the entire Bible that says Jesus was nailed to anything.
In ancient times the wrist (and a portion of the forearm, IIRC) was considered the “hand.”
I think it has to do with if you spread your fingers out the generally circular outline that would be made by a circle with the thumb and pinky being endpoints of the chord bisecting the center would also include/circumscribe the wrist.