The Shroud even shows stains from nail-marks in the WRISTS, not the hands. In Greek the word for hand...includes the forearms. So when the Bible says Jesus had marks on his hands after the resurrection...it doesn’t mean the palms.
Medieval artists though, did not know this, so you ALWAYS see depictions of the crucifixion with nails going through the palms. Testing was done around 1900 with cadavers in France. Without additional support, like tying the arms to the cross, nails in the palms simply (excuse the image) rip out... Physically, nailing a man like that to a cross doesn’t work.
HOWEVER, if nails are (most painfully) put through the wrists, or, in between the radius & ulna bones (in the forearm) a body CAN hang on a cross, and not fall off. And in the wrist area...is exactly where the Shroud shows the nails. Unknown to anyone really, for 1600+ years, since the Romans stopped crucifying people....