I refer you to the Wikipedia article on Crucifixion under the section entitled "Nail Placement".
http://en.wikipedia.org/wiki/Crucifixion
There were various methods of crucifixion and nail placement. It was well within normal Roman practice that the nails would have been driven through the palms of the Lord's hands.
Here is a link with information on the more important question of the meaning of the Cross:
I hope you have found this helpful.
God bless,
Mike