That fourth claw on Sabertooth is really idiotic. It makes my top three of "Things that makes no sense in the Ultimate Universe".
Where the hell does it retract? At least Wolverine's claw are roughly lined up with his wrist and set between his knuckles.
Sabertooth's claws are line up directly with the knuckle (they go through them?!) and the one lined up with the index clearly has nowhere to go when he sheaths it.
It's just silly. He has one claw too many. Wolverine's claws are firmly in "suspend your disbelief, it's just a comic" territory but Sabertooth has busted through that and is into "Was Millar taking advices from a 5 year old when he made that decision?" territory.
PS : For those who wonder, my list is :
1 - Magneto not catapulting Colossus into space as soon as he saw that the big lump of metal was resisting
2 - Those freakin' claws
3 - Elektra beating the crap out of Spider-Man