Pedant alert!

Palaeoontologists might say we've got 5 digits on each of the four limbs and the palaeoanthropologists reckon we've inherited the opposability of one of them (on each of the anterior limbs) from our primate ancestors, many of whom had (along with some of our extant "cousins") an opposable digit on each posterior limb as well. I don't recall it being distinguished by a name separating it from its mates, though. Curious.

Cheers, Rowan