Pollex (noun)
The thumb; the first, or preaxial, digit of the forelimb, corresponding to the hallux in the hind limb. In birds, the pollex is the joint which bears the alula or bastard wing.
Hallux (noun)
The big toe.
Wiktionary
Pollex (noun)
the innermost digit of a forelimb, especially the thumb in primates.
Oxford Dictionary