Well, I guess that in Greek, if someone is referring to the part of their leg that's near the toes or the very bottom of their foot,they use the word πατούσα (fem., pl οι πατούσες) :Ρ
If you want to be a bit more specific, you've also got κνήμη for shin, γάμπα for calf and μπούτι for thigh. I don't think they're particularly commonly used, though - I've never heard them used in speech (though I should point out I'm some way off being fluent). μπούτι I see used at the meat counter at my local supermarket quite a bit :-)
The scientific term for foot is the Katharevousa term άκρος πους, that is not so usual in modern Greek άκρο πόδι. It is usual the term Dimitra mentioned πατούσα, from the verb πατώ, tread, foot. Generally speaking πόδι, πόδια is referring to leg as a whole. So as you have to say more which part, or can show it or you can add the word κάτω στις πατούσες. There is the term πέλμα, πέλματα, as tread, the specific part of the leg that touches the ground.