hand\arm positions

[luposolitario]

I have noticed that my hands aren't completely facing downwards when I play.
They are slightly rotated towards the 5th finger (the thumb is in higher position than
the 5th). To have them face downwards I must rotate the forearm inwards (it seems
an unnatural and tense position) or move the arm (upper part) outwards. Is one of
this positions right???

(Difficult to explain in English. Is it understandable?)