QUOTE(nutter @ Jul 10 2007, 03:49 PM)

I've just been going through grade 8 Viola scales with my teacher, and have noticed that when doing 3 octave scales and going into silly positions (:-D) like 7th/8th, I find it really difficult to keep my fingers in the square position they usually have and my 4th finger almost bends the wrong way! I don't know if it's because I'm not bringing my hand/thumb/wrist enough or anything like that, but I get stabbing pains in my wrist...
Playing the viola should not be painful - well, not to the player anyway.

If you are getting pain, that shows there is a problem in your position: it's probably a symptom of tension - and no wonder.
Try this:
Hold out your left arm straight out in front of you, fingers slightly parted, palm up. Now bend the elbow and wrist towards you so that your fingertips fall onto your left shoulder, a bit like a crab. Got that?
Stand the fingers on their tips. Now press down hard with your little finger onto your shoulder. Making sure your whole arm remains completely relaxed all the time, exert all the pressure you can. How are you doing?
Is this a normal position for the human body? - No, it's clearly barmy. The little fiddle is barmy enough: a great big viola is stark raving bonkers. My point is that the whole position is totally unnatural: we therefore have to a) build muscle; b) increase flexibility; c) cheat if possible.
Build muscle by exercising the LH pinkie (do you know that thing of putting the LH fingers on the RH wrist?). To increase flexibility, look at your whole position: is it too tense? Too curled up? Are your fingers gripping the neck like a vice? Is your chin clamped rigidly down on the rest? Move the instrument around - up down, front, side - till you get maximum comfort. Remember it's OK to swing the instrument about depending on what you're doing with it. Get in the habit of taking your chin off the rest when you shift position upwards and only bear down when you shift down.
Is your shoulder rest right for you? Take it off and try playing without. Take off the chinrest and try without that too. Then put them back and see if you're happy. I'll bet you won't be!
Now play in 7th position. How is it? Is the air a bit thin up there? Damn right: if you'd wanted to play all those notes you'd have taken up the violin...