I feel a little weird about doing this because you're obviously a much better artist than I, but when it comes to critiques I find them hard to resist especially when it's on pieces that look so good already. I may not be an artist or an anatomy expert but I am a man with access to MS Paint at work and an eye for things which appear out of place. Please feel free to ignore any comments you don't find useful.
Here is my take on it.
Legend:
Blue = Looks good
Green = Looks good even though it's a little exaggerated
Red = Looks a little out of place
The left leg: This thigh bone appears to be a little unnatural. I'm not quite sure how to connect it to the skeleton. The knee and the butt don't seem to agree on a direction to face.
Collarbone & Neck: With the "facing left, looking right" pose this looks like a pretty tricky spot. I think the left shoulder is just too far forward. This in turn makes the left arm biceps look a little too large. The neck just doesn't fit on the spine the way that it seems (to me) like it should.
Face: The face is great, but I can't help but feel it's squished too far to the left of the drawing (to the right of the face.) The right eye looks fine but if it was me I would rotate the left eye a touch clockwise then move both the left eye and the nose a little more towards that empty real estate on the face. The mouth might be better a little to the right as well; and dare I suggest it, rotated a little counterclockwise.
I hope that helps in some small way... *scurries away*
