Excellent sculpt, vastus medialis may be a little big. 
For me is the good size, but thank you very much for take your time and comment.
Greetings.
an i love this very much awesomastic keep em comin
Thank you!
Holy christ that pencil man is absolutely terrifying. I would watch that horror movie.
As for the figure, the neck is broken and too long. When our necks are held back like that, the back of the neck condenses, causing wrinkling and compression. The front of the neck accordions out sort of like you have, but the adams apple becomes more prominent and the tendons thin out, so that is becomes a C from the side instead of an S.
I believe that the problem is amplified by the fact that you have not given her any shoulder mass. With her arm back like that it would push the mass of muscle forward, so that her shoulder becomes more prominent, not less. This will help balance the length of the neck as well, although that area still needs the major change.
EDIT: did a super quick and crappy paintover, just trying to fix the overall forms and mass. Nothing I could do for the medium or minor shading.
Thank you very much for your appreciations, your right…but this is just a play around with some poses is not a finish work or something.
But i will keep in mind all your tips.
Thanks, greetings.
Muy buen trabajo,