Hi figureofspeech!
I hate it when people who are supposed to <strong>teach us</strong> end up doing quite the opposite!
Did you use a reference image for this? If you did it would be helpful to compare. In the meantime I'll do my best to pinpoint what's a little off, though I can't make any promises that I'm 100% right. Edit again: Herp derp, sorry! I read that this was a life drawing study so obviously there was no image, but my decaffeinated brain didn't register this.
The neck seems unusually long. It stood out to me immediately, but it may not necessarily be too long. This might be because your drawing is missing a proper connection between neck and shoulders. It's like the collarbones are missing. This gives the illusion of the neck being too long, plus it makes it look like it's not connected to the shoulders.
I tried to draw over it roughly to show you what I mean, I won't use this anywhere else other than this topic to help you. Does this look like it makes sense to you? I did this very quickly, sorry for the messiness.
http://i.imgur.com/lADFqfo.png
Edit: Oh dear. Click on it for full size, it seems the forum squished the preview together!