Scott Eaton has a great course on facial expressions, but yeah I really wish proko would do a facial anatomy/expressions course or update this course with that information.

Leg Bones Skelley Drawings

You're focusing too much on the contour, try and draw the shapes as simply as you can, like a croquet mallet for the femur - make the forms simple shapes and then you can start blending them into eachother. I would reccomend reading how to draw my scott robertson because I believe you would benefit from gaining a clearer understanding of basic perspective principles. One of my instructors said, the more technically you are trained - the less technically you draw, which basically means that after studying enough, you're going to be able to draw contours that look like they have perspective because you will get a feeling of what is right - and you have the knowledge of construction to help you out of any pitfalls as you draw. Keep drawing and have fun, it's a marathon not a sprint!!