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!!

Good Idea to label the joints and point out where they are on the structures! I think that you need to do away with thinking about the contour of these complex forms and simplify them down to the most basic shape possible. Once you have simplified try to take these simple constructions and make them more true to the structures you are analyzing. The key is to make the shape that best describes the form as simply as possible, so going back to the most primitive forms will help you in this regard. This is my first critique so sorry if it's worded poorly or hard to understand or overcomplicated, hope it helps and keep drawing!!

And some digital hands