PREPARE THYNESELF. It's not easy, but you've reached the "last bit" of anatomy! KEEP AT IT. (This was what studying anatomy of the arms looked like, for me at least. Prolly im just nub).
Attempts at adding them muskles on :'D
HAAAAAALP I haven't even started on the hands yet, still struggling with wrapping my head around the arm groups and whether they get to be seen from the back while wrapping to the front and whatnot. Do the legs get easier?!
Test over some doodles..