Its much like the pirate chick's 'blue matter' surrounding her. Felt it looked boring with out it so I kept it. I actually filled it in with this colour, outside the lines and all first. All the colours are digital.
that left leg looks perfect man. Except for the top of the thy (spelling?), theres a little value change there that indicates an elivation change in the muscle, that I dont think is there... But then again I dont have any anatomy book in front of me to look at so I cant be 100% on that. But dude, awesome work
The elevation change on the thigh is the rectus femoris. They are generally more visible on peoples with built muscles. I might have painted it in too dark making it seem more elevated than normal.
Thanks for the comments!