Learning anatomy

[umbral glen]

I currently learning the anatomy of a human from a michale hampton book so I attemp to draw a back from a Pinterest picture I try my best with the perspective of the body parts and try to add lines of the bulbs of the muscles from the picture is there anything I can improve on please tell me thank you

[south anchor]

Don't

you want to find understand the muscle structure undernear the skin, so that when you shade you are not shading randomly or fully relying on the reference