I like to draw skulls, bones, muscles etc. It's some of the best practice I can think of. I have a variety of skulls and bones around in the studio. Some that I bought, some that I found in my wanderings. Coyotes, deer, wild dogs, cattle. Even squirrels and lizards. Bones and skulls are some of the best teachers for an artist. I have a human skull REPLICA that I bought. Had to paint it with oil paint to make it look like bone.
Back in art school we had real skeletons to work from. Maybe I'll post some of my old drawings from school one day.