You don't always need to get the anatomy correct,
But when your drawing people it's hard to make them look
good without having their anatomy at least close to a
real humans.
Take a look at some cartoon people.
Notice how they have anatomy that is close to what
a real person would have.
And when you break a humans anatomy down it's not that complex.
Th upper arm is about the same length as the lower,
The upper leg is about the same length as the lower.
The body is about two and a half times the height of the head,
and the legs are about one and a half time the lengh of the
body.