Tied and knotted very well , A lovely present I sit atop that will not fell

This is my one hundredth consecutive day posting a riddle! You have one for solving, and possibly one for creating. Joe DiMaggio had a fifty six game one for hitting. You might have one in your hair.

I am a map of every vessel, bone, and vein, The blueprint of your body, from your toes up to your brain. I am the science of the structure, the location of every part, The name for the study of your lungs and your heart.

I can fill a room but take up no space. I am the feather’s burden, yet the sun’s face.

I could be a place warm and dry to sleep, so long as you don't mind having to burrow your way in, or getting poked and scratched all night. I could be a plate of crispy onions! I can even simply refer to a messy situation, although I would rather you didn't put a needle in me, thanks.