The deepest layer
Under the middle layer is the hypodermis (hy-po-DER-mis). Hypo means under, so its name means under the dermis.
It's made mostly of fat cells, with stretchy threads and bigger blood vessels and nerves running through it.
Doctors also call it the subcutaneous (sub-kyoo-TAY-nee-us) layer, which means the layer under the skin.
A warm, soft blanket
Fat is a great blanket. It keeps body heat from leaking out, so you stay warm on cold days.
It's a cushion too. When you bump into a table or land on your bottom, the cushion layer helps soak up the bump and protect what's inside.
Your body also stores energy in fat, like a pantry for later. When you run, play and grow, your body can use some of it.
Fat even helps your body hold on to some vitamins it needs.
The anchor
The cushion layer ties your skin to the muscles and bones below. It holds on firmly, but loosely enough that your skin can slide a little when you move.
Gently pinch the skin on your arm and wiggle it. It slides over the muscle. That's the cushion layer letting it move.
Every body is different
The cushion layer is thicker in some places, like your bottom and belly, and very thin in others, like your eyelids.
Everybody's cushion layer is different, just like everybody's height is different. Bodies come in lots of shapes and sizes, and all of them are good bodies.
Babies have plenty of padding that helps keep them warm. That's part of why babies are so cuddly!
Fat isn't something bad. Every body needs it to stay healthy.