The subcutis is the deepest layer of the skin. It is also the biggest.
It serves as an isolating agent to preserve body warmth as well as a voluminous barrier protecting, muscle, bones as well as the internal organs.
It is also an energy storage area (lipocytes).
In diseases, this layer is affected in the following conditions (not exhaustive): Polyarteritis Nodosa, Fat Necrosis after injections of anticoagulants, Lipoatrophy in HIV during Tritherapy.
Inflammation of this layer is called hypodermatitis.