The dermis, as a layer, makes up the bulk of the skin and is usually thickest on the back and the back of the neck. The dermis protects the body from mechanical injury, binds and stores water, maintains temperature and carries nerves to detect sensation and feeling. Fat is a soft, shock-absorbing barrier that acts as a conduit for the passage of nerves and blood vessels. Subcutaneous tissue is also an energy storage device. The sebaceous glands of the hair follicle are said to arise in the subcutaneous layer.
Sebaceous glands are in high concentration on the face and scalp.
There are no sebaceous glands on the palms or soles. If you require further information on the structure and function of the skin, please seek a good dermatologic textbook, such as Fitzpatrick or Rook.