The Subcutis (hypodermis)

The primary components of the subcutis, the innermost skin layer, are fat cells (adipocytes) and spongy connective tissue. Within this layer, fat cells are clumped together in cushion-like groups. These clumps are held together by the special collagen fibres called tissue septa or boundaries. Also interspersed throughout the cutis are a multitude of blood vessels.

The subcutis layer of the dermis has three important functions:

• The clumps of fat cells provide a ‘padding’ that acts as a protective shock absorber for the fascia and muscle tissue that lie beneath
• This padding also insulates the body from cold and heat
• Fat cells serve as important storage units for nutrients. When the body needs them, they are transported from the fat cells into the surrounding blood vessels, which carry the nutrients to areas which need them

The number of fat cells contained in the subcutis is not the same in all areas of the body. For example, in the buttocks and soles of the feet, where extra padding and shock absorption is needed, there are many more fat cells than in other areas of the body. In addition, the distribution of fat cells differs between men and women: women tend to store more fat cells in the thighs and hips, whereas men do so in the turso.