The Hypodermis (Subcutaneous Tissue)

Subcutaneous tissue, which is also known as the hypodermis, is the innermost layer of skin. It’s made up of fat and connective tissues that house larger blood vessels and nerves, and it acts as an insulator to help regulate body temperature.

The thickness of this subcutaneous layer varies throughout the body and also from person to person.

Subcutaneous Tissue Composition

The skin is composed of three layers: the epidermis, the dermis, and subcutaneous tissue. There are several structures and specialised cells that exist within subcutaneous tissue, including:

• Collagen and elastin fibres (these attach the dermis to muscles and bones)
• Fat cells
• Blood vessels
• Sebaceous glands
• Nerve endings
• Hair follicle roots

The hypodermis is largely composed of adipose tissue (fat tissue), which is made up of adipocytes, or fat cells. The amount of adipose tissue varies throughout the body. It is thickest in the buttocks, the palms of the hands, and the soles of the feet.

The size of adipocytes is determined by an individual’s nutritional habits. Generally speaking, a person who maintains a healthy diet and exercise habits has smaller adipocytes and is less likely to be overweight.

The location and thickness of subcutaneous tissue differ by gender. Men tend to accumulate more around the abdomen and the shoulders, while women tend to accumulate it around the thighs, the hips, and the buttocks.