Which of the following is commonly known as the subcutaneous layer of the skin?

• A. Epidermis
• B. Dermis
• C. Hypodermis
• D. Endoderm

Answer: (C)

The subcutaneous layer, known as the hypodermis, is the layer beneath the dermis that many people think of when they hear “under the skin.” It’s primarily made of adipose (fat) tissue and loose connective tissue, which provides insulation, cushioning, and an energy reserve. Its position—below the dermis and between the skin and deeper tissues like muscle—fits the meaning of “subcutaneous.”

In contrast, the epidermis is the outer protective layer of skin, and the dermis is the thicker middle layer that contains blood vessels, nerves, hair follicles, and glands. Endoderm is a primitive embryonic germ layer, not a component of adult skin.