American Academy of Professional Coders (AAPC) Practice Exam

What lies directly underneath the dermis?

1. Superficial fascia

2. Subcutaneous layer

3. Muscle tissue

4. Keratin tissue

The correct answer is: Subcutaneous layer

The subcutaneous layer, also known as the hypodermis, is located directly beneath the dermis of the skin. This layer is primarily composed of adipose tissue and connective tissue, which serves essential functions such as cushioning the underlying structures, insulating the body, and allowing for mobility of the skin over the muscles and bones. Additionally, the subcutaneous layer plays a critical role in thermoregulation and energy storage due to the fat cells it contains. This layer is not only a supporting tissue but also contains larger blood vessels and nerves that branch into the dermis, linking the skin to the underlying structures of the body. The other options, such as superficial fascia and muscle tissue, are not precisely located directly beneath the dermis. While the superficial fascia can be seen as a layer that includes the subcutaneous tissue, it does not specifically refer to the distinct layer that directly follows the dermis. Muscle tissue is typically located even deeper, beneath the subcutaneous layer. Keratin tissue, on the other hand, is found in the outermost part of the epidermis, playing a role in providing protection, rather than being a layer beneath the dermis. Thus, the subcutaneous layer accurately describes the structure directly underneath the dermis.