Which layer is NOT considered part of the skin?

The hypodermis, also known as the subcutaneous layer, is the layer that is not considered part of the skin. It lies beneath the dermis and primarily consists of loose connective tissue and fat. This layer plays a crucial role in insulation, energy storage, and providing a cushion for underlying structures. Although it is intrinsically related to the skin, serving functions that support it, it is not classified as one of the skin layers.

In contrast, the dermis is the thick inner layer of the skin that contains connective tissue, blood vessels, and nerve endings. The epidermis is the outermost layer of the skin, composed of several sub-layers, which provide a barrier and protection against environmental factors. The stratum corneum is the outermost sub-layer of the epidermis, consisting of dead keratinized cells, which further aids in protecting the underlying layers.

Understanding the anatomical layers of the skin is essential for coding and diagnosing purposes in healthcare settings, especially for conditions or procedures that involve the skin.