What is the medical term for the layer of tissue under the skin that can become infected?

The correct answer, subcutaneous tissue, refers to the layer of tissue located beneath the skin's surface. This layer consists primarily of fat and connective tissue, which serves as a cushion for the body, provides insulation, and helps in the storage of energy. When infections occur, they often affect this layer, which can lead to conditions such as cellulitis.

Although the hypodermis is another term used to describe this same layer, it is less commonly referred to in clinical settings compared to subcutaneous tissue. While the dermal layer contributes to the skin's structure and function, it is the subcutaneous tissue that is particularly associated with infections due to its composition and location. The term "fatty layer" can describe the composition of the subcutaneous tissue, but it does not encompass the full range of connective tissues found there. Thus, subcutaneous tissue is the most accurate term when referring specifically to the tissue layer that can become infected.