What distinguishes the stratum lucidum from other epidermal layers?

The stratum lucidum is a unique layer of the epidermis that is primarily characterized by its composition of dead keratinocytes. This layer is found only in specific areas of thick skin, such as the palms of the hands and the soles of the feet, which are subject to greater wear and tear. The presence of the stratum lucidum contributes to the thickness and durability of the skin in these regions, providing an extra layer of protection. This is essential in areas that experience significant friction and pressure.

In contrast, other layers of the epidermis, such as the stratum corneum or stratum granulosum, contain living cells or are involved in other functions, including forming a barrier against water loss and pathogens. The distinction of the stratum lucidum lies in its lack of living cells and its role in forming thicker skin, which is crucial for areas prone to damage.