Which layer of the epidermis is found only in thick skin and contains 3-5 layers of clear flat dead keratinocytes?

The stratum lucidum is a specialized layer of the epidermis that is found exclusively in thick skin, such as the palms of the hands and the soles of the feet. This layer comprises 3 to 5 layers of clear, flat, dead keratinocytes that provide an extra barrier to help protect underlying tissues. The keratinocytes in the stratum lucidum are usually flattened and densely packed with keratin, making this layer appear translucent.

This unique composition contributes to the thickness and toughness of the skin in areas subject to high friction and abrasion. The presence of the stratum lucidum is essential for enhancing the durability and protective function of thick skin, differentiating it from thin skin, which lacks this specific layer. Other layers, such as the stratum granulosum, stratum corneum, and stratum spinosum, have distinct roles and cellular compositions that do not involve the characteristics specific to the stratum lucidum, making this layer essential for specialized protection in regions of high wear.