What is considered the highest layer of the skin?

The highest layer of the skin is the stratum corneum. This layer serves as the outermost barrier of the skin, consisting of dead skin cells that have undergone a process called keratinization. These cells are flat and densely packed with keratin, a protein that provides strength and waterproofing. The stratum corneum plays a crucial role in protecting underlying tissues from environmental factors such as pathogens, UV radiation, and chemical exposure. Additionally, it prevents excessive water loss, helping to maintain hydration in the skin. As the top layer, the stratum corneum is essential for the overall health and functionality of the skin, making it a significant focus in various skin treatments and care routines.

In contrast, the other layers—stratum granulosum, stratum lucidum, and stratum spinosum—are located beneath the stratum corneum and play different roles in the skin's structure and function. These layers contribute to the formation and regeneration of skin cells but do not serve as the primary protective barrier that the stratum corneum provides.