Which layer of the skin is referred to as the "horny layer"?

The "horny layer" refers to the outermost layer of the skin, known as the stratum corneum. This layer is composed of dead keratinized cells that serve as a protective barrier. The term "horny layer" comes from the tough, keratin-rich composition of this layer, resembling the horns of certain animals due to its hard, protective characteristics. The stratum corneum plays a crucial role in preventing water loss and protecting underlying layers from environmental damage, pathogens, and chemical exposure.

In contrast, the other layers mentioned do not share the same attributes as the stratum corneum. The stratum germinativum is known for housing proliferative cells responsible for generating new skin cells. The stratum lucidum is a thin, translucent layer found primarily in areas of thick skin, such as the palms and soles, while the stratum granulosum acts as a transitional layer where cells begin to lose their nuclei and form keratin. Each layer has its distinct role in skin health, but the "horny layer" specifically denotes the stratum corneum due to its structural and functional characteristics.