stratum corneum: Definition, Uses, and Clinical Overview
The stratum corneum is the outermost layer of the epidermis (the surface part of the skin). It is made of flattened, dead skin cells (corneocytes) held together by skin lipids, forming a barrier. It helps keep water in and irritants, microbes, and allergens out. In cosmetic and reconstructive care, it matters because many treatments work by interacting with or passing through this layer.