The stratum corneum plays a pivotal role in the skin barrier function. It consists of tightly packed, dead keratinocytes known as corneocytes, which are surrounded by a lipid matrix. This structure is often described as a "brick and mortar" model: the corneocytes are the bricks, and the lipids are the mortar. This configuration provides a semi-permeable barrier, allowing essential moisture to be retained while preventing the ingress of harmful substances.
