The stratum corneum is a cellular tissue. Its building blocks, the corneocytes, are highly resistant to physical and chemical trauma. The mechanical strength of an individual corneocyte, emanating from its tightly packed keratin bundles and the cross-linked proteins of the cornified envelope, is outstanding. The mechanical resistance of individual corneocytes is mirrored by the pronounced mechanical strength of the entire stratum corneum, implying a strong cell cohesion within the tissue. The corneocytes and their intercellular cohesive structures are prerequisites for the function of the stratum corneum as the physical-chemical barrier between body interior and exterior, serving as an important part of the barrier as well as a backbone for the intercellular barrier lipids.