ABSTRACT
Histologic examination of skin reveals relatively cuboidal cells at the base of the
epidermis (1). This is the replicative compartment and occasionally basal cells are
seen in the process of cell division. However, most of the cells in the basal layer
are quiescent and serve to anchor the epidermis onto the basal lamina, which is
a specialized interface between the epidermis and the dermis. Several layers of
cells immediately above the basal layer have a prickly or spiny appearance and are
collectively called the spinous layer. This appearance reflects the shrinkage of cell
bodies away from the many desmosomal plaques in these suprabasal layers.
Above the spinous cells are several layers of cells that contain dark granular
material. The grainy material is composed of several protein components, which
make up the keratohyalin granules. In the uppermost cells within this compartment
there are no nuclei.