Which layer contains the inner cells in the volar area of the epidermis?

The stratum Malpighii is the layer of the epidermis that contains the inner cells, primarily the basal layer and the stratum spinosum. This region is critical because it is where mitosis occurs, and new cells are generated. The basal layer specifically consists of the basal cells that are responsible for producing new keratinocytes, which eventually move up through the layers of the epidermis as they mature, contributing to the skin's outer barrier.

In contrast, the stratum corneum is the outermost layer composed of dead keratinized cells, offering a protective barrier. The dermal papillae are structures located within the dermis that interdigitate with the epidermis to improve the attachment between the two layers, but they do not consist of epidermal cells themselves. Thus, the stratum Malpighii is recognized as the layer housing the vital inner cells of the epidermal structure, vital for the ongoing regeneration and maintenance of skin integrity.