The dermis is divided into two layers: papillary and reticular (Fig. 13). The thin papillary dermis is just below the basement membrane and contains loose collagen and fibrocytes. The reticular dermis is relatively thick and contains compact collagen and a few fibrocytes. The reticular dermis includes the origins of the epidermal appendages. Collagen is synthesized by fibrocytes, mainly in the papillary dermis. Skin collagen decreases by 1% per year as patients age (20). Reticulin fibers are found throughout the dermis and are probably immature collagen fibers. Elastic fibers are eosinophilic fibers that extend from the basement membrane into the reticular dermis. Sun damage causes the elastic fibers to thicken and collect in the papillary dermis; these elastic fibers are then referred to as elastotic fibers. Aging causes a disappearance of elastic fibers in the papillary dermis (21).
Was this article helpful?