ABSTRACT
The skin is the outermost organ of the body. It is a complex membrane comprising of three major layers-epidermis, dermis, and hypodermis. The epidermis is an avascular stratifying layer of epithelial cells that overlies the connective tissue layer, the dermis. The outermost layer of epidermis, the stratum corneum, is primarily responsible for the barrier properties of the skin. The underlying viable epidermis is different from the stratum corneum in being physiologically more akin to other living cellular tissues. The dermis comprises the largest fraction of the skin and is responsible for providing its structural strength. The dermis also provides an environment for nerve and vascular networks and appendages required to support the epidermis. The dermis is also a primary site in which cutaneous inflammation occurs in response to skin injury (1). The blood supply to the dermis is important in the systemic absorption of substances applied to the skin. The epidermis and dermis are supported by an internal layer of adipose tissue, the hypodermis. This layer provides a cushion between the external skin layers and internal structures such as bone and muscle. It also provides an energy source, allows for skin mobility, molds body contours, and insulates the body.
