Understanding the wound-healing process of the skin requires knowledge of the anatomy of the skin.
- Skin: Cutis = epidermis + dermis [Figure 6].
- Epidermis: Outer layer of skin (0.1-1 mm thick), consists of:
- Stratum corneum (= horny layer).
- Stratum lucidum.
- Stratum spinosum.
- Stratum basale (= stratum germinativum).
- Dermis: Corium (1-2 mm thick).
- Subcutis: Fatty tissue beneath the skin.
Figure 6
The epidermis consists of the ectoderm and does not contain blood vessels. The stratum basale of the epidermis contains keratin-forming cells. They divide in the stratum basale and after 3-4 weeks migrate to the stratum corneum via the stratum spinosum. The most important function of the corneal layer is to protect against fluid loss and invasive bodies.
The dermis originates in the mesoderm and consists of loosely knit connective tissue with collagen, elastin, and reticular fibres. The dermis contains blood vessels, nerve endings, lymphatic vessels, sweat and sebaceous glands, and hair follicles.
The subcutis is the layer of fatty tissue beneath the skin that acts primarily as a storage organ and is involved in heat regulation. It contains blood vessels and sensory nerves for the skin. The term subcutaneous is used rather than subdermal, because it refers to the tissue found under the entire skin (cutis), rather than just the dermis.