Skin is a component of the integumentary system and is regarded as the human body’s biggest organ. The main barrier between the environment and the body is the skin. Skin supplies a defensive line against chemical and physical agents and microbial pathogens. The skin comprises two layers: the dermis (cutis), a deeper layer of connective tissue, and the epidermis, a superficial keratinized stratified squamous epithelium. Based on the dermis and epidermis thickness, the skin could be categorized as thin or thick. The epidermis cells include four different cell types: keratinocytes, Merkel cells, Langerhans cells, and melanocytes. The epidermal derivatives of the skin contain these structures and integumentary products: nails, sebaceous glands, sweat glands, mammary glands, hair follicles, and hair. The deepest layer, the hypodermis, consists mainly of adipose tissue. The subcutaneous tissue, also known as subcutis (syn: hypodermis), is a tissue that varies in thickness depending on the body region and individual, situated between the dermis (syn: cutis) and the underlying bones, muscles, or fasciae. The fascia comprises three main structures: (1) superficial fascia, (2) deep fascia, (3) muscle-related layers: epi-, peri-, and endomysium.