Skin Anatomy PDF

## Skin - Largest organ which forms the external surface of the body - Surface (1.2 to 2.2) m² - Accounts 7% of total body weight in average adult ### Structure | Layer | Details | |---|---| | **Epidermis** | Avascular superficial epithelial layer containing Melanocytes | | **Dermis** | Vascular...

## Skin - Largest organ which forms the external surface of the body - Surface (1.2 to 2.2) m² - Accounts 7% of total body weight in average adult ### Structure | Layer | Details | |---|---| | **Epidermis** | Avascular superficial epithelial layer containing Melanocytes | | **Dermis** | Vascular deep connective tissue layer containing collagen fibers | | **Subcutaneous (Hypo-dermis)** | Includes blood vessels and adipose tissue | * The cells in this layer are melanocytes which contain melanin pigment, which is responsible for the color of the skin. * The epidermis protects the deeper layers from damage by ultraviolet rays. ### Skin Appendages - Nails - Hairs - Sebaceous glands - Sweat glands ## Nails - Protection of finger and toes - Made up of dead cells packed with keratin ### Functions - Absorption of substances applied to it such as creams - Activation of vitamin D by the action of ultraviolet rays - Barrier against microorganisms - Collect information about the external stimuli (heat, cold, touch, pressure, and pain) - Heat exchange between the body and external enviroment - Protection of the underlying soft tissues from external damage ## Cleavage Lines Of Langer - Dermis contains collagen fibers arranged in parallel rows - Langer's lines: The direction of rows in dermis - Circumferential on chest and abdomen (neck & trunk) - Longitudinal along the extremities (head & limbs) ### Clinical Importance - **Incisions made across Langer's lines:** lead to more retraction, wound gapping and prominent scar formation. - **Incisions made parallel to Langer's lines:** lead to less retraction, decrease wound gapping and less scar formation. ## Surface Area Of Skin "Rule Of Nines" - To assess the extent of the area of skin involved in burns - The body is divided into anatomical regions that represent 9% of the total body surface area. | Region | Percentage | |---|---| | Anterior and Posterior head and neck | 9% | | Anterior and Posterior Trunk | 36% | | Anterior and Posterior upper extremities | 18% | | Anterior and Posterior lower extremities | 36% | | Perineum | 1% | **Total: 100%**