CLINICAL APPLICATION OF FOUNDATIONAL SCIENCES
The integumentary system is the largest organ in the body and is important to our survival in many ways.* The skin is a membranous barrier between our internal system and the environment and responds to external and internal changes. The examination requires an understanding of the structures and functions of the system. Understanding the healthy and disease states of skin, hair, nails, mucous membranes, circulation, and sensory structures is essential to the examination.
The integumentary system has two major components, the cutaneous membrane (skin) and accessory structures (Figure 4–1). The skin is divided into three layers: the epidermis, the dermis, and the subcutaneous tissue. The accessory structures include the hair, nails, vascular supply, sweat glands, and sebaceous glands. The skin is the site of many complex and dynamic processes, which include being a protective barrier, having immunologic functions for first-line defenses, and functions of melanin production, vitamin D synthesis, sensation, temperature regulation, protection from trauma, and aesthetics.1
Anatomy of the skin. (Reproduced with permission from Mescher AL. Junqueira’s Basic Histology: Text and Atlas, 16th ed. New York, NY: McGraw Hill; 2021. Figure 18–11.)
High-Yield Terms to Learn
|Capillary refill || |
Press down on one of the patient’s nails until it pales. Release the nail and observe for the pink color to return. The normal color should return in less than 3 seconds.
Note: Capillary refill can be affected by room and body temperature, vasoconstriction from smoking, or peripheral edema.
|Clubbing || |
Normal concave nail bases will create a small, diamond-shaped space when the nails of the index fingers of each hand are placed together. Clubbed fingers are convex at the bases and will touch without leaving a space.
Note: Finger clubbing, a sign of chronic tissue hypoxia, occurs when the angle between the fingernail and where the nail enters the skin increases (Schamroth sign).
|Cyanosis || |
Dark bluish or purplish discoloration of the integument and mucous membranes.
Note: This may indicate hypoxia or hematologic pathology.
|Dermatitis ||Inflammation of the skin. |
|Exudate ||Also known as drainage, exudate is a liquid produced by the body in response to tissue damage. |
|Hyperthermia || |
Note: It may indicate localized or systemic infection, inflammation, or thermal injury; hyperthyroidism or fever is generalized.
|Hypertrophic scar ||A raised scar that stays within the boundaries of the burn wound; characteristically red, raised, and firm. |
|Hypothermia || |
Note: This may indicate arterial insufficiency or shock.
|Jaundice || |
Yellowish discoloration of skin and sclera.
Note: This may indicate liver disease or hemolytic pathology.
|Keloid scar ||A raised scar that extends beyond the boundaries of the original burn wound; red, raised, firm. |
|Pruritus ||Itching. |
|Total body surface area (TBSA) ||Used to estimate the total fluid and caloric requirements and is a predictor of mortality. |