Skin
Skin (Integumentary system)
Cutis (Integumentum commune)
- Origin
- Largest organ of the human body (~1.5-2.0 m² surface area), completely enclosing the body exterior
- Insertion
- Composed of epidermis (stratified squamous keratinized epithelium), dermis (collagen/elastin connective tissue matrix housing vessels, nerves, hair follicles, sebaceous and sweat glands), and subcutaneous tissue (hypodermis)
- Function
- Barrier protection against pathogens and dehydration, thermoregulation (cutaneous vasodilation and sweating), tactile/temperature/pain sensation, metabolic vitamin D synthesis, and fluid homeostasis
- Innervation
- Segmental somatic sensory dermatomes and sympathetic sudomotor/vasomotor fibers
- Movement & chain
- Elastic compliance along Langer's lines of skin tension
- Palpation
- Assessed by skin turgor (hydration), capillary refill time (<2 seconds), temperature, and lesion palpation
- Clinical
- Cutaneous malignancies (melanoma evaluated via ABCDE criteria, basal cell carcinoma, squamous cell carcinoma), thermal burns (depth 1st-4th degree; Wallace Rule of Nines and Parkland fluid resuscitation formula), pressure ulcers (NPUAP stages 1-4).
- Segmental innervation
- All spinal dermatomes C2-S5
- In clinical practice
- Pressure injury prevention (Q2H repositioning, air-suspension mattresses), wound bed preparation and staging, acute burn management (Parkland formula: 4 mL/kg/%TBSA over 24 hours), ABCDE skin cancer surveillance
- Region in the model
- Skin