Which of the following is not a factor in pressure injury development?

• A. External pressure
• B. Friction and shear
• C. Microclimate
• D. Adequate nutrition

Answer: (D)

Pressure injury development depends on tissue tolerance under mechanical and environmental stress. External pressure directly compresses capillaries, leading to ischemia and tissue damage if sustained. Friction and shear damage the skin and deeper tissues, especially when sliding movements pull against an already stressed area. The microclimate—moisture, temperature, and humidity at the skin-surface interface—can macerate skin and weaken its defenses, increasing susceptibility. Adequate nutrition, while crucial for healing and prevention, does not cause a pressure injury; poor nutrition lowers tissue tolerance and raises risk, so good nutrition is protective rather than a factor in development.