What is the term for rubbing or friction that results from the skin moving one way and the bone underneath it remaining fixed or moving in the opposite direction?

• A. Shearing
• B. Friction
• C. Abrasion
• D. Sliding

Answer: (A)

Shear is the force at play when the skin moves in one direction while the underlying tissues (and bone) stay in place or move in the opposite direction. This differential movement stretches and can damage deeper tissue layers, which is why it’s a key concept in preventing pressure injuries.

Friction is simply the resistance between two surfaces that rub together, not necessarily involving opposite movement of deeper tissues. Abrasion is the wearing away of the skin’s surface from scraping. Sliding refers to moving across a surface, but the scenario described specifically involves the skin moving differently from what lies underneath, which is what makes shear the correct term.