Wound Care Certified Certification (WCC) Practice Exam

What type of force causes undermining and tunneling in a pressure injury?

1. Frictio

2. Shear

3. Compression

4. Tension

The correct answer is: Shear

Shear is the correct choice because it refers to the forces that occur when layers of tissue slide over each other. In the context of a pressure injury, shear forces can result from the weight of the body pressing down on a surface while other layers of tissue, such as the skin above and the subcutaneous layers below, are pulled in different directions—often due to movement. This sliding motion disrupts the structural integrity of the tissues and can create undermining (where the wound extends under the edges of the skin) and tunneling (a deeper channel-like opening under the skin). Understanding shear is crucial for wound care professionals, as it highlights the importance of proper positioning and the use of support surfaces that can help reduce these forces on patients at risk for pressure injuries. It emphasizes the need for measures such as proper elevating of limbs and using turn sheets to minimize these damaging forces.