Question

Friction and shear are mechanical forces that contribute to the development of pressure ulcers. Which of the following is an example of shear injury? A. Lying on a firm surface that does not distribute weight B. Resting in a semi-sitting position that allows gradual downward movement C. Rubbing or irritating the skin so that epithelial cells are removed D. Compression of blood vessels that leads to ischemia, inflammation, and tissue necrosis

Short answer

A) Lying on a firm surface that does not distribute weight B) Resting in a semi-sitting position that allows gradual downward movement C) Rubbing or irritating the skin so that epithelial cells are removed D) Compression of blood vessels that leads to ischemia, inflammation, and tissue necrosis Answer: B) Resting in a semi-sitting position that allows gradual downward movement

Step-by-step solution

Understanding Shear Force and Pressure Ulcers

Pressure ulcers, also known as bedsores, are injuries to the skin and underlying tissue resulting from prolonged pressure on the skin. Shear force is a mechanical force that acts parallel to the skin surface, causing deformation and compression of underlying tissue. When tissues are compressed between two opposing forces, such as the skin against a surface and the underlying bone, these shear forces can disrupt blood flow, leading to inflammation, ischemia, and ultimately tissue necrosis. Now that we understand shear force and how it contributes to pressure ulcers, let's analyze the given options:

Option A: Lying on a firm surface that does not distribute weight

This option represents a scenario where pressure is exerted on certain points of the skin due to an uneven weight distribution, which can contribute to the development of pressure ulcers. However, it does not specifically describe a shear injury and the forces acting parallel to the skin surface.

Option B: Resting in a semi-sitting position that allows gradual downward movement

In this scenario, the person's body weight causes pressure on the skin while the person is in a semi-sitting position. The gradual downward movement indicates that there may be forces acting parallel to the skin surface, causing shear forces on the underlying tissue and potential injury. This option seems to be the most related to a shear injury among the choices.

Option C: Rubbing or irritating the skin so that epithelial cells are removed

This option describes friction, another mechanical force that can contribute to pressure ulcers. Friction is the act of rubbing two surfaces against each other, which can damage the skin and make it more vulnerable to pressure ulcers. However, friction is different from shear force and does not directly describe a shear injury.

Option D: Compression of blood vessels that leads to ischemia, inflammation, and tissue necrosis

This option focuses on the consequences of pressure on the skin, such as compression of blood vessels and resulting tissue damage. While it outlines the process of how a pressure ulcer might develop, it does not specifically describe a shear injury or the forces acting parallel to the skin surface.

Conclusion

Based on our understanding of shear force and its contribution to pressure ulcers, the best example of a shear injury among the given options is "Option B: Resting in a semi-sitting position that allows gradual downward movement". This option specifically mentions the gradual downward movement, indicating the presence of shear forces acting on the skin and underlying tissue.