Skin shearing is an injury where skin layers and underlying tissues slide past each other, causing damage. It significantly impacts individuals with limited mobility, making understanding its mechanics important for prevention and management.
What Skin Shearing Is
Skin shearing occurs when a mechanical force parallel to the body’s surface causes internal tissue layers to move in opposite directions. For example, if skin stays still while bones and muscles shift, soft tissues stretch and distort, tearing tiny blood vessels and lymphatic structures. This compromises tissue integrity, reducing blood flow, oxygen, and nutrients, leading to cell death and damage. Though the skin’s surface may appear intact, significant underlying damage can occur, making early detection difficult.
Shearing Versus Friction
Shearing and friction are distinct mechanical forces causing skin injury, affecting different tissue layers. Friction occurs when two surfaces rub, damaging superficial skin layers like an abrasion or “rug burn,” primarily affecting the epidermis. In contrast, shearing involves a gliding force where skin stays in place while underlying tissues shift, causing internal distortion. While friction damages the surface, shearing affects deeper layers, stretching and tearing blood vessels and other structures.
Where Shearing Occurs
Skin shearing often occurs when the body moves but the skin stays fixed against a surface, such as sliding down in a bed or chair. Here, bones and deeper tissues move downward due to gravity, while the skin maintains contact, creating opposing forces that stretch and damage tissues. Individuals with limited mobility, including those bedridden, wheelchair users, or with sensory impairment, are susceptible. Bony prominences like the sacrum, heels, and elbows are especially vulnerable due to less skin padding.
Recognizing and Preventing Shearing Injuries
Recognizing shearing injuries is difficult as initial damage occurs beneath the skin. While the skin may appear discolored, bruised, or show blistering, underlying tissue damage is often more extensive. Shearing wounds can also present with an asymmetrical, ragged, or uneven shape, indicating internal tearing.
Preventing shearing involves minimizing forces on the skin. Proper positioning, such as keeping a bed’s head at or below a 30-degree angle, reduces sliding. Using assistive devices like lift sheets or mechanical lifts to move individuals, maintaining skin hydration, and using pressure-redistributing mattresses or cushions also protect vulnerable areas.