Friction wounds
When surfaces in contact (f.e. bed linen and human skin) move relative to each other, the friction between the two surfaces converts kinetic energy into heat. This heat leads to degradation of the different epidermal layers. The skin becomes warm and irritated and soon a blister or superficial burn will appear.
Friction wounds are frequently seen among persons having spasms or persons with involuntary movements. Also people using prosthesis or wheelchairs often have friction lesions.