Stage I: This stage is characterized by a surface reddening of the skin. The skin is unbroken and the wound is superficial. Generally when pressure is relieved off of this area the skin integrity is returned to baseline.
Stage II: This stage is characterized by a blister either broken or unbroken. A partial layer of the skin is now injured. Involvement is no longer superficial.
Stage III: The wound extends through all of the layers of the skin. It is a primary site for a serious infection to occur.
Stage IV: A Stage IV wound extends through the skin and involves underlying muscle, tendons and bone. The diameter of the wound is not as important as the depth. This is very serious and can produce a life threatening infection, especially if not aggressively treated. All of the goals of protecting, cleaning and alleviation of pressure on the area still apply. Nutrition and hydration is now critical. Without adequate nutrition, this wound will not heal.