c. Third-Degree Burn (Full Thickness Burn). Third-degree burns (figure
3-3)are also known as full-thickness burns because they involve the full thickness of the
epidermis and the dermis. The burns may look yellow-brown, dark red, charred, or
white and translucent. Those with red-colored areas will not blanch. The nerves in the
deeper layers of the dermis have been destroyed; therefore, unlike the first- and
second-degree burns, there is no pain or sensation in the burned areas. The skin is
dry, firm, and leathery. The burn has caused the skin to lose its normal elasticity, thus
restricting movement. A third-degree burn on a large part of the chest wall can limit
lung expansion. A third-degree burn around an arm or a leg can constrict blood flow.
These burns usually heal with scars or require skin grafts to heal. Unless the body
surface burned is small, a third-degree casualty requires hospitalization.
Figure 3-3. Third-degree burn.
A burn that involves muscle or bone as well as subcutaneous tissue is
sometimes classified as 4th-degree burn. Electrical burns can damage
muscle or bone as the current travels through the body.
Those areas of thermal injury that are waxy-white, soft and pliable, yet
nonpainful formerly were regarded as full-thickness injuries, but are really
deep, partial-thickness burns. They frequently heal without the need for
grafting if protected from infection. Charring with thermal injury of
subcutaneous and deeper tissues is infrequent, but may occur in an
unconscious victim, in individuals sustaining high voltage electric injury, in
persons trapped by burning debris, or occupants of a burning vehicle.