Burns
The most common system of classifying burns categorizes them as first-, second-, or third-degree. Sometimes this is extended to include a fourth or even up to a sixth degree, but most burns are first- to third-degree, with the higher-degree burns typically being used to classify burns post-mortem. The following are brief descriptions of these classes:
First-degree burns are usually limited to redness (erythema), a white plaque and minor pain at the site of injury. These burns only involve the epidermis.
Second-degree burns manifest as erythema with superficial blistering of the skin, and can involve more or less pain depending on the level of nerve involvement. Second-degree burns involve the superficial (papillary) dermis and may also involve the deep (reticular) dermis layer.
Third-degree burns occur when most of the epidermis is lost with damage to underlying ligaments, tendons and muscle. Burn victims will exhibit charring of the skin, and sometimes hard eschars will be present. An eschar is a scab that has separated from the unaffected part of the body. These types of burns are often considered painless, because nerve endings have been destroyed in the burned area. Hair follicles and sweat glands may also be lost due to complete destruction of the dermis. Third degree burns result in scarring and may be fatal if the affected area is significantly large.
Fourth-degree burns damage bone tissue and may result in a condition called compartment syndrome, which threatens the life of the limb.
Fifth-degree burns are burns in which most of the hypodermis is lost, charring and exposing the muscle underneath. Sometimes, fifth-degree burns can be fatal.
Sixth-degree burns, the most severe form, are burn types in which almost all the muscle tissue in the area is destroyed, leaving almost nothing but charred bone. Often, sixth-degree burns are deadly.