Which frostbite degree is characterized by freezing deep to muscle, tendon, and bone?

• A. Freezing deep to muscle, tendon, and bone
• B. Partial thickness skin freezing
• C. Deep skin freezing
• D. Freezing of skin and subdermal plexus

Answer: (A)

Tissue depth of freezing determines frostbite severity, and when the freezing penetrates to muscle, tendon, and bone you’re looking at the most severe form. This deepest injury—fourth-degree frostbite—reflects damage to all the way to the deepest structures, with high risk of tissue loss and poor prognosis. The other descriptions describe progressively less deep involvement, such as injury limited to the skin or dermal layers, which do not reach muscle or bone. Therefore, the description of freezing deep to muscle, tendon, and bone is the correct match.