A Rule of Thumb for Hand Burns: Categorization and Mapping of Proportional Surface Area Involvement.

Hand burns are common and often complex injuries, requiring referral to specialist centers. The patient's thumbprint is a rapid means of accurately assessing hand burn surface area. This study aimed to establish categories and evaluate sites of hand burn surface area in order to facilitate comparison of hand burns. Sixteen burns involving the hand and wrist among 14 patients referred to a burns center were retrospectively categorized by burn mechanism, burn thickness, and hand burn surface area. The burn surface area in the clinical record was compared with that calculated by the thumbprint method and the rule of thumb diagram. Burn surface area in the clinical record was either "1%" or "<1%" in 9 of 16 cases. In contrast, the surface area was <1 thumbprint (T) in six burns, two were between 1 and 5T, three were 5 to 10T, two were 10 to 20T, two were 20 to 50T, and one was greater than 50T. The median thumbprint burn surface area was 1.5T (range 0.20-80T), which corresponds to 0.05% TBSA. The hand areas with the highest burn frequency per unit area were the dorsum of the hand and dorsum of the index finger, with relative sparing of the palm and palmar surface of the digits. Hand burns surface area varies widely, and thumbprint evaluation with categories and mapping allows finer distinction between the surface area proportions and specific sites involved, even in a small series of hand burns.