PURPOSE: To determine the normal relative length, girth, and nail width of the pediatric thumb with respect to the index finger in children ages 1 through 18 years. METHODS: Measurements of relative thumb length, girth, and nail width were performed on 546 hands in 273 volunteers ages 1 through 18 years. At least 22 hands were included for each age group. The data were analyzed by age, gender, and hand, with the thumb compared with the index finger for all measurements. RESULTS: The adducted thumb tip reached an average of 70% of the length of the index finger proximal phalanx and 32% of the length of the index finger from the metacarpophalangeal joint to its tip. The thumb girth and nail width as a percentage of corresponding levels of the index finger girth and nail width were 133% and 105%, respectively. Relative thumb size remained constant with no significant difference in length, width, or girth between age groups. CONCLUSIONS: The relative size of the thumb remains constant during growth. These normative data will allow a more objective assessment of thumb size and appearance.
PURPOSE: To determine the normal relative length, girth, and nail width of the pediatric thumb with respect to the index finger in children ages 1 through 18 years. METHODS: Measurements of relative thumb length, girth, and nail width were performed on 546 hands in 273 volunteers ages 1 through 18 years. At least 22 hands were included for each age group. The data were analyzed by age, gender, and hand, with the thumb compared with the index finger for all measurements. RESULTS: The adducted thumb tip reached an average of 70% of the length of the index finger proximal phalanx and 32% of the length of the index finger from the metacarpophalangeal joint to its tip. The thumb girth and nail width as a percentage of corresponding levels of the index finger girth and nail width were 133% and 105%, respectively. Relative thumb size remained constant with no significant difference in length, width, or girth between age groups. CONCLUSIONS: The relative size of the thumb remains constant during growth. These normative data will allow a more objective assessment of thumb size and appearance.