Human Body Surface Area:The human body's total surface area is an important measurement used in various medical calculations, such as determining drug dosages and the volume of intravenous fluids to administer. Over the years, several formulas have been developed to calculate body surface area, resulting in slightly different outcomes. The Mosteller formula, introduced in 1987 in *The New England Journal of Medicine*, is the most widely used today. According to Mosteller's "simplified calculation of body-surface area in metric terms," the body surface area equals the square root of the product of weight in kilograms and height in centimeters, divided by 3600.While the "normal" body surface area is often considered to be 1.7 m², it actually depends on various factors beyond just height and weight, such as age and gender. For instance:- Average body surface area for adult men: 1.9 m²- Average body surface area for adult women: 1.6 m²- Average body surface area for 9-year-old children: 1.07 m²- Average body surface area for 10-year-old children: 1.14 m²- Average body surface area for children aged 12-13 years: 1.33 m²Body surface area is also crucial for other medical assessments. For example, renal function is evaluated using the glomerular filtration rate (GFR), which considers body surface area. Additionally, cardiac output is better approximated when divided by body surface area. Pharmacotherapy dosages are often based on a patient's body surface area, and dosing calculations for maintenance or high-dose treatments also rely on this metric.Reference: Mosteller RD. Simplified calculation of body-surface area. *N Engl J Med* 1987;317:1098.
