Background: The breast meridian is a central axis in breast surgery design, essential for procedures such as breast reduction and mastopexy. Traditional methods of marking the breast meridian rely on subjective surgeon perspectives, often leading to postoperative asymmetry and inconsistent outcomes. This study introduces a simple and objective formula—the “rule of 11%”—for estimating the ideal breast meridian using measurable preoperative indices. Methods: Data of chest wall width and underbust circumference of 50 patients were collected and analyzed. The ideal nipple position was calculated as 6:4 from the chest wall width and compared with the underbust circumference. Statistical analyses were conducted to evaluate the correlation between the 2 indices and validate the formula. Results: The mean chest wall width and underbust circumference were 30.21 cm and 82.05 cm, respectively. The ideal nipple position, calculated as 6:4 from the chest wall width, closely corresponded to 11% of the underbust circumference, with a mean ratio of 0.111 (11.06%). A strong positive correlation was observed between chest wall width and underbust circumference. Clinical application of the formula in four patients demonstrated accurate postoperative nipple positioning and high patient satisfaction. Conclusions: The rule of 11% provides a reproducible and objective guideline for designing the breast meridian. This bottom-up approach minimizes subjectivity, improves symmetry, and ensures stable and predictable outcomes. This formula is particularly beneficial for novice surgeons and enhances patient satisfaction by aligning with aesthetically ideal nipple positions.
Kim et al. (Wed,) studied this question.