Measurement of breast volume: comparison of techniques.

A system of graduated disks has been previously described as a method to determine breast volume. The accuracy and limitations of this system have not previously been reported. Comparison of these disks with a standardized volumetric method shows this simple system to be accurate. Standard linear correlation analysis was good for the entire group of breasts measured (r = 0.718). Conversion to true volume M is represented by the least-square line M = 20.33 + 1.37G. The correlation is expected to fail at volumes greater than 425 cc (greater than the calibration on the largest Grossman disk). Elimination of volumes greater than 425 cc, however, produced no improvement in correlation coefficient. Firm breasts (i.e., capsular contractures) displace less uniformly into the conical restraint of the disk and cause an overestimation of their volume. Three breasts in this series were evaluated with Baker grade III and IV capsular contractures. Elimination of these values improved the correlation between the two volume analyses (r = 0.853 and M = 1.56G - 4.48). We suggest that when confronted with very large or firm breasts that volumes determined by the Grossman disk be interpreted with care. A formula for calculation of the true breast volume from the Grossman measurement has been derived and presented.