Emory University, Atlanta, GA, USA.
Purpose - The concept of natural breast asymmetry is well known, however, actual documentation is limited. New technology is currently available which provides three dimensional surface images of the breast, and the ability to qualitatively determine differences in breast size, shape and contour.
Methods - Eighty seven women without a history of breast cancer or previous breast surgery were included. Images were obtained using 3dMD technology. Data points queried included age, body mass index (BMI), ethnicity and bra size. Left/right images were superimposed and differences in nipple-notch measurements, distance between 2 surfaces and contour were calculated.
Results - The average age was 49.6 years (range: 19-77) with an average BMI of 25 (range: 18.5 - 36.7). The average nipple to notch on the left was 24.3cm, and 23.8cm on the right. The nipple to notch asymmetry was 3.2%, with the left breast measurement being greater the majority of the time. The mean distance between each breast demonstrated consistent breast asymmetry, with an average measurement of +0.5mm (left breast being larger than the right). Breast asymmetry was not related to age, however, was significantly higher in those patients with larger BMI, cup size and chest wall circumference.
Conclusion - Natural breast asymmetry does exist, demonstrated objectively for the first time using three dimensional surfaces images. The left breast is on average larger than the right with differences in size and shape following a fairly unpredictable pattern.