title: Estimating the gravity induced three dimensional deformation of the breast.
abstract: As human breast tissue is continuously deformed by gravity, it is difficult to identify the non-loaded neutral breast position from which to take measurements. To estimate the neutral nipple position, this study proposed a simple novel method to counteract the three dimensional effect of gravity on the breast using the buoyant forces from water and soybean oil (ρWATER= 994kgm-3; ρOIL= 909kgm-3). Fourteen female participants with breast sizes ranging from 30 to 34in. under band and B to E cup size took part in this study. Each participant had their static gravity-loaded nipple position measured and their neutral nipple position estimated (as the midpoint between the nipple position during water and soybean oil immersion). Participants were asked to sit in each fluid and fully submerge their torso and breasts. The mean gravity-induced nipple displacements from the neutral nipple position were 15.3mm in the posterior direction, 7.4mm in the lateral direction, and 25.7mm in the inferior direction. Gravity had a significant (p < 0.05, r > 0.82) measurable effect on the static nipple position, particularly in the inferior and posterior directions. Furthermore the density difference between water and soybean oil produced a significant difference (p < 0.05, r = 0.72) in superior-inferior nipple position (5.6mm). These findings suggest that neglect of gravity-induced breast deformations may lead to errors when assessing breast position and its relationship to possible breast pain, and that water alone may not be sufficient to estimate the neutral nipple position.
authors: Department of Sport and Exercise Sciences, Spinnaker Building, University of Portsmouth, PO1 2ER, United Kingdom. Electronic address: chris.mills@port.ac.uk.
authors: Chris
authors: C
authors: Mills
authors: Department of Sport and Exercise Sciences, Spinnaker Building, University of Portsmouth, PO1 2ER, United Kingdom.
authors: Amy
authors: A
authors: Sanchez
authors: Department of Sport and Exercise Sciences, Spinnaker Building, University of Portsmouth, PO1 2ER, United Kingdom.
authors: Joanna
authors: J
authors: Scurr
mesh_terms: D000328:Adult; D001940:Breast / Q000033:anatomy & histology / Q000502:physiology*; D005260:Female; D006112:Gravitation; D006801:Humans; D009558:Nipples / Q000033:anatomy & histology / Q000502:physiology; D055815:Young Adult
keywords: Breast density; Gravitational deformation; Neutral position