Biomechanics of milk extraction during breast-feeding

There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

Abstract

How do infants extract milk during breast-feeding? We have resolved a century-long scientific controversy, whether it is sucking of the milk by subatmospheric pressure or mouthing of the nipple-areola complex to induce a peristaltic-like extraction mechanism. Breast-feeding is a dynamic process, which requires coupling between periodic motions of the infant's jaws, undulation of the tongue, and the breast milk ejection reflex. The physical mechanisms executed by the infant have been intriguing topics. We used an objective and dynamic analysis of ultrasound (US) movie clips acquired during breast-feeding to explore the tongue dynamic characteristics. Then, we developed a new 3D biophysical model of the breast and lactiferous tubes that enables the mimicking of dynamic characteristics observed in US imaging during breast-feeding, and thereby, exploration of the biomechanical aspects of breast-feeding. We have shown, for the first time to our knowledge, that latch-on to draw the nipple-areola complex into the infant mouth, as well as milk extraction during breast-feeding, require development of time-varying subatmospheric pressures within the infant's oral cavity. Analysis of the US movies clearly demonstrated that tongue motility during breast-feeding was fairly periodic. The anterior tongue, which is wedged between the nipple-areola complex and the lower lips, moves as a rigid body with the cycling motion of the mandible, while the posterior section of the tongue undulates in a pattern similar to a propagating peristaltic wave, which is essential for swallowing.

Related collections

Most cited references 30

Record: found
Abstract: found
Article: not found

Anatomy of the lactating human breast redefined with ultrasound imaging.

D. Ramsay, J Kent, R. Hartmann … (2005)

The aim of this study was to use ultrasound imaging to re-investigate the anatomy of the lactating breast. The breasts of 21 fully lactating women (1-6 months post partum) were scanned using an ACUSON XP10 (5-10 MHz linear array probe). The number of main ducts was measured, ductal morphology was determined, and the distribution of glandular and adipose tissue was recorded. Milk ducts appeared as hypoechoic tubular structures with echogenic walls that often contained echoes. Ducts were easily compressed and did not display typical sinuses. All ducts branched within the areolar radius, the first branch occurring 8.0 +/- 5.5 mm from the nipple. Duct diameter was 1.9 +/- 0.6 mm, 2.0 +/- 90.7 mm and the number of main ducts was 9.6 +/- 2.9, 9.2 +/- 2.9, for left and right breast, respectively. Milk ducts are superficial, easily compressible and echoes within the duct represent fat globules in breastmilk. The low number and size of the ducts, the rapid branching under the areola and the absence of sinuses suggest that ducts transport breastmilk, rather than store it. The distribution of adipose and glandular tissue showed wide variation between women but not between breasts within women. The proportion of glandular and fat tissue and the number and size of ducts were not related to milk production. This study highlights inconsistencies in anatomical literature that impact on breast physiology, breastfeeding management and ultrasound assessment.

0 comments Cited 57 times – based on 0 reviews      Review now

Bookmark

Record: found
Abstract: found
Article: not found

Anatomy of the human mammary gland: Current status of knowledge.

Foteini Hassiotou, Donna T Geddes (2012)

Mammary glands are unique to mammals, with the specific function of synthesizing, secreting, and delivering milk to the newborn. Given this function, it is only during a pregnancy/lactation cycle that the gland reaches a mature developmental state via hormonal influences at the cellular level that effect drastic modifications in the micro- and macro-anatomy of the gland, resulting in remodeling of the gland into a milk-secretory organ. Pubertal and post-pubertal development of the breast in females aids in preparing it to assume a functional state during pregnancy and lactation. Remarkably, this organ has the capacity to regress to a resting state upon cessation of lactation, and then undergo the same cycle of expansion and regression again in subsequent pregnancies during reproductive life. This plasticity suggests tight hormonal regulation, which is paramount for the normal function of the gland. This review presents the current status of knowledge of the normal macro- and micro-anatomy of the human mammary gland and the distinct changes it undergoes during the key developmental stages that characterize it, from embryonic life through to post-menopausal age. In addition, it discusses recent advances in our understanding of the normal function of the breast during lactation, with special reference to breastmilk, its composition, and how it can be utilized as a tool to advance knowledge on normal and aberrant breast development and function. Finally, anatomical and molecular traits associated with aberrant expansion of the breast are discussed to set the basis for future comparisons that may illuminate the origin of breast cancer. Copyright © 2012 Wiley-Liss, Inc.