There are two theories for the dynamics of milk expression by the infant. One hypothesis is that milk expression is due to the negative pressure applied by the infant sucking; the alternative hypothesis is that the tongue movement and squeezing of nipple/areola due to mouthing is responsible for the extraction of milk from the nipple. In this study, 3-D two-way Fluid-Structure Interaction (FSI) simulations are conducted to investigate the factors that play the primary role in expressing milk from the nipple. The models include the solid deformation and periodic motion of the tongue and jaw movement. To obtain the boundary conditions, ultrasound images of the oral cavity and motion of the tongue movement during breastfeeding are extracted in parallel to the intra-oral vacuum pressure. The numerical results are cross-validated with clinical data. The results show that, while vacuum pressure plays an important role in the amount of milk removal, the tongue/jaw movement is essential for facilitating this procedure by decreasing the shear stress within the main duct in the nipple. The developed model can contribute to a better understanding of breastfeeding complications due to infant or breast abnormalities and for the design of medical devices such as breast pumps and artificial teats.

中文翻译：

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哺乳期乳房的流固耦合模型。

有两种关于婴儿乳汁表达动力学的理论。一种假设是牛奶表达是由于婴儿吮吸所施加的负压引起的。另一种假设是，由于嘴巴引起的舌头运动和乳头/乳晕的挤压是乳汁从乳头中提取的原因。在这项研究中，进行了3​​-D双向流体-结构相互作用（FSI）模拟，以研究在从乳头表达乳汁中起主要作用的因素。这些模型包括舌头和颌骨运动的固体变形和周期性运动。为了获得边界条件，平行于口腔内真空压力提取口腔的超声图像和母乳喂养期间舌头运动的运动。数值结果与临床数据交叉验证。结果表明，尽管真空压力在脱奶量中起着重要的作用，但通过减小乳头主导管内的剪切应力，舌头/颌骨的运动对于促进该过程至关重要。所开发的模型可以有助于更好地理解由于婴儿或乳房异常引起的母乳喂养并发症，以及有助于设计医疗设备，例如吸奶器和人工乳头。