According to the concept of sagittal spinal balance, the alternating curves of cervical and lumbar lordosis and thoracic and sacral kyphosis enable the head to be positioned over the trunk and pelvis.

根据矢状面上脊柱平衡的理念，颈椎和腰椎的前凸，胸椎和骶椎的后凸构成的交替曲线使头能够定位与躯体和骨盆的上方。

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According to the concept of sagittal spinal balance, the alternating curves of cervical and lumbar lordosis and thoracic and sacral kyphosis enable the head to be positioned over the trunk and pelvis.

根据矢状面上脊柱平衡的理念，颈椎和腰椎的前凸，胸椎和骶椎的后凸构成的交替曲线使头能够定位与躯体和骨盆的上方。

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