The goal of this study is to characterize the in vitro dynamic response of the human thoracic spine undergoing flexion in the sagittal plane. Eight human functional spinal units (FSU) were harvested from four donors (7, 15, 48 and 52 years old). FSU consisted of three contiguous vertebrae (T2‐T4 and T7‐T9), representing two different regions along the thoracic spine. All ligaments were preserved intact in the preparation of the tissue, with the exception of the inter‐transverse ligaments. Specimens were exposed to a battery of tests using a customized fixture designed to induce a moment at both ends of the specimens. Fung’s quasi‐linear viscoelastic (QLV) formulation was used to model the relationship between the moment applied to one vertebra and the subsequent relative motion with respect to a contiguous one. In general, the upper thoracic FSU (T2‐T4) exhibited a more compliant behavior than the mid‐thoracic segments (T7‐T9) regardless of age. It was also observed that the instantaneous elastic response of the older specimens was stiffer than the one calculated for the younger ones.

To the knowledge of the authors, no characterization of the dynamic flexural behavior of the thoracic spine has been published to date. Therefore, despite the small sample size, the data included in the study can assist in developing more biofidelic models of the human thoracic spine and to benchmark existing ones.