This chapter focuses on the finite element method applied to spine modelling. First, the functional biomechanics of the healthy spine are presented in terms of load transfers among the different spinal structures and further related to the pathologic and treated spine. This overview naturally justifies the finite element method as a particularly convenient tool to explore the spine as an integrated organ where tissue maintenance and degeneration are strongly influenced by complex mechanical factors. The different approximations usually used in spine finite element analysis are presented and discussed in relation to the exploitability of the predictions and the computational cost. On one hand, spine models require thorough verification and improved validation protocols. On the other hand, the rapid mechanistic developments proposed are continuously increasing the reliability of both model calibration and predictions on a clinical basis, suggesting that spine finite element models will probably become highly valuable clinical tools in the near future.