The thoracolumbar spine is the principal load-bearing structure of the
body. As such, it is subject to a wide variety of forces that can be
described by biomechanical principles. Forces act through vectors, dep
ending on the direction of force and the relative location of the inst
antaneous axis of rotation. Patterns of failure due to supraphysiologi
c loading or through the loss of structural integrity may be predicted
based on the applied force vectors and the stabilization components l
ost. An understanding of these forces and their effects on the spine i
s crucial for the safe and efficacious treatment of spinal deformities
.