The lower lumbar region is the transition region that geometrically provides the lumbar lordosis and lumbosacral angles with the gravity line passing from the front and the C7 plumb line passing from the back in the sagittal plane. Because of the facet joints oriented in the sagittal plane, translation and rotation are prevented while allowing maximum flexion and extension movements. The instantaneous axis of rotation is generally located within the disc space and close to the upper end plate of the vertebra in all movements. Intradiscal pressure is highest in this region. Surgically, it should be kept in mind that axial rotation increases on the contralateral side after unilateral total facetectomy.