**1. Introduction**

Spinal Deformity may be defined as an abnormality in alignment, formation, or curvature of one or more portions of the spine [1]. Spine deformities can occur in one or a combination of the axial, coronal, and sagittal planes. Scoliosis is a spinal deformity defined by the Scoliosis Research Society (SRS) as a lateral curve measuring 10° or more on an anterior-posterior radiograph with the presence of vertebral rotation [2].

In recent years, attention to the role of sagittal plane alignment in the overall health and function of adults with spine deformity has increased [3]. The purpose of this chapter is to shed light on the body of literature surrounding sagittal alignment variations and hypothesize about clinical implications for the conservative care practitioner managing spinal deformity in clinical practice.
