**2.4. Measuring spinopelvic alignment**

Assess a patient's sagittal alignment allows the practitioner to objectively understand its potential role in contributing to a patient's pain and dysfunction. In 2006, the Scoliosis Research Society published the first classification system to develop a common language around adult spinal deformity (ASD). This classification grew out of an understanding that the existing adolescent scoliosis classifications were not entirely applicable to the adult population when making clinical decisions around operative management. The most recent update on this classification emphasizes the importance the sagittal plane plays in maintaining healthy upright spinal postures. Their work is valuable for the conservative care practitioner to help make clinical predictions as to the contribution of alignment to pain in our patients with spinal deformity [20].

The first step of the classification is to identify the coronal curve type, depending on the location of the curve apices and convexities. The categories are thoracic, thoracolumbar/lumbar, or double curve. The second step is to assess for the presence of sagittal modifiers. These modifiers include pelvic incidence (PI), global alignment via sagittal vertical axis (SVA), pelvic tilt (PT), degree of lumbar lordosis (LL), as well as subluxation or listhesis in the frontal or sagittal plane [20].
