Adolescent Idiopathic Scoliosis (AIS) is lifetime disorder indicated by the abnormal spinal curvature, and it is usually detected in children and adolescents. Traditional radiographic assessment of scoliosis is time-consuming and unreliable due to high variability in images and manual interpretation. Vertebrae localization and centerline extraction from a biplanar X-ray is essential for pathological diagnosis, treatment planning, and decision making. The aim of this paper is to develop a fully automated framework to provide correct evaluation of anatomical landmarks and to extract vertebral and intervertebral discs’ centroids. By knowing coordinates of each centroid, developed framework will estimate 2D deformity curve (centerline) called Middle Spinal Alignment (MSA) in frontal plane. By analyzing the MSA lines and deformity segments, many deformity parameters can be calculated which include vertebral transpositions, Cobb angles, apex vertebra position, etc., for planning spinal correction strategies and monitoring.