Fig. 2

Diagram of the measurements of HV parameters. Left, HV was categorized into two groups according to whether the width extend across the “midline”, meaning the central vertical line (CVL) of distal adjacent vertebra (DAV). Middle, lateral height around HV (from HV-1 to HV + 1) was measured on convex side. The lateral height ratio (LHR) was defined as illustrated to assess the longitudinal development of HV. Right, sagittal position was divided into lateral and posterolateral group according to whether the HV extended ventrally to the anterior half of vertebral column