A, Diagram of measurement technique for assessing rib hump (RH) deformity. RH is linear distance between left and right posterior rib prominences at apex of rib deformity on lateral radiograph. B, Diagram of measurement technique for apical vertebral body/rib ratio (AVB-R). AVB-R is ratio of linear measurements from lateral borders of apical thoracic vertebrae to chest wall on anteroposterior radiographs.