Figure 1
The method of thoracic ratios. Chest radiograph to show the method of measurement of calculation of thoracic ratios (TRs). H represents the distance from the upper end-plate of the T1 vertebral body and the lower end plate of T12 vertebral body. D R (D L) represents the distance from the midpoint of the distal end-plate of each vertebra body (T1–12) to the outline of the lateral border of the right (left) thoracic cage. These distances are standardised by dividing by the measured T1 – T12 distance (H). They are termed segmental right and left thoracic ratios TRs. Ratios are also calculated segmentally for the total width of the chest (right plus left measured lengths), [12].