Diagram of the Genant semi-quantitative grading system for vertebral compression fractures. (a) Anterior wedging: measure the anterior height loss relative to posterior height (i.e., ratio = (P−A)/P × 100%). (b) Biconcave fracture: measure the minimum central vertebral body height relative to posterior height (i.e., ratio = (P−M)/P × 100%). Note that this fracture description is a misnomer because in many cases only one endplate is involved; the term is retained for fidelity with the original Genant grading system. (c) Posterior crush: because the posterior body wall is altered in this type of fracture and cannot serve as its own reference, this height should be measured relative to the posterior height of the adjacent vertebrae. The lower of the two ratios (Phi–P)/Phi and (Plo–P)/Plo is recorded as a percentage. Because L4 is the lowest level scored in Genant, at L4 only the L3 posterior height is used for comparison. Genant grades are: 0, height loss 20% or less; 1 (mild), >20–25%; 2 (moderate), >25–40%; 3 (severe), >40%. (Conceptually similar to figures in Genant 1993, [23], and Siminoski 2014, [24])