Fig. 1From: Risk factors for lumbar intervertebral disc height narrowing: a population-based longitudinal study in the elderlyDisc height measurement. Ha: anterior disc height, Hp: posterior disc height, Ds: superior disc depth, Di: inferior disc depth. Disc height is expressed as the disc height index (DHI), which was calculated as: [(Ha + Hp)/(Ds + Di)] × 100Back to article page