Table 3

Reference intervals for spinal mobility measures

Spinal mobility measureAgePercentiles
2.5th5th10th25th50th75th90th97.5th
ASAS lateral spinal flexion (cm)2516.217.218.220.122.124.126.028.0
3514.715.616.718.520.622.624.426.5
4513.214.115.217.019.121.122.925.0
5511.612.613.715.517.519.621.423.4
6510.111.112.114.016.018.019.921.9
INSPIRE lateral spinal flexion (cm)2529.230.632.235.038.041.143.846.8
3526.427.929.632.535.738.941.845.0
4523.625.127.030.033.436.739.843.2
5520.822.424.327.531.034.637.841.3
6518.019.721.725.028.732.435.839.5
Chest expansion adjusted for height (cm)*253.64.24.96.17.48.79.911.3
353.33.94.65.87.18.59.611.0
453.03.64.35.56.98.29.410.7
552.73.34.15.26.67.99.110.4
652.43.13.85.06.37.68.810.1
Cervical rotation, sitting (degrees)256265697481879399
355962657177848996
455558626774808692
555255586470778289
654851556067737985
Cervical rotation, lying (degrees)256971737781858891
356668717579848791
456164677277818589
555659626773788286
654851556066727782
Intermalleolar distance adjusted for height (cm)*259699104111119126134141
359497102109117125132140
45909498105113121128136
55858993100108116123131
6577818592100108115123
Internal hip rotation adjusted for height (cm)*253235384450576268
353134374349556167
452932364147545966
552831344046525864
652629333844515663
10 cm Schober test (cm)253.43.74.04.65.25.96.67.4
353.33.63.94.45.15.86.47.2
453.23.53.84.35.05.66.37.1
553.13.33.64.24.85.56.27.0
652.93.23.54.14.75.46.16.9
15 cm Schober test (cm)254.54.85.25.96.77.48.18.9
354.24.65.05.76.57.27.98.7
454.04.44.85.56.37.07.78.5
553.84.24.65.36.16.87.58.3
653.64.04.45.15.96.67.38.1
BASMI-original (0–10)250.340.410.500.670.881.141.441.87
350.410.490.590.781.021.311.632.11
450.550.640.760.971.251.591.972.54
550.760.871.021.281.622.042.503.20
651.061.211.391.722.162.683.274.15
BASMI-modified (0–10)250.660.750.861.051.301.581.872.27
350.650.760.891.121.421.762.122.60
450.740.861.011.291.642.042.463.03
550.941.091.261.581.982.442.923.58
651.301.461.662.022.472.993.544.28
  • *Adjusted for height means that the equation for the derivation of the percentiles included height. For these percentiles, the mean height (175 cm) was used. Percentiles for other height values are presented in online supplementary table S6.

  • ASAS, Assessment of Spondyloarthritis international Society; BASMI, Bath Ankylosing Spondylitis Metrology Index.