Ultrasound and MRI measurements
| Ultrasound measurements between bony landmarks (cm) | |||||||||||||||
| Distance between | Intermammillary distance, right side | Intermammillary distance, left side | Spinous processes | ||||||||||||
| Segment (number of levels) | L4/L5 (1) | L3/L4 (1) | L2/L3 (1) | AVG | L2/L5 (3) | L4/L5 (1) | L3/L4 (1) | L2/L3 (1) | AVG | L2/L5 (3) | L4/L5 (1) | L3/L4 (1) | L2/L3 (1) | AVG | L2/L5 (3) |
| Mean | 2.55 | 2.90 | 3.21 | 2.89 | 8.67 | 2.69 | 2.93 | 3.21 | 2.95 | 8.84 | 2.61 | 2.91 | 2.94 | 2.81 | 8.44 |
| SD | 0.29 | 0.28 | 0.38 | 0.33 | 0.81 | 0.27 | 0.32 | 0.33 | 0.26 | 0.63 | 0.37 | 0.28 | 0.38 | 0.18 | 0.75 |
| MRI-measured IVD height (cm) | |||||||||||||||
| Disc levels | L4/L5A | L4/L5M | L4/L5P | L4/L5AVG | L3/L4A | L3/L4M | L3/L4P | L3/L4AVG | L2/L3A | L2/L3M | L2/L3P | L2/L3AVG | AvLx L2–L5 | L2–L5 | |
| Mean | 0.84 | 0.92 | 0.53 | 0.76 | 0.75 | 0.86 | 0.50 | 0.70 | 0.64 | 0.75 | 0.48 | 0.63 | 0.70 | 8.31 | |
| SD | 0.17 | 0.15 | 0.10 | 0.12 | 0.12 | 0.14 | 0.09 | 0.10 | 0.17 | 0.14 | 0.13 | 0.12 | 0.11 | 0.30 | |
A, anterior; AVG, average; AvLx, average IVD height derived from the L2/L3, L3/L4 and L4/L5 levels; IVD, intervertebral disc; M, middle; P, posterior.