Table 1: Cross-sectional area of back muscles and association with LBP.

ResearchModalityParticipantsSegments measuredLevel of measurementPositionOrientation of cross sectionCSA multifidus (cm2)CSA erector spinae (cm2)Association with LBP

Danneels et al. [50] CT23 healthy volunteersL3
L4
L4
Superior endplate
Superior endplate
Inferior end plate
SupineAdjacent to the vertebral endplate4.7 ± 1.4
6.3 ± 1.4
9.0 ± 1.5
A significant difference between the two groups, especially at the L4 inferior endplate. Healthy individuals have a larger CSA of the multifidus
32 patients with LBPL3
L4
L4
Superior endplate
Superior endplate
Inferior end plate
4.1 ± 1.0
5.7 ± 1.1
7.7 ± 1.4

Hides et al. [51] US10 young male elite cricketers with LBPL2
L3
L4
L5
Spinous process of the vertebraProne with flattened lumbar lordosisBetween the spinous process and the lamina3.4 ± 1.4
5.1 ± 1.9
7.1 ± 2.7
7.4 ± 2.1
Multifidus muscle atrophy can exist in highly active, elite athletes with LBP. Specific retraining resulted in an improvement in multifidus CSA that was concomitant with pain decrease
16 young male elite cricketers asymptomaticL2
L3
L4
L5
2.8 ± 1.1
4.3 ± 1.5
6.5 ± 2.2
8.0 ± 1.7

Stokes et al. [19] US68 femalesL4
L5
Prone with flattened lumbar lordosisBetween the spinous process and the lamina5.6 ± 1.3
6.7 ± 1.0
52 malesL4
L5
7.9 ± 1.9
8.9 ± 1.7

Chan et al. [27] US12 asymptomatic menL4Vertebral laminaProne6.16 ± 0.09Smaller multifidus CSA in chronic LBP patients than that in controls at all postures
Standing7.16 ± 0.10
12 men with LBPL4Prone5.37 ± 0.06
Standing6.58 ± 0.20

Fortin et al. [33] MRI33 patients diagnosed with posterolateral disc herniation at L4-L5L3-L4
L4-L5
The center of each intervertebral discSupinePerpendicular to the muscle mass6.5 ± 1.4
9.6 ± 2.1
20.0 ± 4.4
16.3 ± 4.1
There was no significant asymmetry of the multifidus at spinal level above, same level, or level below the disc herniation
L5-S1
S1
The center of S1 vertebral body11.7 ± 2.3
13.2 ± 2.7
10.2 ± 4.1
9.1 ± 4.0

D’Hooge et al. [25]MRI13 individuals with recurrent nonspecific LBP, and 13 asymptomatic individualsL3
L4
L4
Superior endplate
Superior endplate
Inferior end plate
SupineAdjacent to the vertebral endplateNormalized values to L4 superior endplateNo difference in CSA between individuals with LBP and controls

Niemeläinen et al. [35]MRI126 asymptomatic menL3-L4
L4-L5
L5-S1
Not described in the manuscriptSupineNot described in the manuscriptRt: 7.3, Lt: 6.9
Rt: 10.1, Lt: 9.5
Rt: 11.1, Lt: 9.8
Rt: 19.6, Lt: 19.7
Rt: 14.3, Lt: 15.3
Rt: 9.4, Lt: 10.4
Paraspinal muscle asymmetry >10% was commonly found in men without a history of LBP. This suggests caution in using level- and side-specific paraspinal muscle asymmetry to identify subjects with LBP and spinal pathology

Sions et al. [36]MRI13 older adults with chronic LBP, age 60–85 yL2
L3
L4
L5
Through vertebral body3.44 ± 0.94
5.07 ± 2.02
8.76 ± 3.02
9.35 ± 1.83
18.76 ± 4.46
17.63 ± 4.00
13.51 ± 2.00
3.61 ± 1.19

LBP: low back pain, CSA: cross-sectional area, Rt: right side, and Lt: left side.