reproducibility of the ultrasonography in measuring the cross-section of the longus colli in patients with non-specific neck pain

Purpose: ultrasonography (us) can be used to measure the dimensions and the cross-section of muscles. this study aims to investigate the intra- and inter-tester reproducibility of the us measures of the cross-section of the longus colli (lc) muscle at rest and in contraction states in patients with chronic non-specific neck pain (cnsnp) and healthy individuals.methods: this cross-sectional study was conducted on seven healthy individuals and seven patients with chronic non-specific pains. the cross-section of the lc muscle was measured at rest and in contraction states at the c5-6 vertebrae by two raters using the us on two consecutive days. the data were analyzed by the pearson correlation coefficient (icc).results: the intra-tester reproducibility was excellent in the healthy (icc>0.97) and patient (icc>0.95) groups at rest and in contraction. the inter-tester reproducibility was great in the healthy group (icc>0.97) in both states and at rest (icc=0.98) and in the contraction (icc>0.95) in the patient group.conclusion: the results revealed that the us demonstrated higher agreement in measuring the cross-section of the lc in healthy subjects and patients with cnsnp. thus, this method is reliable and can be used to measure the cross-section of the muscles.