Ultrasonographic assessment of cross-sectional area of deep neck flexor muscles during a five-stage cranio-cervical flexion test in individuals with chronic neck pain and healthy controls

Aims: The objective of this study was to investigate and compare the cross-sectional area (CSA) of deep neck flexor muscles (DNFs) in individuals with chronic non-specific neck pain (CNNP) and healthy controls while performing a five-stage cranio-cervical flexion (CCF) test. Methods: Twenty individuals with CNNP and 20 healthy controls voluntarily participated in this case-control study. Cross-sectional area of DNFs was measured using ultrasonography while the participants lay in supine position to perform the CCF test. The five stages of the CCF test were determined by a pressure biofeedback tool. Neck disability index and pain were also assessed. Repeated measures analysis of variance was used to interpret the yielded data. Results: A significant difference was observed in the CSA of DNFs between individuals with CNNP and healthy controls at the pressure of 24 mm (p = .009) of the CCF test. The CSA of DNFs significantly changed through increasing the CCF test pressure. No significant differences were observed on the right and left-side DNFs, neither in healthy controls, nor in individuals with CNNP. Conclusions: The CSA changes in individuals with CNNP and healthy controls significantly varied during the CCF test, which may be a reasonable explanation to the muscle weakness and atrophy in individuals sustaining CNNP.