A magnetic resonance imaging investigation into the function of the deep cervical flexors during the performance of craniocervical flexion.
OBJECTIVE
Evidence suggests that the deep cervical flexors (DCFs) are important for the control of the cervical spine. The craniocervical flexion (CCF) test is a clinical test developed for patients with neck pain disorders based on the action of the DCFs. Because these muscles are deeply situated, it is difficult to reach the DCFs with surface electromyography. Magnetic resonance imaging (MRI) can be used to measure these muscles in cross section. The objective of this study was (1) to determine the reliability of MRI for measuring cross-sectional area (CSA) of the longus colli (Lco) and longus capitis (Lca) and (2) to evaluate the changes in CSA during contraction.


METHODS
Thirty healthy subjects aged 29 +/- 9.3 years were imaged using MRI. The CSA of the Lco and Lca was evaluated at 4 different levels (C0-C1, C2-C3, C4-C5, and C6-C7) at rest and during CCF.


RESULTS
The intraclass correlation coefficients for the CSA of the Lco and Lca showed good to excellent reliability (0.73-0.92), except at the C4-C5 level. There was a significant increase in CSA of both Lco (F = 6.79, P = .015) and Lca (F = 19.20, P <or= .001) due to CCF, and this was at different levels. The highest increases in CSA occurred at the C0-C1 level for the Lca (11.1%) and at the C2-C3 level for the Lco (17.4%).


CONCLUSIONS
This study demonstrated that the action of CCF resulted in a contraction of the Lco and Lca at different levels. The results indicate that MRI is a promising technique to evaluate changes in CSA during contraction.
Department of Rehabilitation Sciences and Physiotherapy, Ghent University, Ghent, Belgium. barbara.cagnie@ugent.be
Barbara
B
Cagnie
Roseline
R
D'Hooge
Eric
E
Achten
Dirk
D
Cambier
Lieven
L
Danneels
D000328:Adult; D002574:Cervical Vertebrae / Q000502:physiology; D015986:Confounding Factors, Epidemiologic; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009068:Movement / Q000502:physiology; D009119:Muscle Contraction / Q000502:physiology*; D009334:Neck Muscles / Q000502:physiology* / Q000503:physiopathology; D019547:Neck Pain / Q000503:physiopathology; D015203:Reproducibility of Results; D012107:Research Design