Ultrasonography of the Cervical Muscles: A Critical Review of the Literature

ObjectiveThis article presents a review of the literature concerning size measurement of cervical muscles using real-time ultrasound imaging (RUSI) in patients with neck pain and in healthy populations.MethodsA literature search from 1996 to December 2009 making use of Science Direct and PubMed databases was conducted. Medical Subject Headings and other terms were as follows: ultrasonography, cervical, muscle, neck, size, pain, validity, reliability, neck pain, and healthy subjects. We included studies using RUSI for assessing cervical paraspinal muscles both in healthy subjects and in patients with neck pain. We assessed muscles investigated and the reliability and validity of the method used.ResultsThe literature search yielded 16 studies. Twelve (75%) studies assessed the posterior muscles, whereas in the remaining 4 (25%), the anterior muscles were studied. Three studies quantified the size of the muscles during contraction; 3 assessed the relationship between cross-sectional area, linear dimensions, and anthropometric variables; 1 evaluated the training-induced changes in muscle size; 1 assessed the differences in muscle shape and cross-sectional area of cervical multifidus between patients with chronic neck pain and controls; 8 studies looked at the reliability of using RUSI in patients with neck pain or healthy subjects; and 3 studies evaluated the validity of RUSI compared with magnetic resonance imaging.ConclusionsThis literature review has shown that there are not sufficient studies for assessing neck muscles with RUSI. It seems that using constant landmarks, knowledge of anatomy and function of target muscle, and a proper definition of muscle borders can help to take a clear image. Standardized position of the subject, correct placement of the transducer, and using multiple RUSI for statistical analyses may improve results.