MRI study of the cross sectional area for the neck extensor musculature in patients with persistent whiplash associated disorders
From: Manual Therapy. 2008 Jun;13(3):258-65. Epub 2007 Mar 26
Neck muscle function is disturbed in patients with persistent neck pain related to a whiplash associated disorder but little is known about neck extensor muscle morphometry in this group. This study used magnetic resonance imaging to measure relative cross-sectional area of the rectus capitis posterior minor and major, multifidus, semispinalis cervicis and capitis, splenius capitis and upper trapezius muscles bilaterally at each neck segment. In total, 113 female subjects (79 whiplash associated disorder, 34 healthy control; 18-45 years, 3 months-3 years post-injury) were recruited for the study. Significant main effects for differences in muscle and segmental level were found between the two groups as well as a significant group muscle level interaction. The neck multifidus muscle in the whiplash associated disorder group had significantly larger cross sectional area at all spinal levels and in contrast, there were variable differences in cross sectional area measures across levels in the intermediate and superficial extensor neck muscles when compared to the healthy controls. There were occasional weak, although statistically significant relationships between age, body mass index, duration of symptoms and the size of some muscles in both healthy control and whiplash associated disorder subjects. It is possible that the consistent pattern of larger cross sectional area in multifidus at all levels and the variable pattern of cross sectional area values in the intermediate and superficial neck muscles in patients with whiplash associated disorder may reflect morphometric change due to fatty infiltrate in the whiplash associated disorder muscles. Future clinical studies are required to investigate the relationships between neck muscular morphometry, symptoms and function in patients with persistent whiplash associated disorder.
