Morphology and composition of the ventral neck muscles in individuals with chronic whiplash related disorders compared to matched healthy controls: a cross-sectional case–control study

Abstract

Background Objective Studies of cross-sectional area (CSA) (morphology) and muscle fat infiltration (MFI) (composition) in ventral neck muscles is scarce in patients with chronic whiplash associated disorders (WAD), especially for men and those with severe WAD compared with matched healthy controls. The aim was to compare CSA and MFI of sternocleidomastoid (SCM), longus capitis (LCA) and longus colli (LCO) in patients with chronic right-sided dominant moderate (Neck Disability Index: NDI < 40) or severe WAD (NDI ≥ 40), compared to age- and sex-matched healthy controls. Methods Cross-sectional case–control study with blinded investigators. Thirty-one patients with chronic WAD (17 women and 14 men, mean age 40 years) (SD 12.6, range 20–62)) and 31 age- and sex-matched healthy controls underwent magnetic resonance imaging of ventral neck muscles segmental level C4. Results Unique to the severe group was a larger magnitude of MFI in right SCM (p = 0.02) compared with healthy controls. There was no significant difference between the groups with regards to the other muscles and measures. Conclusions Individuals with severe right-sided dominant WAD have a higher MFI in the right SCM compared to healthy controls. No other differences were found between the groups. The present study indicates that there are changes in the composition of muscles on the side of greatest pain.

Altered neck muscles function during cervical rotation in chronic whiplash-associated disorders improved after neck-specific exercises: a real-time ultrasound case-control study

“…The voluntary neck muscle's function was not based only on biomechanics 36 , movements were related to the combination of numerous muscles and there were differences between voluntary preferred activation and the measured biomechanical directions. Changes in the muscle's composition on the side of greatest pain was also seen in WAD, with increased fatty in ltration in Sternocleidomastoid in the pain dominant right side but not in the left side 37 .…”

Results of neck-specific exercise for altered postural sway in individuals with chronic whiplash-associated disorders: a longitudinal case–control study

“…They have lower neck muscle endurance 36 , altered intermuscular interplay in the neck with less activation of the deep neck muscles and less synchronization between the deep and superficial muscle layers 15 , and impaired sensorimotor function 24 . Moreover, fatty infiltration in the neck muscles (contractile muscle tissue replaced with fat) has been reported in WAD 8 – 10 , especially in the deep neck muscles which contain many proprioceptors that are important for maintaining the sensorimotor system and balance 11 – 13 . Individuals with WAD who had a disturbed neck proprioception had to rely on visual feedback for balance performance.…”

“…Research studies have shown increased fatty infiltration in WAD 8 – 10 , especially in the deep neck muscles which contain many proprioceptors that are important for maintaining the sensorimotor system and balance 11 – 13 . Furthermore, decreased neck muscle endurance, altered sensorimotor function, altered movement pattern and disturbed eye-neck control have been reported 14 – 24 .…”

Exploring the Impact of Cervical Multifidus Muscle Morphology on Postural Balance in Post-Stroke Patients: A pilot study

“…These findings are intriguing and warrant further discussion in the context of current literature on the subject. Several studies have examined the relationship between cervical multifidus muscle morphology and postural balance in different populations, including individuals with musculoskeletal disorders and neurological conditions [23][24][25]. Some of these studies have reported significant associations between cervical multifidus muscle morphology and postural balance, suggesting that alterations in muscle structure could contribute to postural instability [26].…”