Table 3.

Between groups comparison of muscle fat infiltration of ventral neck muscles (longus colli = LCO, longus capitis (LCA) and sternocleidomastoid = SCM)

Muscle	LCO left	LCO right	LCA left	LCA right	SCM left	SCM right
WAD < 40*
Median (%)	-0.005	-0.006	-0.04	0.009	0.059	0.041
Range (%)	0.25	0.32	0.22	0.20	0.32	0.30
Number	20	20	20	20	14	15
Drop-out	(0)	0	(0)	(0)	(6)	(5)
WAD ≥ 40*
Median (%)	0.026	0.054	0.011	0.023	0.110	0.104
Range (%)	0.30	0.36	0.33	0.11	0.18	0.21
Number	9	9	9	9	8	9
Drop-out	(2)	(2)	(2)	(2)	(3)	(2)
Controls*
Median (%)	0.019	0.019	0.007	-0,017	0.062	0.019*
Range (%)	0.32	0.41	0.31	0.34	0.25	0.43
Number	28	28	28	28	25	27
Drop-out	(3)	(3)	(3)	(3)	(6)	(4)
p =	0.39	0.75	0.71	0.35	0.25	0.03

WAD   Whiplash Associated Disorders, NDI Neck Disability Index

^*WAD moderate (NDI < 40), severe WAD (NDI ≥ 40) and age- and sex-matched healthy controls

Control vs. severe WAD p = 0.02, control vs. mild WAD p = 0.12, mild WAD vs. severe WAD p = 0.10 (Mann–Whitney U-test)

SCM left vs. right (Wilcoxon signed rank test) p = 0.01 for healthy controls

Drop-out = unclear imaging, impossible to analyse