Cervical muscle volume in individuals with idiopathic neck pain compared to asymptomatic controls: A cross-sectional magnetic resonance imaging study.

•Cervical muscle volumes C3-T1 from MRI were measured.•Muscle volume differed between spinal levels, muscles and muscle groups.•Those with idiopathic neck pain had larger sternocleidomastoid compared to controls.•Older age and female sex were related to less volume, extensor strength with more.•Body mass index was not associated with volume.