Sex-related differences in sternocleidomastoid muscle morphology in healthy young adults: A cross-sectional magnetic resonance imaging measurement study.

Background: Changes in sternocleidomastoid (SCM) muscle cross-sectional area (CSA) and volume may contribute to neck-related concussion symptoms and whiplash-associated disorders. Magnetic resonance imaging (MRI) data on healthy SCM morphology can provide information that may lead to targeted treatment protocols.

Objectives: To examine sex-related differences in MRI-based SCM CSA, SCM volume and neck area in healthy young adults, to analyze associations between measurements and participant variables and to assess inter-rater reliability for measurement quantification.