sternocleidomastoideus

noun
ster·​no·​clei·​do·​mas·​toi·​de·​us | \ -ˌmas-ˈtȯid-ē-əs How to pronounce sternocleidomastoideus (audio) \
plural sternocleidomastoidei\ -​ē-​ˌī How to pronounce sternocleidomastoidei (audio) \

Medical Definition of sternocleidomastoideus