trachealis

noun

tra·​che·​a·​lis ˌtrā-kē-ˈā-ləs  -ˈal-əs 

plural tracheales -ˈā-(ˌ)lēz  -ˈal-(ˌ)ēz 

: a muscle associated with the trachea that in humans consists of smooth muscle fibers extending transversely between the ends of the tracheal rings and the intervals between them at the back of the trachea