infrahyoid muscles infrahyoid muscles the infrahyoid muscles, or strap muscles, are a group of four pairs of muscles in the anterior (frontal) part of the neck. the four infrahyoid muscles are the sternohyoid, sternothyroid, thyrohyoid and omohyoid muscles. infrahyoid musclesmuscles of the neck seen from the front. the infrahyoid muscles are coloured in violet.detailsnerveansa cervicalis (except thyrohyoid muscle)actionsdepress the hyoid boneidentifierslatinmusculi infrahyoideita98a04.2.04.001ta22167fma71298anatomical terms of muscle excluding the sternothyroid, the infrahyoid muscles either originate from or insert on to the hyoid bone. the term infrahyoid refers to the region below the hyoid bone, while the term strap muscles refers to the long and flat muscle shapes which resembles a strap. the stylopharyngeus muscle is considered by many to be one of the strap muscles, but is not an infrahyoid muscle. individual muscles the origin, insertion and innervation of the individual muscles: muscleorigininsertioninnervation sternohyoidposterior surface of manubrium sterni, adjoining parts of clavicle and the posterior sternoclavicular ligamentmedial part of lower border of hyoid boneansa cervicalis sternothyroidposterior surface of manubrium sterni and adjoining part of first costal cartilageoblique line of thyroid cartilageansa cervicalis thyrohyoidoblique line of the thyroid cartilagelower border of the body and the greater cornu of the hyoid bonecervical spinal nerve 1 via the hypoglossal nerve omohyoid (superior belly)intermediate tendonhyoid bonesuperior root of ansa cervicalis (c1) omohyoid (inferior belly)superior border of scapulaintermediate tendonansa cervicalis (c1-c3) nerve supply all of the infrahyoid muscles are innervated by the ansa cervicalis from the cervical plexus (c1-c3) except the thyrohyoid muscle, which is innervated by fibers only from the first cervical spinal nerve travelling with the hypoglossal nerve. function the infrahyoid muscles function to elevate and depress the hyoid bone and larynx during swallowing and speech. this moves the larynx as one unit.