Final answer:
The sternohyoid muscle does not elevate the larynx; it is an infrahyoid muscle responsible for depressing the hyoid bone.
Step-by-step explanation:
The muscle that does not elevate the larynx is the sternohyoid. The mylohyoid, geniohyoid, and thyrohyoid are all muscles that participate in the elevation of the larynx or the hyoid bone.
The mylohyoid and geniohyoid muscles are part of the suprahyoid group, which helps raise the floor of the mouth and the larynx during deglutition (swallowing). The thyrohyoid elevates the larynx's thyroid cartilage. In contrast, the sternohyoid muscle is an infrahyoid muscle that depresses the hyoid bone and thus does not elevate the larynx but helps control its position.