Final answer:
The posterior cricoarytenoid muscles are responsible for abducting the vocal cords, enabling breathing by widening the glottis.
Step-by-step explanation:
The muscles that abduct the vocal cords are primarily the posterior cricoarytenoid muscles.
These muscles act to rotate the arytenoid cartilages outwards, which in turn moves the vocal cords away from the midline of the larynx, effectively widening the glottis and allowing for breathing.
Contrarily, the lateral cricoarytenoid and thyroarytenoid muscles, while not directly relevant to the abductive process, act to adduct or close the vocal cords, important during phonation.
Hence, for the broad action of controlling voice modulation, the numerous neck muscles, both suprahyoid and infrahyoid, play significant parts in positioning the larynx and thus influencing the tension of the vocal cords; however, for the specific task of abduction, the posterior cricoarytenoid muscles are pivotal.