What is the role of the interarytenoid muscle in speech?

The interarytenoid muscle plays a crucial role in speech by acting as the primary adductor of the vocal folds. Its primary function is to bring the two arytenoid cartilages closer together, which in turn helps to close the glottis—the space between the vocal folds. This closure is essential for producing voice, as it allows for the necessary pressure to build up in the vocal tract, enabling sound production. During phonation, when the interarytenoid contracts, it facilitates the vibration of the vocal folds needed for speech.

Understanding its role in adduction clarifies why the other functions listed in the choices do not accurately describe the interarytenoid muscle. For instance, it is not an abductor, which would involve opening the vocal folds; nor does it primarily serve as a tensor, which is more related to altering the pitch of voice. Rather, it primarily focuses on bringing the folds together to facilitate voice production.