The upper area dilator muscles represent a subgroup of muscles located in the pharyngeal area. In addition to their role in vocalizing, they also have important respiratory functions.
Muscles cannot extend by themselves and need/depend on other muscles to extend, that is referred to as an antagonism.
The obturator muscle is also extended by an antagonism.
The obturator muscle is composed of the lateral cricoarytenoid muscle, the transverse arytenoid muscle, and the thyroarytenoid muscle.
No one can recognize the right position of these muscles, how to move/control them or the statuses of these muscles on their own.
The muscles of vocalizing are really special and unique.
The ‘antagonistic muscle’ of the lateral cricoarytenoid muscle, the transverse arytenoid muscle and the thyroarytenoid muscle is the posterior cricoarytenoid muscle.
The posterior cricoarytenoid muscle is very big to be able to support three other muscles.
Therefore, if the posterior cricoarytenoid muscle can move very well, and makes it possible to close the glottis tightly.
Note1:The oblique arytenoid muscle supports the transverse arytenoid muscle in moving properly.