The primary function of the larynx is to protect the airways and stop food entering into the lungs. The larynx itself is protected in the neck by an increase in muscle, cartilage and bone. The provision of sound is a secondary function of the vocal folds.

The vocal and vestibular folds close during the acts of swallowing, coughing, excreting, giving birth and when pushing or lifting heavy objects etc. This closing is called constriction.

As we can see here, the vocal folds are suspended over the open space of the trachea, where they act as a sort of portal, through which all the air that comes into and goes out from the body must pass.

We can also see the vestibular or false vocal folds which sit just above the delicate vocal folds, protecting them from damage through strain and swallowing. This is where constriction of the voice and the optimum retraction of false folds occurs.