Corpus: Vocal muscle

The vocalis muscle is a muscle of the internal laryngeal musculature. It forms the medial part (pars interna) of the thyroarytaenoid muscle.

Originating from the posterior surface of the cartilago thyroidea, the vocalis muscle attaches to the tip of the vocal process of the cartilago arytaenoidea (stellate cartilage). The vocalis muscle has a fibre-like interweaving of muscle fibres from the aryvocalis and thyroovalis muscles.

Innervation is provided by the inferior laryngeal nerve from the recurrent laryngeal nerve. Recent investigations have shown that the thyroarytaenoid muscle may also be supplied by the superior laryngeal nerve and that a connection between the two laryngeal nerves is possible.

As part of the sphincter system of the larynx, its contraction serves primarily to close the upper airways during swallowing and secondarily for voice production.

The vocalis muscle is responsible for maintaining the tension of the vocal folds. The pigtail-like interweaving allows finely differentiated tone gradations. This has a decisive influence on the vocal cords' ability to vibrate.

It mobilises the vibrating mass during increases and decreases in volume through isometric contraction and is the direct antagonist of the cricothyroid muscle, which stretches the vocal folds. It demonstrates its dominance in the lower chest register. The higher the volume and/or the lower the tone, the more dominant it is in the ct/vocalis antagonism. The length is regulated by isotonic contraction.

In addition, the muscle helps to close the intermembranous portion airtight when the glottis is completely closed and increases medial compression (closing force of the vocal folds).