Function of speech organ pitch mechanism.

Singing is generally known to be associated with lengthening of vocal ligaments and increasing frequency. At the same time, the anterior vibrating part of both the vocal ligaments become shortened. No explanation based on anatomical grounds has so far been given accounting for this phenomenon and its mechanism. The present paper advocates the crucial role of the elastic fibres (conus elasticus) connecting the upper edge of the cricoid cartilage with the vocal ligament on the circumference in the function of the speech organ pitch mechanism. The vocal ligament is a thickened free cranial margin of this part of the fibroelastic membrane. As the anterior arcus of the cricoid cartilage is approaching the midline of the thyroid cartilage during pitch production the elastic fibres are slackened in their front parts and stretched in their posterior parts, while the vocal ligaments are being stretched. This results in fixation of the posterior node point of the anterior vibrating vocal cord portion and inhibition of their posterior part.