Deborah Aloba - Singing Teacher

Deborah Aloba - Singing Teacher

The Secret is in the Structure

The key to the story of vocal nodules lies in our understanding of the layered structure of the vocal folds.

A flexible mucus membrane forms the outer covering of the vocal fold (the epithelium).

Beneath are several layers of connective tissue (the Lamina Propria). The outer (superficial) layer is gelatinous in nature and separates the outer (epithelial) cover from the stiffer underlying vocal ligament. Beneath the ligament lies the vocalis muscle.

Just to confuse things, the literature often refers to the vocal fold “cover” and “body”, where the cover is considered to include the epithelium and the superficial (gelatinous) layer of the lamina propria, while the body includes the ligament and underlying muscle. In this text I refer to the epithelium as the “outer covering” of the vocal fold and it is not to be confused with the idea of “cover” described above).

The epithelium is exposed to a considerable upwards force as the air rushes between the vocal folds during voicing. The gelatinous layer of the Lamina Propria cushions the epithelium by allowing it to slide upwards and outwards in response to the air pressure. This upward and outward movement of the epithelium is visible when the vocal folds are examined under stroboscopic light like waves breaking over the upper surface of the vocal fold. The movement is known as the “Mucosal Wave”.

A clear voice quality depends on whether or not the vocal folds can generate normal mucosal waves. Any condition that “tethers” the epithelial cover to the underlying ligament will disrupt or reduce the mucosal wave. The vocal folds will no longer vibrate efficiently over the affected area and the voice quality may be altered.

Fortunately, soft nodules only affect the superficial (outer) layer of the vocal fold and even hard nodules are only very rarely associated with this type of tethering.