Corpus: Vocal fold

The vocal folds are two horizontal folds of tissue covered with mucous membrane within the larynx that are responsible for voice production (phonation).

The base of the vocal folds is formed by the vocalis muscle (vocal muscle). The vocal ligament (vocal cord), which is rich in elastic fibres, is attached medially. It runs on both sides in a band from the cartilago thyroidea to the cartilago arytaenoidea. The surface of the vocal folds is covered by a mucous membrane consisting of multilayered, uncornified squamous epithelium. Between the epithelium and the musculature there is a narrow, gelatinous space, the Reinke space, subepithelially in the uppermost layer of the lamina propria.

The two vocal folds form a variable, slit- to triangular-shaped opening in their centre, the glottidis rima (glottis). Cranial to the vocal folds are the pocket folds (plicae vestibulares), which are also known as false vocal folds.

Inside the larynx, the vocal folds form the boundary between the cranial ventriculus laryngis and the caudal cavitas infraglottica (lower laryngeal floor).

The vocal folds serve as an inhalation or negative pressure valve. During normal expiration, air escapes passively from the lungs and sets the vocal folds in motion. These are adjusted and stretched by the phonation muscles, which results in voice formation. Together with the vestibular plicae (pressure relief valve), the vocal folds form the laryngeal double valve function.

The vocal folds can be affected by various diseases. These include

• vocal fold polyp
• vocal fold granuloma
• Laryngitis
• Dysphonia, e.g. hyperfunctional dysphonia with increased vocal stress
• Vocal cord dysfunction