The vocal folds (also: vocal folds, Latin plica vocalis ) are paired structures in the larynx that can vibrate . They are an essential part of the voice-forming apparatus ( glottis ) of the larynx, consisting of the vocal folds covered by epithelium , the actual vocal cord ( ligamentum vocale ), the vocalis muscle and the arytenoid cartilage on both sides. The vocal folds are vibrated on both sides during phonation by blowing from the chest ( Bernoulli effect ) and thus form the primary sound of the voice .
Layout and function
The gap between the vocal cords is called the glottis ( rima glottidis hereinafter). The posterior ends of the vocal folds are connected to the two control cartilages (lat. Cartilago arytaenoidea , Mz. Cartilagines arytaenoideae ), which regulate the position of the vocal folds in relation to one another. When breathing, the vocal folds are wide open, giving the glottis a characteristic triangular shape. The width of the glottis and the degree of its constriction are important for the articulation of speech sounds . The vocal cord muscle can change the tension and thickness of the vocal folds. In connection with the cricothyroid muscle , which also changes the tension and length of the vocal folds, a sensitive control circuit is created which is used to regulate the volume and pitch of the human voice. A number of other muscles are involved in this control loop in different ways.
On both sides of the vocal folds there are pocket folds (plicae vestibulares), which are also called "false vocal cords". Under certain pathological conditions, the pocket folds are primarily or exclusively used for voice formation, which results in a rough and pressed sounding voice (pocket folds voice).
When an opera singer strikes a particularly high note, the vocal folds open and close more than 1,000 times a second. If the voice is interrupted by a glottic obstruction (including short-term larynx obstruction), there is a crackling sound , for example before “u” in “judge” and before all vowels in the initial sound , as in “but”.
The vocal cords can be examined with a larynx mirror or a laryngoscope . During a larynxoscopy, the vibrations of the vocal cords can be assessed using a stroboscope . The vocal cord vibrations can be recorded with a laryngograph for a functional examination .
The vocal folds have a layered structure. The vocal muscle ( Musculus vocalis ) forms the basis , above which lies the lamina propria , which is rich in elastic fibers . From the thyroid cartilage to the arytenoid cartilage, it forms a band-like structure on the vocalis muscle , the vocal ligament , the actual "vocal cord". The surface of the vocal folds and the inside of the arytenoid cartilage are covered by a mucous membrane (mucosa) with a layered squamous epithelium , in contrast to the rest of the larynx, which is lined by a ciliated epithelium. On the vocal fold surface there is a narrow space between the epithelium and the connective tissue, called the Reinke space, named after Friedrich Berthold Reinke , which enables the epithelium to shift in relation to the connective tissue (marginal edge shift). Recent electron microscopic studies have shown that it is not a completely empty space, but also contains compartments. Some scientists even believe that the Reinke room is just an artifact and that the layer of loose connective tissue is better known as the Reinke layer. A (pathological) accumulation of gelatinous fluid in the Reinke area is called Reinke's edema .
Hirano, 1981, grouped the layers of the vocal folds and thus developed the body cover model (table “Layer structure”) with the functional units cover-transition-body. This three- or five-layer model and the different mechanical properties (e.g. density, elasticity, consistency) assigned to the different layers are one of the bases for understanding the movement processes within the vocal folds.
|Lamina propria||upper layer||Mucous membrane||Cover|
|middle layer||Vocal cord||Transition|
|deep layer||Vocal cord||Transition|
Diseases of the glottis
- anatomical changes
- congenital larynx membrane
- functional changes
- Aphonia , voicelessness
Croup , life-threatening narrowing of the larynx due to swelling
- Laryngopharyngeal edema: swelling of the glottis and esophageal entrance, for example during intubation
- Angioedema of the arytenoid cartilage: isolated swelling in the posterior glottic area
- EILO (exercise-induced laryngeal obstruction): Shortness of breath caused by physical exertion due to swelling in the glottic area
- Laryngitis hypoglottica = pseudocroup : shortness of breath due to swelling below the glottis
- neurological changes
- Recurrent palsy : paralysis of the glottis due to changes in the [recurrent nerve]
- New growths of the glottis
Special features in terms of terminology
Colloquially, the vocal folds are also called vocal cords, although the actual vocal cord is only formed by the epithelium and the upper fiber layers.
Vocal cord transplant
The replacement of the vocal folds through tissue engineering is being explored.
- Richard Luchsinger , Gottfried E. Arnold : Handbook of voice and speech medicine. Volume 1: Richard Luchsinger: The voice and its disturbances. 3rd, completely revised and considerably expanded edition. Springer, Vienna et al. 1970, ISBN 3-211-80983-X .
- Richard Luchsinger, Gottfried E. Arnold: Handbook of voice and speech medicine. Volume 2: Gottfried E. Arnold: The language and its disorders. 3rd, completely revised and considerably expanded edition. Springer, Vienna et al. 1970, ISBN 3-211-80984-8 .
- Minoru Hirano: Clinical examination of voice. Springer, Vienna et al. 1981, ISBN 3-211-81659-3 .
- Dissertation - Are there compartments in the Reinke room? (PDF) Retrieved June 26, 2018 .
- A. Prescher: GMS | 27th Annual Scientific Meeting of the German Society for Phoniatry and Pedaudiology V. | Functional anatomy of the larynx. Accessed July 14, 2018 .
- Changying Ling, Qiyao Li, Matthew E. Brown, Yo Kishoto et al .: Bioengineered vocal fold mucosa for voice restoration . In: Science Translational Medicine . tape 7 , no. 314 , 2015, p. 314 , doi : 10.1126 / scitranslmed.aab4014 (English, sciencemag.org [accessed on June 16, 2019]).