Vocal cord

Synonyms

Ligamentum vocale, Ligamenta vocalia (plural)

Anatomy

Like other ligaments in the body, the vocal cords consist of elastic connective tissue. Every healthy person has two vocal chords. These are part of the vocal folds, which are located in the larynx – as vibrating structures of the vocal apparatus (glottis).

The vocal chords lie on the vocal muscle (Musculus vocalis) and are covered by a mucous membrane. These three units – muscle, ligaments and mucosa – together form the vocal folds. The vocal folds, and thus also the vocal cords, are connected to the back with two cartilages (Cartilagines arytaenoideae) and to the chest with the thyroid cartilage (Cartilago thyroidea) and are thus stretched.

The gap between the vocal folds is called the glottis (Rima glottidis) and is the only passage for air between the lungs and the mouth or nose. When breathing calmly, the glottis is only open between the cartilages. The mucous membranes of both vocal folds touch each other and are tightly closed.

The position of the positioning cartilages – during intensified breathing – creates a wide triangular opening of the glottis (front and back part open). Now the vocal folds lie opposite each other open over the entire length and allow the passage of a larger amount of air. Through the vocalis muscle (Musculus vocalis) and the external laryngeal muscle (Musculus cricothyreoideus) we can change the tension, length and thickness of the vocal folds, allowing the glottis to reach different opening states.

Depending on the setting, this causes different pitches and volumes of our voice (except for whispered speech). After inhalation, the vocal folds are closed until they are pressed apart and set in vibration by the exhaled air. The vocal chords open and close as we press air from the lungs through the glottis (phonation), up to over 1000 times per second. When we cough, the glottis opens almost explosively, creating, among other things, the barking sound.

Diseases of the vocal cord

Between the mucous membrane and the vocal cords there is a space (Reinke space), which enables the displacement between the mucous membrane and the ligamentous apparatus. If there is an accumulation of fluid in the Reinke-room, it is called Reinke-edema (see below swelling of the vocal cords). A foreign body in the larynx triggers a cough so that it can be transported towards the mouth.

If this is not possible on its own, you should go to an emergency room as soon as possible. The foreign body should be removed by a physician under visual observation, so that bleeding or residues of the foreign body can be ruled out and possible complications can be avoided. Nervally, the vocal folds are supplied by the laryngeal recurrens nerve.

Injury to this nerve (recurrens paresis) can lead to paralysis of the posticus (Musculus crycoarytenoides posterior), which is also incorrectly called “vocal cord paralysis”. The posticus is the only muscle in the larynx that opens the glottis. A unilateral injury to the muscle or nerve results in a vocal fold that cannot be controlled properly.

This initially manifests itself as a voice change or hoarseness. The very rare bilateral recurrent paresis can lead to breathing difficulties, as the glottis can no longer be opened sufficiently to ensure the passage of air. In addition, vocal fold paralysis is possible due to injury to the laryngeal superior/inferior nerve.

Here the vocal folds can no longer be properly tensioned. In this case, there are no breathing problems, but primarily hoarseness. In the case of intubation (e.g. ventilation under general anesthesia), the breathing tube is passed through the glottis past the vocal cords.

This can lead to irritation of the vocal fold mucosa with hoarseness up to an intubation granuloma. A mostly viral inflammation of the vocal folds (laryngitis acuta) leads to even redness of both vocal folds, whereas a one-sided redness rather indicates a specific inflammation, such as a carcinoma. Particularly in small children, acute laryngitis can lead to edema in the subglottic area, whereby the vocal folds are only slightly reddened (laryngitis subglottica, croup syndrome).

Toxins such as nicotine and alcohol can cause chronic laryngitis of the vocal fold and larynx. In addition, vocal fold polyps can cause hoarseness due to overuse of the voice. A distinction must be made between vocal fold nodules (cry nodules, singer’s nodules).Any hoarseness that lasts longer than 3-4 weeks should be clarified by an ENT physician to rule out a malignant change such as vocal fold carcinoma.