The larynx, or voice box, connects the throat to the windpipe, playing a role in breathing and sound production. This article explores the specific functions of the false vocal cords, structures within the larynx.
Understanding the False Vocal Cords
The false vocal cords, also known as vestibular folds or ventricular folds, are paired structures within the larynx. These shelf-like formations are positioned superior to the true vocal cords. They appear as pink prominences located supero-lateral to the true vocal cords. They consist of mucous membrane, muscle fibers, and connective tissue, making them thicker and more prominent than the true vocal cords.
A key distinction lies in their role in sound production. Unlike the true vocal cords, which vibrate to produce sound during normal speech, the false vocal cords typically have a minimal role in phonation. The space between the false vocal cords is the rima vestibuli, while the space between the true vocal cords is the rima glottidis. This anatomical separation highlights their distinct functions within the larynx.
Their Primary Role: Airway Protection
The primary function of the false vocal cords is to protect the airway from foreign substances, preventing them from entering the lungs. During swallowing, these folds work in coordination with other laryngeal structures, such as the epiglottis, to seal off the trachea. The epiglottis tilts backward, covering the entrance to the larynx, while the false vocal cords approximate, effectively closing the airway. This coordinated action ensures that food and liquids are directed into the esophagus.
The false vocal cords also contribute significantly to the cough reflex, a protective mechanism for expelling irritants from the airway. When a cough is initiated, air is inhaled, followed by the closure of both the true and false vocal cords. This closure helps to build up subglottic pressure within the lungs. The sudden release of this pressure, by the rapid opening of the vocal folds, forcefully expels air and any debris, clearing the airway. This protective closure by the false vocal cords is part of a multi-level sphincteric action.
Beyond Protection: Other Functions
Beyond their role in airway protection, the false vocal cords participate in other physiological actions, including “effort closure.” This mechanism involves the false vocal cords assisting in stabilizing the torso during strenuous activities. When lifting heavy objects or during actions like defecation, they help create pressure within the chest cavity. This increased intra-abdominal and intrathoracic pressure provides a rigid base for muscles to exert force, which can be useful for physical exertion.
The false vocal cords can also become involved in voice production, a phenomenon known as ventricular phonation or false cord phonation. This typically results in a deep, rough, or gravelly voice quality. While not their usual function, this can occur as a compensatory mechanism if the true vocal cords are impaired or unable to vibrate effectively, or it can be purposefully used in certain specialized vocal techniques, such as some forms of throat singing. Ventricular phonation can also be a symptom of vocal strain or other voice disorders, indicating that the false vocal cords are being used abnormally to produce sound.