- The vocal cords, also known as vocal folds, are paired structures located within the larynx that play a central role in voice production (phonation), airway protection, and regulation of airflow.
- They are composed of multiple layers of tissue and are capable of precise movements and vibrations that generate sound.
- Positioned horizontally within the larynx, the vocal cords stretch from the thyroid cartilage at the front to the arytenoid cartilages at the back, forming the boundary of the glottis, the space between them that opens and closes during breathing and speech.
- Each vocal cord has a complex, layered structure that supports its unique biomechanical properties. From superficial to deep, these layers include: a surface lining of stratified squamous epithelium, a gelatinous superficial lamina propria (Reinke’s space), an elastic intermediate lamina propria, a collagen-rich deep lamina propria, and finally the vocalis muscle (the medial portion of the thyroarytenoid muscle). This layered composition allows the vocal cords to be both pliable and supportive—critical for their vibration and endurance under high mechanical stress during phonation. The vibratory function mainly occurs in the superficial layers, while the deeper layers provide structural integrity and control.
- The process of voice production begins when air is exhaled from the lungs and passes through the glottis. If the vocal cords are brought together (adducted) and sufficient subglottic pressure builds, the cords are forced apart and then snap back together due to elastic recoil and aerodynamic forces, creating a rapid cycle of vibration. These vibrations modulate the airflow and produce sound waves, which are then shaped into speech by the articulators (tongue, lips, palate, etc.). The pitch of the voice is controlled by the tension and length of the vocal cords, primarily regulated by the cricothyroid and thyroarytenoid muscles. Increased tension raises the pitch, while decreased tension lowers it.
- Beyond phonation, the vocal cords serve an essential protective function. During swallowing, they tightly close to prevent the entry of food and liquids into the trachea and lungs, working in concert with the epiglottis and other laryngeal structures. The ability to close the glottis is also critical for reflexive actions like coughing, which clears irritants from the airway, and for generating intra-abdominal and intrathoracic pressure, as during lifting, childbirth, or defecation (via the Valsalva maneuver).
- The health and function of the vocal cords can be compromised by a variety of conditions. Overuse, trauma, infection, inflammation, or exposure to irritants such as smoke and acid reflux can lead to vocal cord pathologies including nodules, polyps, cysts, hemorrhages, or vocal fold paralysis. These conditions often present with symptoms like hoarseness, breathiness, vocal fatigue, or loss of voice. Because of their delicate structure and the high demands placed on them, vocal cords are especially susceptible to damage in professional voice users such as singers, teachers, and broadcasters.
- In medical and research settings, vocal cord function is evaluated through laryngoscopy, stroboscopy, and acoustic analysis. Treatment for vocal cord disorders may involve voice therapy, medical management, surgical intervention, or a combination of approaches. Advances in regenerative medicine and tissue engineering are also exploring the development of bioengineered vocal fold tissue to restore function in patients with severe damage or scarring.
