Vocal cords or vocal folds are structures in the larynx which are designed to vibrate when air passes by, producing sound. These structures allow people to speak, and they also help to protect the lungs from accidental inhalation of food, saliva, and mucus. Animals also have vocal folds, which allows them to vocalize. A number of disorders can involve the vocal cords, and as a general rule, such conditions need to be treated promptly because they can become life threatening.
The true vocal cords are found just above the trachea and below the epiglottis. They consist of two bands of tissue which stretch horizontally across the larynx. Contracting or relaxing the cords allows their owner to permit the free flow of air through the throat, or to restrict it. By making tightly controlled contractions, someone can speak and produce other sounds. The pitch of the sound is determined by a number of factors, including the size and tension of the vocal cords. Men tend to produce lower pitches, while children produce sounds at a higher pitch.
Just above the true vocal cords, two similar structures known as the vestibular or false folds can be found. The false folds do not generally contribute to the production of sound, although people can train themselves to use them, as is done in several traditional singing techniques. Together, the two sets of folds in throat can be contracted to open up the throat, or relaxed to fill it. The vestibular folds are slightly thicker and larger than the true vocal folds.
Because these cords must be highly flexible and strong, they are very elastic, and they are covered in a layer of mucus membranes. When the vocal folds are visible during surgery, endoscopy, and similar procedures, they appear almost white in color, because they have a limited blood supply.
A number of things can cause damage to the vocal cords, including infections, voice strain, polyps, nodules, irritation, and swelling. Some people can even develop paralysis, in which the vocal cords cannot be moved, which can affect the ability to speak or breathe. These conditions can cause permanent damage if they are allowed to persist, and they can potentially be very dangerous, making it important to see a doctor for issues related to these structures. Physical or speech therapy, surgery, and medication are all approaches to vocal cord disorders.