Normal Voice Production
Voice is produced in the voice box or larynx. The human larynx is a cartilage support structure housing the muscles and tissues that produce sound. This is the “Adam’s apple.” During sound production, the lungs fill with air, the vocal cords (or vocal folds) close tightly together, and begin to vibrate as we push air from our lungs through them.
In order for this vibration to take place the vocal folds need to be able to vibrate. The vibration of the vocal folds depends on many factors. Among others, these factors include breath support, the ability to close or oppose the vocal folds, and vocal fold pliability. Normal vocal fold pliability itself depends on many things including overall vocal health, the quality of the mucous lubricating the vocal folds during vibration, and the health of the layers of the vocal folds themselves. Normal vocal folds have layers that must vibrate independently of each other. One of these layers, the superficial lamina propria, is especially important to normal voicing and is frequently involved in vocal problems.
The larynx performs several functions. One, of course, is producing sound. The larynx also functions with the other muscles of the throat to assist in swallowing, coughing, and closing so that we may stabilize the chest in order to lift and strain. All of these functions of the larynx are important for human health.
During vocal full vibration (voicing) the vocal folds vibrate 100s of times per minute and are subjected to considerable stress. The stress that the vocal folds undergo during voicing is known as phonotrauma.
Hoarseness is the common term for a change in the sound of the voice. Many factors contribute to hoarseness including irregularity of vocal fold vibration, dysfunction of the muscles or nerves that control the vocal folds, and other factors including lesions of the vocal folds or nearby structures. There are many types of hoarseness that may give clues as to the underlying cause. For this reason, your doctor may ask whether the hoarseness that you are experiencing is breathy, rough, strained, or halting.
Evaluation of the functions of the larynx (voicing, swallowing, coughing, etc.) may include a physical exam including a full exam of the head and neck, endoscopic exam of the interior of the larynx with a scope or camera, or slow motion video taken of the vocal folds during vibration called stroboscopy. In addition, recordings or other measures of the voice may be taken as well. A full voice evaluation can be performed in the office without preparation by children and adults alike.