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Last updated on April 18, 2014 at 12:32 EDT

Larynx

The larynx is an organ that is located within the throat, commonly referred to as the “voicebox”. While the larynx is the primary organ responsible for voice production, it is also crucial in breathing and protecting the airway structures.

Location and Structure

The larynx is a tube-shaped organ with an average length of four inches. It is located between the hypopharynx and the trachea. It is divided into three sections labeled supraglottis, glottis, and subglottis. The skeletal structure of the organ consists of nine cartilages connected to the hyoid bone which is not part of the larynx. Of the cartilage, three are single and three are paired.

Types of Cartilages

Thyroid- connects with the hyoid bone and known as the Adam’s apple.

Cricoid- attached to top of trachea and forms inferior wall.

Epiglottis- forms lid over glottis to protect airway from foreign matter.

Arytenoid- a pair of triangular cartilage located next to thyroid cartilage.

Corniculate- a pair of horn shaped cartilage located below the arytenoid.

Cuneiform- a pair of club shaped cartilage located below the corniculate.

Another part of the structure is the vocal folds, sometimes called vocal cords. These are located where the pharynx meets the tracheal and esophageal openings. There are two sets of vocal folds but only one is the source of the vibration which is the core of sound production. The outer false folds are called the vestibular and provide resonance as their function. The true vocal folds are made up of skeletal muscle in order to perform their function. While these structure stay in close proximity of each other, they as a group do descend in the upper airway around the age of six to eight. This action lengthens the vocal folds and creates a larger vibration range which expands the possible vocabulary. Males’ vocal folds also tend to thicken as they mature which deepens the tone of the vibration.

Function

The larynx produces sound by finely manipulating the structures within itself and with the aide of actions by the tongue, lips, mouth and lungs. As sound travels through the larynx and over the vocal folds, the muscles connected to the folds contract and relax to create different sounds. The sound is actually a vibration that is unique to the vocal fold position based on length and tension. The folds are manipulated with rocking movements of the cartilage rings. The tone and pitch are determined by the pressure created by the mouth and lungs.

Image Caption: Larynx – antero-lateral view, with external muscles of larynx visible. Version with English descriptions on the picture. Credit: Olek Remesz/Wikipedia (CC BY-SA 2.5)

Larynx