Larynx
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Larynx Key Points
The larynx is a hollow muscular organ in the neck involved in breathing, sound production, and protecting the trachea against food aspirationAnatomy
- Sits Inferior to the hyoid bone and is suspended from it
- Blends with the trachea inferiorly at C6
- Consists of nine cartilages:
- 3 paired cartilages: cuneiform, arytenoid and corniculate
- 3 single cartilages: thyroid, epiglottic and cricoid
Muscles of the larynx
- Contains intrinsic and extrinsic muscles
- Extrinsic laryngeal muscles support and position the larynx within the trachea by elevating or depressing it. They are all attached to the hyoid in some way and can be subdivided into suprahyoid and infrahyoid groups
- The intrinsic muscles are divided into respiratory and the phonatory muscles. They function by altering the position of the arytenoid cartilages.
Diagram illustrating the Larynx
Anterior view of larynx
Posterior view of larynx
Knowledge of the individual muscles is not required for the FRCEM exam but the following is an overview of the functions of the muscles and is here to aid understandingMuscle Group Action Cricothyroid intrinsic lengthen and tense the vocal folds Posterior cricoarytenoid intrinsic abduct and externally rotate the arytenoid cartilages abducting the vocal folds Lateral cricoarytenoid intrinsic adduct and internally rotate the arytenoid cartilages Transverse arytenoid intrinsic adduct the arytenoid cartilages adducting the vocal folds Oblique arytenoid intrinsic narrow the laryngeal inlet by constricting the distance between the arytenoid cartilages Thyroarytenoid intrinsic narrow the laryngeal inlet, shorten vocal folds and lower voice pitch. The internal thyroarytenoid is the portion of the thyroarytenoid that vibrates to produce sound Sternothyroid extrinsic depress the larynx Omohyoid extrinsic depress the larynx Sternohyoid extrinsic depress the larynx Thyrohyoid extrinsic elevates the larynx Digastric extrinsic elevates the larynx Stylohyoid extrinsic elevates the larynx Mylohyoid extrinsic elevates the larynx Geniohyoid extrinsic elevates the larynx Hyoglossus extrinsic elevates the larynx Genioglossus extrinsic elevates the larynx 
Illustration of arrangement of laryngeal muscles
