Laryngeal Anatomy 101

This article will introduce you to the basic anatomy of the larynx. This is a very simplified version that is only intended to get you started, if you want to dive into this subject more deeply, check out Dr. Scott McCoy’s book “Your Voice: An Inside View.”

The Larynx

“Larynx” is a term used to describe the vocal mechanism as a whole. The larynx rests between the tongue and the trachea. The primary structure consists of the cricoid cartilage, thyroid cartilage, and hyoid bone.

Cricoid Cartilage

The cricoid cartilage is shaped like a signet ring and
attaches to the trachea. It serves as the base for the thyroid cartilage, which tilts on top of the cricoid cartilage when changing pitch.

Signet ring

Thyroid Cartilage

The thyroid cartilage is shaped like a Roman scotum shield.

Scotum shield

The cartilage surrounds the vocal folds, which attach behind the laryngeal prominence (aka the “Adam’s Apple”). The thyroid cartilage attaches to the cricoid cartilage via the “inferior horns.” When ascending the scale, the thyroid cartilage tilts forward on this joint. At the top of the thyroid cartilage there are two horns that stick up, called the superior horns. These attach to the hyoid bone.

Hyoid bone

The hyoid bone connects the tongue to the larynx.

Arytenoids

The arytenoids sit atop the cricoid cartilage and allow the vocal folds to open and close. The arytenoids are synovial joints, meaning they can move in multiple directions much like your elbows.

Epiglottis

The epiglottis is an elastic cartilage that covers the vocal folds during swallowing to prevent liquids and solids from entering the lungs.

Thyroarytenoid muscle

The thyroarytenoids are a pair of muscles that form the main body of the vocal folds. The muscle originates at the thyroid cartilage and attaches to the arytenoids. When it contracts, it pulls the arytenoids towards the thyroid cartilage, simultaneously shortening and thickening the vocal folds.

Cricothyroid muscle

The cricothyroid muscles are found on both sides of the larynx. The muscles originate at the cricoid cartilage and connect to the thyroid cartilage. When they contract, they tilt the thyroid cartilage forward, which is hinged to the cricoid cartilage via the inferior horns. The the thyroid cartilage is tilted forward, the arytenoids remain stable and thus the vocal folds are elongated, simultaneously raising pitch and thinning the folds.

Interarytenoid muscle

The interarytenoid muscle connects the two arytenoid cartilages in the posterior part of the larynx. When these muscles contract, they pull the arytenoids together. This action assists in closing the vocal folds for phonation. It is also believed that the action of these muscles assists in thickening the vocal folds.