Larynx Anatomy Introduction

The larynx, commonly known as the voice box, connects the laryngopharynx and the trachea. The larynx runs from the third to sixth cervical vertebrae (C3-C6) and lies in front of the laryngopharynx.

The main structure of the Larynx is composed of nine pieces of cartilages which is connected to one another by muscles and ligaments. The larynx can be split into exterior and interior structures.

Exterior Structures

Thyroid Cartilage

Cricoid Cartilage

Arytenoid Cartilage

Epiglottis 

Interior Structures

Vocal Cords

Larynx Position

Superior – Hyoid Bone and the root of the tongue

Inferior – Trachea

Anterior – Hyoid bone and neck muscles

Posterior – Laryngopharynx, Oesophagus and C3-C6.

Larynx Structures

The thyroid cartilage is the largest cartilage of the larynx and lies in the front of the neck. It is typically larger and more prominent in males, giving rise to the “Adam’s apple” or “Adam’s apple prominence,” a noticeable bulge in the neck. The thyroid cartilage forms most of the anterior and lateral walls of the larynx and is made of hyaline cartilage.

The thyroid cartilage is located just below the hyoid bone and above the cricoid cartilage. It forms the anterior wall of the larynx and protects the vocal cords and other structures within the larynx. The cartilage is incomplete posteriorly and is bound by ligaments to the hyoid bone and cricoid cartilage.

The cricoid cartilage is a ring-shaped structure located just below the thyroid cartilage in the larynx. It is the only complete ring of cartilage in the larynx and again is made of hyaline cartilage.

The anterior aspect of the cricoid cartilage is narrow when compared to the posterior aspect. The broad posterior part articulates with the arytenoid cartilage and thyroid cartilage. The lower border of the cricoid cartilage signifies the end of the upper respiratory tract.

The arytenoid cartilages (pyramid shaped) are located on the superior surface of the cricoid cartilage. They sit at the back of the larynx and are attached to the broad part of the cricoid cartilage which forms part of the posterior wall of the larynx. They help with attachment of the vocal cords and muscles and again made from hyaline cartilage.

The epiglottis is composed primarily of fibroelastic cartilage, which allows it to bend and flex. It is a broad, leaf-like shape with a stalk or base that is attached to the anterior wall of the thyroid cartilage.

The epiglottis rises upwards behind the tongue and the body of the hyoid bone where the top of the epiglottis is rounded and is covered with stratified squamous epithelium.

The vocal cords are two folds that are composed of several layers of tissue, including epithelium, ligaments, and muscle fibres. They have a three-layered structure: the mucous membrane (cover), the vocal ligament (middle layer), and the vocalis muscle (body). This complex structure gives the vocal cords their elasticity and ability to vibrate.

They extend from the anterior inner wall of the thyroid to the arytenoid cartilage posteriorly. When the muscles controlling the vocal cords are relaxed, they allow air to pass through also known as abducted. When the muscles contract the vocal cords are stretched and depending upon the tension applied determines the voice pitch.

Overview Of Larynx Structure

Below shows interactive images of the larynx structure. Why not test your knowledge by labelling each part of the larynx before viewing the answer?

To view the interactive structure of the Pharynx head over to this page on a tablet or PC!

Function Of The Larynx

Sound Production: The larynx is crucial for generating sound, which is essential for speech, singing, and vocal communication. The vocal cords (also known as vocal folds), which vibrate as air passes through them. The tension and position of the vocal cords can be adjusted to produce different pitches, tones, and volumes of sound. This ability allows for the production of a wide range of vocal sounds and facilitates spoken language and vocal expression.

Airway Protection: The larynx plays a vital role in protecting the airway during swallowing. It houses the epiglottis, that covers the entrance to the larynx and trachea during swallowing. This protective mechanism prevents food, liquid, and saliva from entering the airway and directs them toward the oesophagus for safe passage into the digestive system.

Respiration Regulation: The larynx helps regulate airflow during breathing. It contains muscles that can adjust the size of the airway, controlling the flow of air into and out of the lungs. By adjusting the position of the vocal cords and other laryngeal structures, the larynx can modulate airflow to meet the body’s respiratory needs, such as during speech, coughing, and exertion.

Larynx Blood Supply

Blood is supplied via the superior and inferior laryngeal arteries with venous return by the thyroid veins which joins the internal jugular vein.

Conclusion

The larynx, also known as the voice box, is a vital organ located in the throat responsible for producing sound, protecting the airway during swallowing, and facilitating breathing.

Key Points

Bibliography

Larynx Anatomy: Gross Anatomy, Functional Anatomy of the Larynx, Laryngeal Tissue. (2021). EMedicine. https://emedicine.medscape.com/article/1949369-overview?form=fpf

Suárez-Quintanilla, J., Alejandro Fernández Cabrera, & Sandeep Sharma. (2020, May 12). Anatomy, Head and Neck, Larynx. Nih.gov; StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK538202