Learning objective
By the end of this article, the learner should be able to identify and describe the laryngeal cartilages, including their classification, anatomical features, and functional significance.
Overview of the larynx
The larynx (voice box) is an organ located in the anterior region of the neck. It forms part of the respiratory tract and performs several essential functions, including phonation, initiation of the cough reflex, and protection of the lower respiratory tract during swallowing.
The structural framework of the larynx is formed by nine cartilages, collectively known as the laryngeal skeleton. These cartilages provide rigidity, maintain airway patency, and serve as attachment sites for muscles and ligaments involved in breathing and voice production.
The laryngeal cartilages are classified into three unpaired and three paired cartilages.
In this article, we will examine the anatomy of the laryngeal cartilages, highlighting their structure and functional relevance.
Unpaired cartilages
The three unpaired cartilages of the larynx are the thyroid, cricoid, and epiglottic cartilages.
Thyroid cartilage
The thyroid cartilage is the largest laryngeal cartilage and is easily palpable and visible in many adult males. It is formed by two quadrilateral plates (laminae) that fuse anteriorly to create the laryngeal prominence (Adam’s apple).
Posteriorly, each lamina extends superiorly and inferiorly to form the superior and inferior horns (cornua):
- The superior horns are connected to the hyoid bone by the lateral thyrohyoid ligaments
- The inferior horns articulate with the cricoid cartilage at the cricothyroid joints
The thyroid cartilage protects the vocal cords and serves as an attachment site for intrinsic and extrinsic laryngeal muscles.
Cricoid cartilage
The cricoid cartilage is a complete ring of hyaline cartilage and forms the inferior boundary of the larynx at the level of C6. It consists of:
- A broad posterior lamina
- A narrow anterior arch, giving it a signet-ring appearance
The cricoid cartilage articulates:
- Superiorly with the paired arytenoid cartilages
- Superolaterally with the inferior horns of the thyroid cartilage
It is the only complete cartilaginous ring in the larynx and trachea. This feature is clinically significant, as pressure applied to the cricoid cartilage can compress the oesophagus during emergency airway management, reducing the risk of aspiration (cricoid pressure or Sellick’s manoeuvre).
Epiglottis
The epiglottis is a leaf-shaped plate of elastic cartilage that forms the superior boundary of the laryngeal inlet. Its inferior stalk (petiolus) attaches to the inner surface of the thyroid cartilage.
During swallowing, the epiglottis moves posteriorly and inferiorly to cover the laryngeal inlet, preventing aspiration of food and liquids into the airway.
Paired cartilages
There are three paired cartilages in the larynx:
- Arytenoid cartilages
- Corniculate cartilages
- Cuneiform cartilages
These structures are located bilaterally and play a key role in vocal cord movement and laryngeal stability.
Arytenoid cartilages
The arytenoid cartilages are pyramidal structures that sit on the superior border of the cricoid cartilage. Each arytenoid has:
- An apex, which articulates with the corniculate cartilage
- A base, which articulates with the cricoid cartilage
- A vocal process, providing attachment for the vocal ligament
- A muscular process, providing attachment for the posterior and lateral cricoarytenoid muscles
These cartilages are essential for controlling the abduction and adduction of the vocal cords.
Corniculate cartilages
The corniculate cartilages are small, conical cartilages that articulate with the apices of the arytenoid cartilages. They contribute to the structural support of the posterior laryngeal inlet.
Cuneiform cartilages
The cuneiform cartilages are elongated cartilages embedded within the aryepiglottic folds. Although they do not articulate directly with other cartilages, they act to strengthen and support the folds, maintaining patency of the laryngeal inlet.
