The larynx (voice box) is an organ located in the anterior neck. It is a component of the respiratory tract, and has several important functions, including phonation, the cough reflex, and protection of the lower respiratory tract. There are nine cartilages located within the larynx; three unpaired, and six paired. They form the laryngeal skeleton, which provides rigidity and stability. In this article, we shall examine the anatomy of the laryngeal cartilages.
The three unpaired cartilages are the epiglottis, thyroid and cricoid cartilages.
The thyroid cartilage is a large, prominent structure which is easily visible in adult males. It is composed of two sheets (laminae), which join anteriorly to form the laryngeal prominence (Adam’s apple).
The posterior border of each sheet project superiorly and inferiorly to form the superior and inferior horns (also known as cornu). The superior horns are connected to the hyoid bone via the lateral thyrohyoid ligament, while the inferior horns articulate with the cricoid cartilage.
The cricoid cartilage is a complete ring of hyaline cartilage, consisting of a broad sheet posteriorly and a much narrower arch anteriorly (said to resemble a signet ring in shape).
The cartilage completely encircles the airway, marking the inferior border of the larynx at the level of C6. It articulates with the paired arytenoid cartilages posteriorly, as well as providing an attachment for the inferior horns of the thyroid cartilage.
The cricoid is the only complete circle of cartilage in the larynx or trachea. This is of clinical relevance during emergency intubation – as pressure can be applied to the cricoid to occlude the oesophagus, and thus prevent regurgitation of gastric contents (known as cricoid pressure or Sellick’s manoeuvre).
The epiglottis is a leaf shaped plate of elastic cartilage which marks the entrance to the larynx. Its 'stalk' is attached to the back of the anterior aspect of the thyroid cartilage. During swallowing, the epiglottis flattens and moves posteriorly to close off the larynx and prevent aspiration.
There are three paired cartilages – the arytenoid, corniculate and cuneiform. They are situated bilaterally in the larynx.
The arytenoid cartilages are pyramidal shaped structures that sit on the cricoid cartilage. They consist of an apex, base, three sides and two processes, and provides an attachment point for various key structures in the larynx-
The corniculate cartilages are minor cartilaginous structures. They articulate with the apices of the arytenoid cartilages.
The cuneiform cartilages are located within the aryepiglottic folds. They have no direct attachment, but act to strengthen the folds.
The posterior border of each sheet project superiorly and inferiorly to form the superior and inferior horns (also known as cornu). The superior horns are connected to the hyoid bone via the lateral thyrohyoid ligament, while the inferior horns articulate with the cricoid cartilage.
The cricoid cartilage is a complete ring of hyaline cartilage, consisting of a broad sheet posteriorly and a much narrower arch anteriorly (said to resemble a signet ring in shape). The cartilage completely encircles the airway, marking the inferior border of the larynx at the level of C6. It articulates with the paired arytenoid cartilages posteriorly, as well as providing an attachment for the inferior horns of the thyroid cartilage.
The cricoid is the only complete circle of cartilage in the larynx or trachea. The uniquness of this cartilage makes it clinically relevant during emergency intubation. Pressure can be applied to the cricoid to occlude the oesophagus, and thus preventing regurgitation of gastric contents (known as cricoid pressure or Sellick's manoeuvre). This technique is used in resuscitation to protect the patient from aspiration.
The epiglottis is a leaf shaped plate of elastic cartilage which marks the entrance to the larynx. Its 'stalk' is attached to the back of the anterior aspect of the thyroid cartilage. It is an important structure that plays a role in normal swallowing. When we swallow, the epiglottis flattens and moves posteriorly to close off the larynx and prevent aspiration.
There are three paired cartilages – the arytenoid, corniculate and cuneiform. They are situated bilaterally in the larynx.
The arytenoid cartilages are pyramidal shaped structures that sit on the cricoid cartilage. They consist of an apex, base, three sides and two processes, and provides an attachment point for various key structures in the larynx. The apex articulates with the corniculate cartilage, the base with the superior border of the cricoid cartilage, while the vocal process provides attachment for the vocal ligament and the muscular process provides attachment for the posterior and lateral cricoarytenoid muscles.
The corniculate cartilages are minor cartilaginous structures. They articulate with the apices of the arytenoid cartilages.
The cuneiform cartilages are located within the aryepiglottic folds. They have no direct attachment, but act to strengthen the folds.
In conclusion, the larynx is a complex organ, composed of nine cartilages. These cartilages form the laryngeal skeleton, providing rigidity and stability, while also playing an important part in phonation, the cough reflex, and protection of the lower respiratory tract. Both the unpaired and paired cartilages serve their own functions, with the cricoid cartilage being of particular interest during emergency intubation, due to its ability to occlude the oesophagus and prevent regurgitation of gastric contents.
During swallowing, the epiglottis flattens and moves posteriorly to close off the larynx and prevent aspiration. In the larynx, there are three paired cartilages that are situated bilaterally and together aid in the process of swallowing. These cartilages are the arytenoid, corniculate and cuneiform cartilages. Each of these cartilages is unique in its structure and purpose and together work in harmony with the larynx to ensure seamless swallowing with no aspiration.
The arytenoid cartilages are pyramidal-shaped structures that sit on the cricoid cartilage. Each arytenoid cartilage has an apex, base, three sides and two processes that serve to attach to other structures in the larynx. Specifically, the apex of the cartilage articulates with the corniculate cartilage, the base articulates with the superior border of the cricoid cartilage, the vocal process provides attachment for the vocal ligament, and the muscular process provides attachment for the posterior and lateral cricoarytenoid muscles. All of these components work in unison to facilitate proper swallowing and bring about the flattening and posterior movement of the epiglottis.
The corniculate cartilages are minor cartilaginous structures that work together with the arytenoid cartilages to achieve proper swallowing. They articulate with the apices of the arytenoid cartilages, providing support to maintain the shape of the aryepiglottic folds necessary for efficient swallowing.
The cuneiform cartilages are located within the aryepiglottic folds and have no direct attachment. However, they act as support structures and strengthen the folds in order to keep them in the proper shape for swallowing and to help prevent aspiration.
The three paired cartilages of the larynx, the arytenoid, corniculate and cuneiform cartilages, are indispensable to the process of swallowing. Through their unique structures and functions, the vocal process, muscular process and corniculate cartilages all contribute to the proper functioning of swallowing by facilitating the flattening and posterior movement of the epiglottis. Together, they act in harmony to ensure proper functioning with no aspiration.
