One facet is on the sloping superolateral surface of the lamina and articulates with the base of an arytenoid cartilage.
The other facet is on the lateral surface of the lamina near its base and is for articulation with the medial surface of the inferior horn of the thyroid cartilage.
The thyroid cartilage (Fig. 8.211) is the largest of the laryngeal cartilages. It is formed by a right and a left lamina, which are widely separated posteriorly, but converge and join anteriorly. The most superior point of the site of fusion between the two broad flat laminae projects forward as the laryngeal prominence (Adam’s apple). The angle between the two laminae is more acute in men (90°) than in women (120°) so the laryngeal prominence is more apparent in men than women.
Just superior to the laryngeal prominence, the superior thyroid notch separates the two laminae as they diverge laterally. Both the superior thyroid notch and the laryngeal prominence are palpable landmarks in the neck. There is a less distinct inferior thyroid notch in the midline along the base of the thyroid cartilage.
The posterior margin of each lamina of the thyroid cartilage is elongated to form a superior horn and an inferior horn:
The medial surface of the inferior horn has a facet for articulation with the cricoid cartilage.
The superior horn is connected by a lateral thyrohyoid ligament to the posterior end of the greater horn of the hyoid bone.
The lateral surface of each thyroid lamina is marked by a ridge (the oblique line), which curves anteriorly from the base of the superior horn to a little short of midway along the inferior margin of the lamina.
The ends of the oblique line are expanded to form superior and inferior thyroid tubercles. The oblique line is a site of attachment for the extrinsic muscles of the larynx (sternothyroid, thyrohyoid, and inferior constrictor).
The epiglottis is a leaf-shaped cartilage attached by its stem to the posterior aspect of the thyroid cartilage at the angle (Fig. 8.212) and projects posterosuperiorly from its attachment to the thyroid cartilage. The attachment is via the thyro-epiglottic ligament in the midline approximately midway between the laryngeal prominence and the inferior thyroid notch. The upper margin of the epiglottis is behind the pharyngeal part of the tongue.
The inferior half of the posterior surface of the epiglottis is raised slightly to form an epiglottic tubercle.
The two arytenoid cartilages are pyramid-shaped cartilages with three surfaces, a base of arytenoid cartilage and an apex of arytenoid cartilage (Fig. 8.213):
The base is concave and articulates with the sloping articular facet on the superolateral surface of the lamina of cricoid cartilage.
The apex articulates with a corniculate cartilage.
The medial surface of each cartilage faces the other.
The anterolateral surface has two depressions, separated by a ridge, for muscle (vocalis) and ligament (vestibular ligament) attachment.
The posterior surface is covered by the transverse arytenoid muscle (see Fig. 8.223).
The anterior angle of the base is elongated into a vocal process to which the vocal ligament is attached. The lateral angle is similarly elongated into a muscular process for attachment of the posterior and lateral crico-arytenoid muscles.
The corniculate cartilages (Fig. 8.214) are two small conical cartilages whose bases articulate with the apices of the arytenoid cartilages. Their apices project posteromedially toward each other.