Laryngeal joints

The laryngeal joints (Joints of larynx) comprise two paired of synovial joints (the cricoarytenoid joint and the cricothyroid joint) and some fibrous joints.

Synovial joints of larynx

• The cricoarytenoid joint is a diarthrodial (synovial) joint formed between the articular facet on the superior surface of the cricoid cartilage lamina and the base of the arytenoid cartilage. The cricoid facet is typically convex in the anteroposterior direction, while the arytenoid facet is concave, though significant intra- and inter-individual morphological variation exists. The joint is enclosed by a connective-elastic articular capsule that bounds a synovial cavity containing synovial folds a short medial fold and longer lateral folds as well as deep peripheral blind recesses, all indicative of great articular mobility. The capsule is strengthened by the posterior cricoarytenoid ligament, a flattened band of fibers on the medial aspect. Additional ligaments described include the anterior and posterior capsular ligaments, which contribute to joint stability.

• The cricothyroid joint (CTJ) is a synovial joint formed between the inferior cornu (horn) of the thyroid cartilage and the lateral facet of the cricoid cartilage. It is supported by two ligaments the lateral and posterior ceratocricoid ligaments and an articular capsule.

Fibrous joints of larynx

• Thyrohyoid membrane: Connects the upper border of the thyroid cartilage to the hyoid bone. Thickened centrally as the median thyrohyoid ligament and laterally as the paired lateral thyrohyoid ligaments (each containing a small cartilago triticea). Pierced by the internal laryngeal nerve and superior laryngeal vessels.

• Ligaments of epiglottis: Comprises the hyoepiglottic ligament (epiglottis to hyoid body, suspending the epiglottis) and the thyroepiglottic ligament (petiolus of epiglottis to the inner thyroid cartilage angle, anchoring it inferiorly).

• Fibroelastic membrane of larynx: Internal elastic framework of the larynx, made up of the quadrangular membrane superiorly (epiglottis to arytenoid, free edge forms the aryepiglottic fold above and vestibular ligament below) and the conus elasticus inferiorly (free edge forms the vocal ligament, base forms the median cricothyroid ligament).

• Median cricothyroid ligament: Thickened anterior midline part of the conus elasticus, connecting the arch of the cricoid cartilage to the lower border of the thyroid cartilage. Key surgical landmark for cricothyrotomy.

• Cricotracheal ligament: Fibrous band linking the lower border of the cricoid cartilage to the first tracheal ring, continuing the airway's fibroelastic support into the trachea.