Arytenoid cartilage

At a glance

English

Arytenoid cartilage

Latin (TA2)

Cartilago arytenoidea

System

Cartilage

Region

Neck

Side

Paired, left and right

About the arytenoid cartilage

The arytenoid cartilages are two small cartilages at the back of the larynx, sitting side by side on the upper border of the cricoid lamina. Each is shaped like a three-sided pyramid; the name comes from a Greek word for a ladle. It has a base below, an apex above and three faces: posterior, medial and anterolateral. The vocal ligament, the core of the vocal fold, is fixed to the front of the base, so each arytenoid acts as the movable back anchor of one vocal fold.

The base carries a smooth, hollowed facet that rests on a matching facet on the cricoid, forming the synovial cricoarytenoid joint. Two angles project from it: the vocal process points forwards and takes the vocal ligament, and the muscular process juts backwards and outwards and takes the main muscles that move the cartilage. The apex curves backwards and towards the midline and is capped by the corniculate cartilage. The medial faces of the two cartilages look towards each other and bound the back part of the glottis; the posterior faces are covered by the arytenoid muscles; and the anterolateral face is marked by a curved crest and two shallow pits that give attachment to the vestibular and vocal structures.

Movements at the cricoarytenoid joint position the vocal folds. The cartilage can glide towards or away from its partner, rock forwards and backwards, and swivel about a vertical axis. Posterior cricoarytenoid pulls the muscular process back, turning the vocal processes apart and opening the glottis for breathing; lateral cricoarytenoid pulls it forwards, swinging the vocal processes together; and the transverse and oblique arytenoid muscles draw the two cartilages together to close the back of the glottis. These movements set whether the folds are open, closed, tense or relaxed, and so control breathing, voice and protection of the airway.

Rheumatoid arthritis or osteoarthritis can stiffen the cricoarytenoid joint and fix the folds near the midline, sometimes narrowing the airway dangerously. The cartilage may rarely be dislocated by a breathing tube, a laryngeal mask or a blow to the larynx, leaving a weak, breathy voice; it can be assessed with laryngeal electromyography and CT and pushed back into place endoscopically. On imaging, a sclerotic arytenoid strongly suggests laryngeal cancer.

Attachments and function

Attaches from

Its base articulates with the facet on the upper border of the cricoid lamina at the cricoarytenoid joint.

Attaches to

Anchors the vocal ligament at its vocal process, to the vestibular ligament on its anterolateral face, and to the cricoarytenoid, thyro-arytenoid and arytenoid muscles.

Function

Serves as the movable back anchor of each vocal fold; by gliding, tilting and rotating on the cricoid it opens and closes the glottis and alters vocal fold tension.

Nerve supply

The muscles moving it are supplied by the recurrent laryngeal nerve; the overlying mucosa above the vocal folds by the internal laryngeal nerve.

Blood supply

The laryngeal branches of the superior and inferior thyroid arteries supply the surrounding tissues and perichondrium.