Ultrasonography of the cricoarytenoid joint and its movements

Ultrasound provides real-time anatomical information and motion. We used ultrasound to image the cricoarytenoid joint and its rotating, rocking, and gliding movements.

Between March and October 2023, 20 patients (10 males and 10 females) who visited our hospital underwent laryngeal ultrasonography. The joint cavity was delineated in four patients (20 %, two males and two females). Conversely, the other patients did not detect it because of acoustic shadows on ultrasonography. We also performed ultrasonography on five volunteers (three males and two females), but only two of them (two females) showed imaging of the joint cavity. Herein, we report the case of a female volunteer in her 30 s who had the best delineation of joint movements.

Joint movements were three-dimensional, whereas ultrasound images were two-dimensional. However, combined with scanning techniques, characteristic joint movements were successfully imaged using ultrasound. Initially, we performed a trans-thyroid cartilage transversal procedure to visualize the muscular process of the arytenoid cartilage and rotational movement. Subsequently, the probe was rotated to an oblique position, and the articular cavity of the cricoarytenoid joint was visualized. We then observed the rocking and gliding movements. In Addition, we demonstrated a seamless transition from gliding to rocking. Finally, we observed that the arytenoid cartilage was pulled toward the posterior cricoarytenoid muscle (PCA) during sniffing. The PCA is the only muscle opening the vocal cords, so the arytenoid cartilage shifts toward the PCA and tilts outward from the larynx.

The presented probe scanning techniques and specific joint movements may help identify notable conditions such as arthritis or joint dislocation.