The transverse arytenoid (interarytenoid) muscle is the only unpaired intrinsic laryngeal muscle. It connects the posterior surfaces of the two arytenoid cartilages horizontally, drawing them together to close the posterior commissure of the glottis. Closure of the posterior glottis is essential for phonation and for protection of the airway during swallowing.
| Origin | Posterior surface and muscular process of one arytenoid cartilage |
|---|---|
| Insertion | Corresponding surfaces of the opposite arytenoid cartilage |
| Nerve Supply | Recurrent laryngeal nerve (CN X) |
| Blood Supply | Superior and inferior laryngeal arteries |
| Actions | Adducts the arytenoid cartilages (closes the posterior glottis during phonation and swallowing) |
|---|
The transverse arytenoid is one of the muscles assessed during laryngoscopy in patients with dysphonia. Because it is unpaired and receives bilateral recurrent laryngeal nerve supply, it is less affected by unilateral RLN palsy than the paired intrinsic laryngeal muscles. Posterior glottic stenosis, a complication of prolonged intubation, involves scarring and fibrosis that fixes the posterior commissure in the closed position, and surgical correction requires posterior cordotomy or arytenoidectomy that traverses this muscle.
Not directly palpable; assessed indirectly by laryngoscopy.
Prolonged endotracheal intubation causes ischaemic necrosis and fibrosis of the posterior commissure including the transverse arytenoid region, producing a fixed posterior glottic web that restricts vocal fold abduction, causing bilateral vocal fold immobility managed by endoscopic posterior cordotomy or laser division.
