The thyroarytenoid contains the vocalis (thyrovocalis) as its medial portion — the muscle that forms the body of the vocal fold. The lateral portion (thyromuscularis) adducts and stabilises the arytenoid. Botulinum injection of the thyroarytenoid is the primary treatment for adductor spasmodic dysphonia.
| Origin | Inner surface of the thyroid cartilage angle — lower half |
|---|---|
| Insertion | Muscular process of the arytenoid cartilage and vocal process |
| Nerve Supply | Recurrent laryngeal nerve (RLN — branch of CN X) |
| Blood Supply | Laryngeal branch of inferior thyroid artery |
| Actions | Adducts and shortens the vocal folds — the primary vocal fold closer; The thyrovocalis portion forms the body of the vocal fold |
|---|
Thyroarytenoid botulinum injection for adductor spasmodic dysphonia produces 3-4 months of relief from the strained, strangled voice characteristic of this condition. The injection is guided by EMG through the cricothyroid membrane. RLN injury during thyroidectomy denervates the thyroarytenoid, producing vocal fold paralysis.
Not externally palpable — assessed by laryngoscopy showing vocal fold motion and botulinum response.
EMG-guided thyroarytenoid botulinum injection producing 3-4 months of improved voice quality in adductor spasmodic dysphonia.
