The vocalis is the medial portion of the thyroarytenoid, forming the muscular core of the membranous vocal fold. It is the primary vibrating structure of voice production, with its mucosal cover (the epithelium and lamina propria) completing the layered vocal fold structure responsible for phonation.
| Origin | Inner surface of the thyroid cartilage angle — lower half, medial fibres of thyroarytenoid |
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| Insertion | Vocal process and lateral surface of the arytenoid cartilage |
| Nerve Supply | Recurrent laryngeal nerve (CN X) |
| Blood Supply | Laryngeal branch of inferior thyroid artery |
| Actions | Forms the body of the membranous vocal fold — the vibrating element of voice production; Selectively tenses segments of the vocal fold to adjust pitch and timbre; The medial vocalis fibres vibrate at 100-300 Hz during phonation |
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Vocalis scarring from vocal fold surgery, haemorrhage, or granuloma produces dysphonia by stiffening the vocal fold cover-body interface. Sulcus vocalis (a furrow in the vocal fold) involves vocalis surface changes producing a stiff, breathy voice. In professional voice users, even minor vocalis changes produce significant vocal quality deterioration. Laryngeal EMG of the vocalis assesses RLN integrity and predicts recovery from vocal fold paralysis.
Not externally palpable — assessed by laryngoscopy showing the vibrating vocal fold edge during phonation.
Post-operative vocalis fibrosis from cordectomy or vocal fold surgery producing stiffened vocal fold vibration, manifesting as a rough, breathy voice requiring steroid injection or microsurgical scar lysis.
