The vocalis muscle is the medial portion of the thyroarytenoid muscle, running parallel to and directly underlying the vocal ligament. Its fibres are oriented along the vocal fold and can contract selectively to vary the tension and thickness of different portions of the vocal fold independently, providing the fine motor control necessary for subtle pitch adjustments during speech and singing. It is sometimes regarded as the most sophisticated muscle in the body in terms of its precise neuromuscular control.
| Origin | Inner surface of the thyroid cartilage at the angle, alongside the thyroarytenoid |
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| Insertion | Vocal process and adjacent vocal ligament of the arytenoid cartilage |
| Nerve Supply | Recurrent laryngeal nerve (CN X) |
| Blood Supply | Superior laryngeal artery |
| Actions | Selectively tenses specific portions of the vocal fold for fine pitch control; Shortens and thickens the vocal fold to lower pitch (antagonising the cricothyroid) |
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The vocalis muscle is the innermost layer of the vocal fold and is critical for voice production. Vocal fold polyps, nodules, and Reinke oedema affect the superficial lamina propria just above the vocalis. Laryngeal surgery must respect the vocalis to avoid producing a sulcus vocalis (a scar tract between the mucosa and the muscle) that produces a breathy, dysphonic voice. Injection laryngoplasty for vocal fold paralysis targets the vocalis to medialise the paralysed fold and restore vocal fold approximation.
Not externally palpable; visualised by laryngoscopy and assessed by stroboscopy.
A scar tract binding the vocal fold mucosa to the underlying vocalis muscle, produced by overzealous laryngeal microsurgery, vocal fold trauma, or laryngeal lesion removal, causes a stiff, breathy dysphonia that is difficult to treat and best avoided by conservative surgical technique.
Recurrent laryngeal nerve palsy denervates the vocalis and other intrinsic laryngeal muscles, causing a flaccid, lateralised vocal fold with a breathy, weak voice and aspiration risk, managed by injection laryngoplasty with hyaluronic acid or hydroxylapatite, or surgical medialisation thyroplasty.
