Head and neck muscles (chewing, facial, and throat muscles)

External part of thyroarytenoid

Musculus thyroarytenoideus, pars externa

Origin

Inner surface of the lamina of the thyroid cartilage, near the angle

Insertion

Muscular process and lateral surface of the arytenoid cartilage

Function

Adducts and shortens/relaxes the vocal fold, assisting glottic closure

Innervation

Recurrent laryngeal nerve (branch of the vagus nerve, CN X)

Movement & chain

Works together with the internal part (vocalis) and lateral cricoarytenoid in fine control of vocal fold tension during phonation.

Palpation

Not palpable externally; located within the inner lamina of the thyroid cartilage.

Clinical

Unilateral recurrent laryngeal nerve palsy results in a paralyzed, non-adducting vocal fold with a hoarse voice (dysphonia).

Segmental innervation

Vagus nerve (X), motor via the recurrent laryngeal nerve.

In clinical practice

Relaxes vocal folds to lower pitch; speech-language pathology voice therapy for functional dysphonia.

Region in the model

Head and neck muscles (chewing, facial, and throat muscles)