Laryngeal muscles

The laryngeal muscles are divided into intrinsic and extrinsic groups based on their attachments and primary functions. Together, they control the movement of the larynx during phonation, breathing, and swallowing, and regulate the tension and position of the vocal folds.

1. Extrinsic Muscles

These muscles attach the larynx to surrounding structures, moving it as a whole during swallowing or speech. They are classified as elevators or depressors of the larynx.

A. Elevators (laryngeal elevators)

These include the suprahyoid muscles (stylohyoid, mylohyoid, geniohyoid, and digastric) and the longitudinal pharyngeal muscles (stylopharyngeus, palatopharyngeus, and salpingopharyngeus).

B. Depressors (laryngeal depressors)

These include the infrahyoid muscles (sternothyroid, sternohyoid, omohyoid, and thyrohyoid).

These draw the larynx downward after elevation, helping restore it to its resting position.

2. Intrinsic Muscles

The intrinsic laryngeal muscles are responsible for fine control of the vocal folds and glottic aperture. They act on the arytenoid, cricoid, and thyroid cartilages to regulate tension, length, and position of the vocal folds during phonation, respiration, and protection of the airway.

These include: Cricothyroid, posterior cricoarytenoid, lateral cricoarytenoid, thyroarytenoid, oblique arytenoid, transverse arytenoid)

All intrinsic laryngeal muscles are supplied by the recurrent laryngeal nerve (branch of vagus nerve, CN X), except the cricothyroid, which is supplied by the external branch of the superior laryngeal nerve (also from CN X). Recurrent laryngeal nerve injury (e.g., during thyroid or neck surgery) may cause vocal fold paralysis, leading to hoarseness, dysphonia, or airway compromise.