Anatomy, Head and Neck: Laryngeal Muscles

Excerpt

The laryngeal muscles are critical to voice production, breathing, and airway protection during swallowing. These muscles are categorized into intrinsic and extrinsic based on their location and function (see Image. Laryngeal Muscles).

Intrinsic laryngeal muscles are confined within the larynx and are primarily responsible for controlling sound production by adjusting the vocal cords' tension, length, and position. The primary intrinsic muscles include the cricothyroid, thyroarytenoid, lateral and posterior cricoarytenoid, and interarytenoid muscles. These muscles are innervated by branches of the vagus nerve, particularly the recurrent laryngeal nerve (RLN). The cricothyroid is the exception, as this muscle is innervated by the external branch of the superior laryngeal nerve (SLN).

On the other hand, extrinsic laryngeal muscles have one attachment site outside the larynx and play a role in positioning and stabilizing the larynx during swallowing and speech. These muscles include the suprahyoid muscles, including the digastric, stylohyoid, mylohyoid, and geniohyoid, and the infrahyoid muscles, including the sternohyoid, sternothyroid, thyrohyoid, and omohyoid. The suprahyoid muscles elevate the larynx, while the infrahyoid muscles depress the larynx.

The intricate coordination of these muscles ensures that the larynx functions effectively during phonation and airway protection. Surgical interventions involving the laryngeal muscles and nerves require a detailed understanding of their anatomy and innervation to prevent complications such as voice changes and aspiration.