Yes, the Larynx Contains Multiple Muscles
Yes, the larynx contains both intrinsic and extrinsic muscles that are essential for voice production, breathing, and airway protection. 1, 2, 3
Intrinsic Laryngeal Muscles
The intrinsic laryngeal muscles are specialized striated muscles located within the larynx itself that control vocal cord movement and tension:
All intrinsic laryngeal muscles except the cricothyroid receive motor innervation from the recurrent laryngeal nerve (RLN). 1, 2
The cricothyroid muscle is the sole exception, receiving innervation from the external branch of the superior laryngeal nerve. 4
These muscles are bilaterally arranged and functionally grouped as adductors and abductors of the glottis and tensors of the vocal cords. 4
The posterior cricoarytenoid muscle is the primary muscle that opens the laryngeal airway, while the cricothyroid works together with it to accentuate this opening. 3
The thyroarytenoid/lateral cricoarytenoid complex represents key intrinsic muscles commonly examined during laryngeal electromyography. 1
Extrinsic Laryngeal Muscles
Extrinsic muscles connect the larynx to surrounding structures and control laryngeal position:
Opening muscles include the geniohyoid, mylohyoid, sternothyroid, and middle constrictor. 3
Closing muscles include the thyrohyoid, cricothyroid, sternohyoid, and inferior constrictor. 3
The suprahyoid muscles play a critical role in swallowing by elevating the larynx and opening the upper esophageal sphincter. 1
Additional Laryngeal Musculature
The cricopharyngeus muscle receives motor innervation from the RLN and is positioned posterior to the thyroid gland adjacent to the esophagus. 5, 2
The inferior constrictor also receives innervation from the RLN. 2
Clinical Significance
Motor neurons controlling intrinsic laryngeal muscles are located in the nucleus ambiguus in the medulla. 1, 4
Laryngeal motor fibers within the RLN have a 4 to 1 adductor to abductor ratio. 2
These muscles contain a greater percentage of type 1 (slow-twitch) fibers compared to limb skeletal muscles, reflecting their specialized function for sustained phonation and airway control. 4
Dysfunction of laryngeal muscles can occur in conditions such as vocal cord paralysis, spasmodic dysphonia, Parkinson disease, and muscular tension dysphonia. 1, 3