The larynx, often referred to as the “voice box,” plays a vital role not only in speech but also in respiration and airway protection. For respiratory therapists and professionals working in respiratory care, a thorough understanding of the larynx is essential.
This structure serves as a critical juncture between the upper and lower airways and is involved in functions ranging from ventilation to airway defense. Whether managing intubation, assessing airway obstructions, or treating respiratory diseases, the larynx is a central point of focus.
This article provides an overview of the larynx, its anatomy and function, and explains why it’s so important in respiratory therapy and critical care settings.
What Is the Larynx?
The larynx is a hollow, muscular organ located in the neck, situated between the pharynx (throat) and the trachea (windpipe). It is composed of cartilage, muscle, and connective tissue and is covered internally by mucous membrane. The most prominent external part of the larynx is the thyroid cartilage, commonly known as the Adam’s apple.
Functions of the Larynx
The larynx has three major functions:
- Respiration – It acts as a passageway for air moving into and out of the trachea and lungs.
- Phonation – It houses the vocal cords, which vibrate to produce sound when air is expelled from the lungs.
- Airway Protection – It prevents food and liquid from entering the lower respiratory tract during swallowing, thanks to the epiglottis, a flap-like structure that covers the glottis (opening of the larynx).
Anatomy of the Larynx
The larynx is composed of several key cartilaginous structures:
- Thyroid cartilage – the largest cartilage, forms the front wall of the larynx.
- Cricoid cartilage – a ring-shaped structure located below the thyroid cartilage; the only complete ring of cartilage in the airway.
- Epiglottis – leaf-shaped cartilage that protects the airway during swallowing.
- Arytenoid cartilages – paired cartilages that control vocal cord movement.
- Vocal folds (cords) – tissues that vibrate to produce sound.
Note: These structures are supported and moved by a network of intrinsic and extrinsic muscles, all innervated mainly by branches of the vagus nerve (cranial nerve X), specifically the recurrent laryngeal nerve and superior laryngeal nerve.
Importance of the Larynx in Respiratory Therapy
Respiratory therapists encounter the larynx frequently in both routine and emergency care. Its relevance spans multiple areas of practice:
1. Airway Management
The larynx is a crucial landmark during endotracheal intubation, a life-saving procedure where a tube is inserted through the mouth or nose into the trachea to maintain an open airway. Accurate visualization of the vocal cords within the larynx is essential to avoid trauma and ensure proper tube placement.
Additionally, conditions such as laryngeal edema, vocal cord paralysis, or laryngospasm (sudden closure of the vocal cords) can complicate airway management and require rapid intervention by skilled respiratory personnel.
2. Mechanical Ventilation
The endotracheal tube or tracheostomy tube often passes through or bypasses the larynx during mechanical ventilation. This can lead to laryngeal injury, vocal cord damage, or stenosis (narrowing), especially with prolonged intubation.
Respiratory therapists play a key role in minimizing these risks by ensuring proper tube care and monitoring for signs of laryngeal compromise.
3. Voice and Breathing Assessment
Changes in voice (e.g., hoarseness) or breathing sounds (e.g., stridor) can indicate laryngeal pathology. Recognizing these signs enables respiratory therapists to identify airway obstruction, vocal cord dysfunction, or inflammation early, thereby prompting timely referrals and interventions.
4. Pediatric Respiratory Care
In infants and children, the larynx is higher and narrower, making it more susceptible to obstruction. Conditions such as croup (viral laryngotracheobronchitis) and laryngomalacia (floppy laryngeal structures) are common pediatric airway disorders that respiratory therapists must be familiar with.
Clinical Conditions Involving the Larynx
Several conditions affecting the larynx are highly relevant in respiratory care:
- Laryngitis – Inflammation often due to infection or irritation, leading to hoarseness and cough.
- Laryngeal cancer – Can obstruct the airway and require surgical removal, possibly leading to tracheostomy.
- Laryngospasm – A reflex closure of the vocal cords, often seen during anesthesia or GERD, causing acute respiratory distress.
- Obstructive sleep apnea – May involve collapse of the upper airway, including the laryngeal structures.
- Trauma – Blunt or penetrating trauma can injure the larynx, affecting airway patency and voice.
Role of the Respiratory Therapist
Respiratory therapists must understand the larynx not only anatomically, but also functionally and clinically. Their responsibilities often include:
- Assisting with intubation and ensuring proper placement
- Managing and troubleshooting airway equipment
- Recognizing early signs of laryngeal injury or dysfunction
- Collaborating with ENT specialists, speech-language pathologists, and critical care teams
- Educating patients about vocal hygiene and breathing techniques, particularly post-extubation
Larynx Practice Questions
1. What is the larynx commonly referred to as?
The voice box.
2. To which structure is the larynx attached superiorly?
The hyoid bone.
3. What structure is the larynx continuous with inferiorly?
The trachea.
4. What are the primary functions of the larynx?
Maintaining an open airway, directing air and food into proper channels, and enabling voice production.
5. How many cartilages form the framework of the larynx?
Nine cartilages connected by membranes and ligaments.
6. What type of cartilage comprises most of the larynx?
Hyaline cartilage, except for the epiglottis which is elastic cartilage.
7. What type of epithelium lines the superior portion of the larynx?
Stratified squamous epithelium.
8. Which three small paired cartilages contribute to the lateral and posterior walls of the larynx?
The cuneiform, corniculate, and arytenoid cartilages.
9. Which laryngeal cartilage anchors the vocal cords?
The arytenoid cartilage.
10. What is the name of the spoon-shaped, ninth cartilage of the larynx?
The epiglottis.
11. What is the epiglottis composed of, and what is its surface covering?
Elastic cartilage covered by taste bud-containing mucosa.
12. Where does the epiglottis extend from and to?
From the posterior tongue to the anterior rim of the thyroid cartilage.
13. What occurs when air flows into the larynx?
The inlet remains open, and the epiglottis stands upright, allowing airflow.
14. What happens to the larynx during swallowing?
The larynx elevates and the epiglottis folds down to cover the laryngeal inlet.
15. What are the vocal ligaments made of?
Elastic fibers.
16. Why do the vocal cords appear pearly white?
They lack blood vessels.
17. What is the function of the false vocal cords (vestibular folds)?
They help close the glottis during swallowing.
18. What type of epithelium is found below the vocal cords?
Pseudostratified ciliated columnar epithelium.
19. What are the three major functions of the larynx?
To act as an air passage, prevent aspiration, and produce sound.
20. True or False: The laryngeal skeleton consists of 8 cartilages—2 paired and 4 unpaired.
False. It consists of 9 cartilages—3 paired and 3 unpaired.
21. True or False: The laryngeal cartilages are connected by membranes.
True
22. What are the three unpaired cartilages of the laryngeal skeleton?
Thyroid, cricoid, and epiglottis.
23. Describe the structure of the thyroid cartilage.
It consists of two laminae that fuse anteriorly to form the Adam’s apple (laryngeal prominence).
24. What is the cricoid cartilage?
It is shaped like a signet ring and sits at the C6 level, with its broad part posteriorly.
25. How is the epiglottis anchored in the larynx?
It is attached to the thyroid cartilage internally and to the posterior tongue via glossoepiglottic folds.
26. What is the function of the thyrohyoid membrane?
It connects the thyroid cartilage to the hyoid bone and transmits the internal branch of the superior laryngeal nerve.
27. What does the cricothyroid ligament connect?
It spans from the anterior cricoid cartilage to the thyroid cartilage.
28. What are the three paired cartilages of the larynx?
Arytenoid, corniculate, and cuneiform cartilages.
29. What is the function and structure of the arytenoid cartilages?
They are pyramid-shaped structures that sit on the cricoid cartilage and anchor the vocal and muscular processes.
30. What is the role of the corniculate cartilages?
They sit on top of the arytenoids and assist in lengthening and stabilizing the vocal processes.
31. What are the cuneiform cartilages, and where are they located?
Small, club-shaped cartilages embedded in the aryepiglottic folds.
32. True or False: The larynx is lined by respiratory mucosa.
True.
33. True or False: The false vocal cords are located inferior to the true vocal cords.
False; they are located superior to the true vocal cords.
34. True or False: The vestibular folds are involved in phonation.
False; they serve as a protective mechanism, not for sound production.
35. What forms the true vocal cords?
Mucosa covering the vocal ligaments and the vocalis muscles.
36. What is the rima glottidis?
The opening between the right and left vocal folds.
37. What are the three internal regions of the larynx?
The vestibule, ventricle, and infraglottic cavity.
38. What is the infraglottic cavity, and where does it extend?
The area below the vocal cords, extending to the inferior border of the cricoid cartilage.
39. What is the quadrangular membrane, and what does it form?
A membrane from the lateral epiglottis to the arytenoids; its upper edge forms the aryepiglottic fold, and the lower edge forms the vestibular (false vocal) fold.
40. What structure fills the triangular area between the true vocal folds and the cricoid cartilage?
The cricothyroid membrane.
41. What are extrinsic laryngeal muscles and their function?
Muscles that attach outside the larynx and move it as a whole, such as during swallowing or phonation.
42. What are the intrinsic laryngeal muscles, and what do they do?
Muscles that originate and insert within the larynx to control vocal cord movement.
43. What are the intrinsic muscles of the larynx and their main actions?
Lateral cricoarytenoid: adducts vocal folds, posterior cricoarytenoid: abducts vocal folds, oblique & transverse arytenoids: adduct vocal folds, thyroarytenoid: relaxes vocal cords, vocalis: fine-tunes vocal fold tension, and cricothyroid: tenses vocal cords, raising pitch.
44. Which cranial nerve innervates all intrinsic muscles of the larynx?
The vagus nerve (cranial nerve X).
45. What are the two branches of the superior laryngeal nerve and their roles?
The internal branch provides sensory input above the vocal folds; the external branch innervates the cricothyroid muscle.
46. How does the internal laryngeal nerve enter the larynx?
By piercing the thyrohyoid membrane.
47. Which nerves provide motor innervation to laryngeal muscles?
The recurrent laryngeal nerve (all intrinsic muscles except cricothyroid); the external laryngeal nerve (cricothyroid only).
48. Which nerves provide sensory innervation to the larynx?
The internal laryngeal nerve (above vocal folds) and the recurrent laryngeal nerve (below vocal folds).
49. True or False: The recurrent laryngeal nerves provide both sensory and motor innervation to the larynx.
True
50. What arteries supply blood to the larynx?
The superior laryngeal artery (from the superior thyroid artery) and the inferior laryngeal artery (from the inferior thyroid artery).
51. What does the larynx connect, and what is it specialized for?
Connects the inferior pharynx to the trachea; specialized for sound production, maintaining an open airway, and protecting the airway during swallowing.
52. At what vertebral levels is the larynx located?
From C3 to C6.
53. What occurs at the level of C6 in relation to the larynx?
The larynx transitions into the trachea.
54. What three structures are found at the level of C3?
The epiglottis, hyoid bone, and the superior border of the larynx.
55. At what vertebral level does the common carotid artery typically bifurcate?
Around the level of C5.
56. What lies anterior, lateral, and posterior to the larynx?
Anterior: infrahyoid muscles; Lateral: thyroid gland and carotid sheath; and Posterior: laryngopharynx.
57. How many cartilages form the larynx, and how are they grouped?
Nine cartilages: three unpaired (thyroid, cricoid, epiglottis) and three paired (arytenoid, corniculate, cuneiform).
58. True or False: The hyoid bone is part of the larynx.
False; it supports and connects to the larynx but is not part of it.
59. What is the role of the hyoid bone in relation to the larynx?
It anchors the larynx and facilitates its upward movement during swallowing, but it is not part of the larynx.
60. Which is the largest cartilage of the larynx?
The thyroid cartilage.
61. Which cartilage forms a complete ring around the larynx?
The cricoid cartilage.
62. Which cartilages are located anteriorly in the larynx?
The thyroid and cricoid cartilages.
63. What is the main surface area of the thyroid cartilage called?
The lamina.
64. What structure is referred to as the “Adam’s apple,” and in whom is it more prominent?
The laryngeal prominence; it is found in both males and females but is more prominent in males.
65. True or False: The Adam’s apple is only present in males.
False; it is present in both sexes but is more pronounced in males.
66. What is the thyroid notch?
A V-shaped indentation located just above the laryngeal prominence on the thyroid cartilage.
67. How does the thyroid cartilage articulate superiorly and inferiorly?
Superiorly with the hyoid bone via the superior horn; inferiorly with the cricoid cartilage via the inferior horn.
68. Which cartilage of the larynx is shaped like a signet ring?
The cricoid cartilage.
69. Which laryngeal cartilages are visible from a posterior view, and are they paired or unpaired?
Epiglottis (unpaired); cricoid cartilage (unpaired); and arytenoid, corniculate, and cuneiform cartilages (all paired).
70. What are the corniculate cartilages, and where are they located?
Paired cartilages that sit atop the apices of the arytenoid cartilages.
71. What are the cuneiform cartilages, and where are they found?
Paired cartilages embedded in the aryepiglottic folds between the epiglottis and arytenoid cartilages.
72. Which cartilage lies between the aryepiglottic folds?
The cuneiform cartilage.
73. Which cartilage sits on top of the apex of the arytenoid cartilage?
The corniculate cartilage.
74. Which cartilage is visible from a lateral view of the larynx?
The cricoid cartilage.
75. What is the region of the larynx located below the vocal cords called?
The infraglottic cavity.
76. What is the name of the space between the vestibular folds and vocal folds?
The laryngeal ventricle.
77. What is the opening between the vocal ligaments called?
The rima glottidis.
78. Which muscle is the primary tensor of the vocal ligaments?
The cricothyroid muscle.
79. Which laryngeal muscle is innervated by the external branch of the superior laryngeal nerve?
The cricothyroid muscle.
80. Which muscle increases vocal pitch and how?
The cricothyroid muscle by tensing the vocal ligaments.
81. Which muscle decreases vocal pitch and how?
The thyroarytenoid muscle by relaxing the vocal ligaments.
82. Which muscle enables whispering, and how is it innervated?
The lateral cricoarytenoid muscle; it adducts the vocal cords and is innervated by the recurrent laryngeal nerve.
83. What is the function, location, and innervation of the transverse and oblique arytenoid muscles?
They adduct the vocal cords to close the rima glottidis, are located posterior to the arytenoid cartilages, and are innervated by the recurrent laryngeal nerve.
84. Which muscles are responsible for closing the rima glottidis?
The lateral cricoarytenoid and both transverse and oblique arytenoid muscles.
85. What are the muscles of the larynx, their functions, and their innervation?
Cricothyroid: tenses vocal cords (external branch of superior laryngeal nerve); Thyroarytenoid: relaxes vocal cords (recurrent laryngeal nerve); Vocalis: fine-tunes vocal tension (recurrent laryngeal nerve); Posterior cricoarytenoid: abducts vocal cords (recurrent laryngeal nerve); Lateral cricoarytenoid: adducts vocal cords (recurrent laryngeal nerve); and Transverse and oblique arytenoids: fully adduct vocal cords (recurrent laryngeal nerve).
86. How does the larynx regulate pitch, tone, and volume of the voice?
By adjusting the tension, length, and position of the vocal folds and controlling airflow through muscular action.
87. What is the laryngeal aditus?
It is the superior opening of the larynx that connects it to the pharynx.
88. What is the vestibule of the larynx?
The area of the larynx located above the vestibular folds.
89. What is the rima vestibuli?
The space or opening between the vestibular (false vocal) folds.
90. What is the rima glottidis?
The opening between the right and left true vocal folds.
91. What controls the pitch of the voice?
Changes in the tension and length of the vocal folds and the width of the rima glottidis.
92. What is the glottis?
The glottis includes both the vocal folds and the rima glottidis.
93. What is the infraglottic cavity?
The portion of the larynx located below the true vocal folds, extending to the inferior border of the cricoid cartilage.
94. At which vertebral level is the cricoid cartilage located?
At the level of the C6 vertebra.
95. Against which structure can the carotid artery be compressed?
The C6 vertebra, using the cricoid cartilage as a landmark.
96. What junctions does the cricoid cartilage represent?
The larynx-trachea junction and the pharynx-esophagus junction.
97. Where is a tracheostomy typically performed?
Between the cricoid and first tracheal cartilage or between the cricoid and thyroid cartilages.
98. The thyroid cartilage is anterior to which cervical vertebrae?
C4 and C5.
99. What is the function of the superior horn of the thyroid cartilage?
It attaches to the hyoid bone via the lateral thyrohyoid ligament.
100. What is the function of the inferior horn of the thyroid cartilage?
It articulates with the cricoid cartilage to form part of the cricothyroid joint.
Final Thoughts
The larynx is far more than a voice-producing organ; it is a dynamic structure that protects the airway, enables breathing, and plays a pivotal role in patient care. For respiratory therapists, mastery of the larynx’s anatomy and function is essential for safe and effective airway management.
Whether in the ICU, operating room, or outpatient clinic, the larynx is at the center of many respiratory interventions. Understanding this structure enables respiratory professionals to assess, treat, and advocate for patients with airway and breathing difficulties with greater confidence and competence.
Written by:
John Landry is a registered respiratory therapist from Memphis, TN, and has a bachelor's degree in kinesiology. He enjoys using evidence-based research to help others breathe easier and live a healthier life.
References
- Suárez-Quintanilla J, Fernández Cabrera A, Sharma S. Anatomy, Head and Neck: Larynx. [Updated 2023 Sep 4]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025.