The Larynx: Understanding the Epiglottis, Vocal Cords, and Glottis

The larynx, commonly known as the voice box, plays a crucial role in speech production and protecting the airway during swallowing. Within the larynx, several structures work together, including the epiglottis, vocal cords, and glottis. Understanding these components is essential for comprehending their functions and the intricate processes involved in vocalization and airway protection.

The pathway of air from the nose to the larynx.
The pathway of air from the nose to the larynx.

The Epiglottis:


The epiglottis is a flap-like structure located at the base of the tongue, in the throat region. It is composed of elastic cartilage and is one of the nine cartilages that make up the larynx (voice box). The epiglottis plays a vital role in protecting the airway during swallowing.

Functions of Epiglottis:

The primary function of the epiglottis is to prevent food and liquids from entering the airway (trachea) and the lungs. During swallowing, the epiglottis folds backward to cover the opening of the larynx, known as the glottis. This closure prevents the entry of food, liquid, or saliva into the airway, directing them toward the esophagus instead. By sealing off the larynx, the epiglottis helps to prevent choking and aspiration pneumonia.

Structure and Location:

The epiglottis is a flexible, leaf-shaped cartilage that projects upwards from the base of the tongue and extends into the throat. It is attached to the hyoid bone, which supports the tongue, by a fibrous band called the hyoepiglottic ligament. The epiglottis is covered by mucous membrane, which gives it a smooth and moist surface.

The epiglottis is made up of a central stalk or stem called the petiolus, which divides into two broader sections. The broader superior portion is called the lamina, while the narrower inferior part is referred to as the tubercle.

During swallowing, the epiglottis receives signals from the swallowing reflex, triggering its folding backward to protect the airway. The epiglottis returns to its upright position after swallowing, allowing normal airflow during breathing and speech production.

Disorders and Conditions in Epiglottis:

While the epiglottis generally functions properly, there are certain disorders and conditions that can affect its normal operation:

  1. Epiglottitis: Epiglottitis is a serious condition characterized by inflammation and swelling of the epiglottis. It is usually caused by a bacterial infection, and it can lead to rapid onset of severe breathing difficulties. Epiglottitis requires immediate medical attention and treatment with antibiotics to prevent airway obstruction.
  2. Dysphagia: Dysphagia refers to difficulty in swallowing. When the epiglottis does not function properly or there are issues with the coordination of swallowing, food or liquids can enter the airway, causing choking or aspiration.
  3. Epiglottic Cysts or Tumors: Rarely, cysts or tumors can develop on the epiglottis, causing discomfort, swallowing difficulties, or changes in voice quality. These conditions may require medical intervention, such as surgical removal, depending on their size and impact on airway function.

The epiglottis is a crucial anatomical structure that safeguards the airway during swallowing. By closing off the entrance to the larynx, it prevents the entry of food and liquids into the trachea and lungs, thus protecting against aspiration. Understanding the role of the epiglottis helps in appreciating its significance in maintaining proper airway function and preventing respiratory complications.

The Vocal Cords:

vocal cords
vocal cords

The vocal cords, also known as vocal folds, are a pair of elastic tissues located within the larynx (voice box). They play a crucial role in speech production by vibrating and creating sound when air passes through them. The vocal cords are key components of the phonatory system, enabling us to produce a wide range of vocal sounds and communicate through speech and singing.

Structure and Location of Vocal Cords::

The vocal cords are located within the larynx, which is situated in the upper part of the neck, just below the base of the tongue. They are composed of a layered structure of muscle, ligament, and mucous membrane. Each vocal cord stretches horizontally across the larynx, from front to back, and is attached to the thyroid cartilage (Adam’s apple) in the front and the arytenoid cartilages in the back.

The vocal cords have a unique construction that allows them to vibrate and produce sound. They consist of a muscle known as the vocalis muscle, covered by layers of epithelial tissue. The upper layer is thin and pliable, while the lower layer is thicker and more elastic.

Function of Vocal Cords:

The primary function of the vocal cords is to generate sound through vibration. During speech and singing, air from the lungs passes through the larynx and causes the vocal cords to come together and vibrate. These vibrations produce sound waves that are shaped into speech sounds by the movements of the tongue, lips, and other articulatory structures.

When the vocal cords are relaxed and open, air can flow freely through the larynx during breathing. This is necessary for normal respiration. However, during vocalization, the vocal cords can adjust their position and tension to create different pitches and voice qualities.

When higher pitches are desired, the vocal cords are stretched, resulting in increased tension. This leads to faster vibrations and higher-frequency sounds. Conversely, lower pitches are produced when the vocal cords are relaxed, allowing for slower vibrations and lower-frequency sounds.

Disorders and Conditions in Vocal Cords:

Several disorders and conditions can affect the functioning of the vocal cords, leading to voice-related difficulties. Some common issues include:

  1. Vocal Cord Nodules and Polyps: These are benign growths that can develop on the vocal cords due to vocal strain or misuse. They can cause hoarseness, voice fatigue, and changes in voice quality.
  2. Vocal Cord Paralysis: Paralysis or weakness of the muscles that control the vocal cords can result in voice problems, breathiness, and difficulty speaking or singing.
  3. Vocal Cord Dysfunction: This condition involves abnormal vocal cord movements during breathing, which can cause breathing difficulties, wheezing, and stridor (noisy breathing).
  4. Laryngitis: Laryngitis refers to inflammation of the vocal cords, often due to infections, overuse, or irritants. It can cause hoarseness, a raspy voice, and discomfort in the throat.

Treatment for vocal cord disorders may involve voice therapy, vocal rest, surgical intervention, or medication, depending on the underlying cause and severity of the condition.

The vocal cords are crucial structures involved in voice production. By vibrating and modulating airflow passing through the larynx, they generate speech sounds and allow for effective communication. Understanding the structure and function of the vocal cords helps us appreciate the complexity of human speech and the importance of maintaining vocal health.

The Glottis:

The glottis is a crucial part of the larynx (voice box) and serves as the opening between the vocal cords. It plays a significant role in regulating airflow during breathing and sound production. Understanding the glottis is important for comprehending the mechanics of vocalization and the control of airflow through the larynx.

Structure and Location of the Glottis:

The glottis is the space between the vocal cords within the larynx. It is positioned at the upper part of the trachea (windpipe) and is surrounded by various cartilages, muscles, and connective tissues. The primary cartilages involved in shaping the glottis are the thyroid cartilage (housing the Adam’s apple), the cricoid cartilage, and the arytenoid cartilages.

Function of the Glottis:

The glottis has two main functions: regulating airflow during breathing and controlling sound production.

  1. Airflow Regulation: During normal breathing, the glottis remains open, allowing air to pass freely between the lungs and the environment. This open position ensures efficient airflow and gas exchange. The vocal cords are relaxed and apart, creating a wide glottic opening to minimize airway resistance.
  2. Sound Production: When producing vocal sounds, the glottis plays a critical role in controlling airflow and vocal cord vibration. To generate sound, the vocal cords come together and create a narrowed or partially closed glottic opening. As air from the lungs passes through the narrowed glottis, it causes the vocal cords to vibrate, producing sound waves. The pitch and intensity of the sound are influenced by the degree of glottic closure and the tension of the vocal cords.

By adjusting the tension, position, and shape of the vocal cords and glottis, a wide range of vocal sounds can be produced, enabling speech, singing, and other forms of vocal expression.

Disorders and Conditions of the Glottis:

Several disorders and conditions can affect the glottis and its proper functioning. These may include:

  1. Glottic Stenosis: Glottic stenosis refers to the narrowing or constriction of the glottic opening. It can be caused by scarring, injury, inflammation, or abnormal growths. Glottic stenosis can lead to breathing difficulties and voice changes.
  2. Vocal Cord Dysfunction: Vocal cord dysfunction (VCD) is a condition characterized by abnormal or paradoxical movements of the vocal cords during breathing. It can cause episodes of wheezing, shortness of breath, and difficulty in breathing.
  3. Laryngospasm: Laryngospasm is the sudden involuntary contraction of the muscles around the vocal cords, leading to a temporary closure of the glottis. It can result in a choking sensation, difficulty breathing, and voice disruption.

Treatment for glottic disorders depends on the specific condition and its underlying cause. It may involve medication, voice therapy, surgical interventions, or other therapeutic approaches to address the specific issue affecting the glottis.


The larynx, with its components such as the epiglottis, vocal cords, and glottis, plays a crucial role in speech production, swallowing, and airway protection. Understanding these structures and their functions helps us appreciate the complexity of human communication and the delicate balance required for efficient vocalization and swallowing. Recognizing and addressing disorders related to these structures are essential for maintaining optimal vocal health and overall well-being.

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