Corniculate cartilages

The corniculate cartilages are small, paired, cone-shaped cartilages located in the larynx. These cartilages are made of elastic cartilage and serve as part of the framework that supports the laryngeal tissues. They sit on top of the arytenoid cartilages and are involved in maintaining the structural integrity of the laryngeal inlet.

Location

The corniculate cartilages are situated at the apex of the arytenoid cartilages, which are found in the posterior aspect of the larynx. They are positioned within the aryepiglottic folds, just above the vocal cords. The corniculate cartilages are located near the back of the throat, close to the laryngeal inlet, where they assist in supporting the opening of the larynx.

Structure and Anatomy

The corniculate cartilages are small, conical structures that contribute to the overall framework of the larynx. While they are small in size, they play an essential role in providing structural support to the laryngeal tissues, particularly the aryepiglottic folds. Below is a detailed description of their anatomy.

Shape and Structure

• The corniculate cartilages are small, cone-shaped structures composed of elastic cartilage. Their pointed shape gives them a distinctive appearance, often likened to small horns or cones, which is why they are also referred to as the “horn cartilages.”
• Their elastic cartilage composition provides them with flexibility and resilience, allowing them to maintain structural integrity while moving with the other cartilages of the larynx during breathing and phonation.

Location in the Larynx

• The corniculate cartilages are located at the apex of the arytenoid cartilages, situated at the back (posterior aspect) of the larynx. They sit on top of the arytenoid cartilages, which are positioned on the superior border of the cricoid cartilage, and they contribute to the structure of the laryngeal inlet.
• The corniculate cartilages are embedded within the aryepiglottic folds, which are the soft tissue folds extending from the sides of the epiglottis to the arytenoid cartilages. Their location within the aryepiglottic folds helps them participate in maintaining the shape and support of the laryngeal opening.

Attachments and Relations

• Arytenoid Cartilages: The corniculate cartilages are directly attached to the arytenoid cartilages. The arytenoid cartilages are pyramid-shaped structures located at the back of the larynx that play a key role in vocal cord movement and sound production. The corniculate cartilages cap the top of the arytenoids, sitting at their apex.
• Aryepiglottic Folds: The corniculate cartilages are located within the aryepiglottic folds, which extend from the epiglottis to the arytenoid cartilages. These folds form the sides of the laryngeal inlet, and the corniculate cartilages help reinforce the folds, maintaining their structure.

Composition

• Like other smaller laryngeal cartilages, the corniculate cartilages are composed of elastic cartilage. Elastic cartilage is highly flexible, allowing the corniculate cartilages to adapt to the movement of the arytenoids and other structures within the larynx.
• Elastic cartilage contains a dense network of elastic fibers that give the corniculate cartilages the ability to bend and return to their original shape without damage. This flexibility is essential for their function within the dynamic environment of the larynx.

Associated Cartilages and Structures

The corniculate cartilages are part of a complex network of cartilages within the larynx, and they are closely associated with several key structures:

• Arytenoid Cartilages: As mentioned, the corniculate cartilages sit atop the arytenoid cartilages, which are pyramid-shaped and provide attachment points for the vocal cords. The movement of the arytenoid cartilages affects the position of the corniculate cartilages.
• Cuneiform Cartilages: The cuneiform cartilages are another set of small paired cartilages located slightly above and anterior to the corniculate cartilages. Both the corniculate and cuneiform cartilages provide support to the aryepiglottic folds.
• Cricoid Cartilage: The arytenoid cartilages, which the corniculate cartilages cap, are positioned on the superior border of the cricoid cartilage. The cricoid cartilage forms the base of the larynx and plays an important role in supporting the laryngeal structure.

Muscles Associated with the Corniculate Cartilages

Although the corniculate cartilages themselves do not have direct muscular attachments, they are influenced by the movement of muscles that control the arytenoid cartilages, to which they are attached.

• Intrinsic Laryngeal Muscles: The intrinsic muscles of the larynx, such as the posterior cricoarytenoid, lateral cricoarytenoid, and thyroarytenoid muscles, control the movement of the arytenoid cartilages. As these muscles act on the arytenoids, they also affect the position and movement of the corniculate cartilages.
• Aryepiglottic Muscle: This muscle, part of the aryepiglottic folds, helps pull the epiglottis down over the laryngeal inlet during swallowing. The corniculate cartilages are embedded in these folds, contributing to the function of the aryepiglottic muscle by providing structural support.

Blood Supply

The blood supply to the corniculate cartilages is shared with other laryngeal structures. It primarily comes from branches of the superior laryngeal artery and the inferior laryngeal artery.

• Superior Laryngeal Artery: A branch of the superior thyroid artery, this artery supplies the upper portion of the larynx, including the corniculate cartilages and associated structures.
• Inferior Laryngeal Artery: A branch of the inferior thyroid artery, this artery supplies the lower larynx, including portions of the arytenoid cartilages and surrounding tissues.

Innervation

The corniculate cartilages and the structures they are associated with are innervated by branches of the vagus nerve (cranial nerve X), which provides both sensory and motor control to the larynx.

• Recurrent Laryngeal Nerve: This nerve supplies most of the intrinsic muscles of the larynx, including those that control the arytenoid cartilages, which in turn affect the corniculate cartilages.
• Superior Laryngeal Nerve: The internal branch of the superior laryngeal nerve provides sensory innervation to the mucosal surfaces of the larynx, including the area surrounding the corniculate cartilages.

Lymphatic Drainage

The lymphatic drainage of the corniculate cartilages follows the pattern of other laryngeal structures, draining into the deep cervical lymph nodes.

Deep Cervical Lymph Nodes: Lymph from the laryngeal structures, including the corniculate cartilages, drains into these nodes, which are responsible for filtering lymph and preventing infections from spreading from the larynx.

Function

The corniculate cartilages play a vital role in supporting the laryngeal framework and facilitating proper functioning of the larynx. While small in size, their structural and functional contributions to the larynx are significant, especially in terms of airway protection, phonation, and swallowing. Below is a detailed explanation of their functions.

Support of the Aryepiglottic Folds

The corniculate cartilages are embedded within the aryepiglottic folds, which stretch from the arytenoid cartilages to the epiglottis. Their primary function is to provide structural support to these folds.

• Maintaining Shape and Rigidity: The corniculate cartilages help maintain the shape and stiffness of the aryepiglottic folds, preventing them from collapsing. This rigidity is essential during swallowing and phonation, as it ensures that the airway remains open and functional.
• Assisting in Swallowing: By supporting the aryepiglottic folds, the corniculate cartilages indirectly assist in swallowing. The aryepiglottic folds act as barriers, helping to close the laryngeal inlet during swallowing to prevent food and liquids from entering the trachea. The corniculate cartilages contribute to the structural integrity of these folds, ensuring proper airway closure during swallowing.

Facilitation of Phonation (Voice Production)

The corniculate cartilages, positioned atop the arytenoid cartilages, play a secondary role in phonation by influencing the movement of the arytenoid cartilages, which are directly involved in vocal cord control.

• Influencing Arytenoid Movement: The corniculate cartilages move in conjunction with the arytenoid cartilages during phonation. As the arytenoids rotate, tilt, or glide to adjust the tension and position of the vocal cords, the corniculate cartilages follow these movements. This coordinated action helps regulate vocal cord tension and position, which is critical for producing sound.
• Supporting Vocal Cord Function: The corniculate cartilages provide additional support to the arytenoids, ensuring that the vocal cords can effectively open, close, and adjust their tension during sound production. Proper movement of the arytenoids, influenced by the corniculate cartilages, ensures that the vocal cords vibrate at the right frequency to produce various pitches and tones.

Contribution to Airway Protection

The corniculate cartilages are involved in protecting the airway, particularly during swallowing, by supporting the aryepiglottic folds and assisting with laryngeal closure.

• Preventing Aspiration: During swallowing, the larynx elevates, and the epiglottis folds down to cover the laryngeal inlet. The aryepiglottic folds, supported by the corniculate cartilages, contribute to the sealing of the airway. By ensuring the proper functioning of the aryepiglottic folds, the corniculate cartilages help prevent food and liquids from entering the airway, reducing the risk of aspiration.
• Maintaining Airway Patency: The corniculate cartilages help keep the airway open during breathing by maintaining the structure of the aryepiglottic folds. This prevents the collapse of the folds into the airway, ensuring that airflow is not obstructed during normal respiration.

Enhancing Laryngeal Stability

Although small, the corniculate cartilages contribute to the overall stability of the larynx.

• Anchoring Arytenoid Movements: The corniculate cartilages sit atop the arytenoids and follow their movements. This relationship helps anchor and stabilize the arytenoids, providing support during the dynamic movements involved in breathing, speaking, and swallowing. This additional stability ensures that the arytenoid cartilages can move smoothly and efficiently.
• Contributing to Laryngeal Framework: The corniculate cartilages, together with the arytenoid and cuneiform cartilages, form a part of the laryngeal framework that supports the upper airway. This framework is essential for maintaining the open structure of the larynx during normal functions, ensuring that the airway remains unobstructed.

Supporting the Epiglottis in Airway Closure

The corniculate cartilages indirectly assist the epiglottis in closing off the airway during swallowing, helping to prevent food and liquids from entering the lungs.

• Interaction with the Epiglottis: The corniculate cartilages are part of the aryepiglottic folds, which connect the epiglottis to the arytenoid cartilages. When the epiglottis folds down to cover the laryngeal inlet during swallowing, the aryepiglottic folds, supported by the corniculate cartilages, help form a barrier that prevents materials from entering the trachea. This coordination ensures effective airway closure during the swallowing process.
• Facilitating Epiglottic Function: The corniculate cartilages provide structural integrity to the aryepiglottic folds, which, in turn, helps the epiglottis function properly. This is essential for maintaining a secure airway closure during swallowing, reducing the risk of choking or aspiration.

Coordination with the Arytenoid Cartilages

The corniculate cartilages are closely linked to the arytenoid cartilages, and their movements are coordinated with the actions of these larger cartilages.

• Extension of Arytenoid Function: Since the corniculate cartilages are positioned at the apex of the arytenoids, their movement is essentially an extension of the arytenoid cartilages’ actions. This coordination allows for smooth transitions between different laryngeal functions, such as speaking, breathing, and swallowing.
• Fine Control of Laryngeal Functions: The corniculate cartilages, in their relationship with the arytenoids, provide fine control over the movements that adjust the vocal cords. This precision is vital for modulating airflow through the vocal cords during breathing, phonation, and protection of the airway during swallowing.

Clinical Significance

The corniculate cartilages play a crucial role in maintaining the structural integrity of the larynx, particularly in supporting the aryepiglottic folds and assisting in vocal cord function. While small, they contribute to the movement and stability of the arytenoid cartilages, which are essential for vocalization and airway protection.

Clinically, issues affecting the corniculate cartilages, such as inflammation or trauma, can impair vocal cord movement, leading to difficulties in phonation or breathing. In conditions like laryngomalacia, where the soft tissues of the larynx collapse, the corniculate cartilages may lose their supportive function, contributing to airway obstruction, especially in infants. These cartilages may also be involved in conditions affecting the laryngeal framework, such as cancer, trauma, or infections, which can affect the stability and movement of the larynx.