Histology of the vocal cords

Histology of the Vocal Cords

The vocal cords, also known as vocal folds, are essential structures within the larynx that are involved in the production of sound. The histology of the vocal cords reveals a complex structure that is crucial for their function in phonation.

Structure

The vocal cords are composed of multiple layers, each with distinct histological characteristics:

Epithelium

The outermost layer of the vocal cords is the epithelium. This layer is typically a stratified squamous epithelium, which provides a protective barrier against mechanical stress during phonation.

Lamina Propria

Beneath the epithelium lies the lamina propria, which is divided into three sub-layers:

• **Superficial Layer**: Also known as Reinke's space, this layer contains loose connective tissue and is crucial for the vibratory properties of the vocal cords.
• **Intermediate Layer**: This layer is composed of elastic fibers that provide elasticity and strength.
• **Deep Layer**: The deep layer contains collagen fibers, which contribute to the tensile strength of the vocal cords.

Vocalis Muscle

The innermost layer is the vocalis muscle, a part of the thyroarytenoid muscle. This muscle is responsible for adjusting the tension of the vocal cords, thereby modulating pitch and tone.

Function

The histological structure of the vocal cords allows them to vibrate efficiently and produce sound. The epithelium and lamina propria work together to create a pliable yet resilient surface, while the vocalis muscle adjusts the tension and length of the vocal cords.

Pathology

Various conditions can affect the histology of the vocal cords, leading to voice disorders. Common pathological changes include:

• **Nodules**: Benign growths that can develop due to chronic vocal strain.
• **Polyps**: Fluid-filled lesions that can arise from acute vocal trauma.
• **Reinke's Edema**: Swelling of the superficial layer of the lamina propria, often associated with smoking and vocal abuse.

Clinical Relevance

Understanding the histology of the vocal cords is essential for diagnosing and treating voice disorders. Techniques such as laryngoscopy and biopsy are often used to examine the vocal cords' histological structure in clinical settings.

See Also

• Larynx
• Phonation
• Voice disorder
• Laryngoscopy