Cricoarytenoid muscle

Cricoarytenoid Muscle

Diagram of the larynx showing the cricoarytenoid muscle.

The cricoarytenoid muscle is a key muscle in the human larynx that plays a crucial role in the movement of the vocal cords. It is involved in the opening and closing of the glottis, which is essential for phonation and breathing.

Anatomy

The cricoarytenoid muscle is divided into two distinct parts: the posterior cricoarytenoid muscle and the lateral cricoarytenoid muscle.

Posterior Cricoarytenoid Muscle

The posterior cricoarytenoid muscle is the only muscle responsible for abducting the vocal cords, which means it opens the glottis. It originates from the posterior surface of the cricoid cartilage and inserts into the muscular process of the arytenoid cartilage.

Lateral Cricoarytenoid Muscle

The lateral cricoarytenoid muscle adducts the vocal cords, closing the glottis. It originates from the lateral part of the cricoid cartilage and inserts into the muscular process of the arytenoid cartilage.

Function

The primary function of the cricoarytenoid muscle is to control the tension and position of the vocal cords. This is essential for producing sound and protecting the airway during swallowing. The posterior cricoarytenoid muscle opens the vocal cords, allowing air to pass through the larynx, while the lateral cricoarytenoid muscle closes the vocal cords, which is necessary for phonation.

Innervation

The cricoarytenoid muscle is innervated by the recurrent laryngeal nerve, a branch of the vagus nerve. This nerve provides motor innervation to all the intrinsic muscles of the larynx except for the cricothyroid muscle.

Clinical Significance

Dysfunction of the cricoarytenoid muscle can lead to voice disorders and breathing difficulties. Paralysis of the posterior cricoarytenoid muscle can result in an inability to abduct the vocal cords, leading to airway obstruction. Conversely, paralysis of the lateral cricoarytenoid muscle can cause a breathy voice due to incomplete closure of the vocal cords.

Related Pages

• Larynx
• Vocal cords
• Phonation
• Recurrent laryngeal nerve