The thyroarytaenoid muscle is one of the skeletal muscles in humans. It is assigned to the laryngeal musculature. Through it, the closure of the glottis occurs.
What is the thyroarytaenoid muscle?
The larynx has an important function in the formation of speech. This process is called phonation. For it to occur, several components are coordinated within the organism. The thyroarytaenoid muscle is a subsection in this complex. It ensures that the glottis narrows. It has a slit-like shape and is located between the vocal folds. The glottis must close so that sounds can be produced. When this happens, the vocal cords relax. All this can only take place because the larynx is surrounded by various cartilages. These are softer than bone and thus they can be moved when the individual laryngeal muscles contract. As soon as the thyroarytaenoid muscle contracts, cartilaginous structures move closer together.
Anatomy and structure
The larynx is supplied by several muscles. The muscle system of the larynx can be divided into the internal and external muscles. The thyroarytaenoid muscle is one of the internal laryngeal muscles. It is innervated by the laryngeal recurrent nerve. The larynx, which in medicine is called the larynx, can be divided into three tiers. Vertically below one another are the supraglottis, also known as the vestibule laryngis. In the middle is the glottis or cavitas laryngis intermedia. In the lower sector is the subglottis or cavitas infraglottica. Surrounding all levels is a cartilaginous framework. The cartilago cricoida, cartilago thyroidea, cartilago epiglottica, and cartilagines arytaenideae completely encase the larynx. In the inner surface of the cartilago thyroidea is the origin of the thyroarytaenoid muscle. Opposite to it is the vocalis muscle. The path of the thyroarytaenoideus muscle begins at the upper edge of the arcus of the cartilago cricoidea. It runs obliquely to the processus muscularis of the cartilago arytaenoidea. The cartilago cricoida is called the cricoid cartilage. The cartilago arytaenideae is the stellate cartilage.
Function and tasks
Voice formation takes place in the larynx. This is surrounded by various cartilages and is activated by several muscles. Among them is the thyroarytaenoideus muscle. It supports the lateral cricoarytaenoideus muscle in its activity of ensuring the closure of the glottis. This is necessary to allow the vocal cords to move freely and produce sounds. The larynx has a vertical shape and is enclosed by several cartilages. They are called the cartilaginous framework. In descending order, they are the thyroid cartilage, the cricoid cartilage, the stellate cartilage, and the epiglottal cartilage. Phonotation originates in the area of the stellate cartilage, which is called the cartilago arytaenoidea. The cricoarytaenoideus lateralis muscle perpetrates inward rotation of the stellate cartilage. In this process, it receives assistance from the thyroarytaenoideus muscle. Together, their contraction causes the cartilage to contract. The result is that the glottis closes. At the same time, this process creates the opportunity for the vocal folds to move closer together. This provides the basis for the formation of the voice. To ensure complete phonation, other factors are required. They include intensive training and interaction of several areas in the human body. In addition to the closure of the glottis and the freely vibrating vocal folds, a continuous flow of air, a free embouchure tube and hearing are required. The embouchure tube is located in the oral, nasal and pharyngeal cavities. Air must be able to flow freely through the lungs, bronchi and trachea to speak and sing. If all systems work together, voice formation occurs.
Diseases
Ailments as well as diseases associated with hoarseness cause complications of phonation. Medical professionals refer to hoarseness as dysponia. This is a voice disorder that causes a change in timbre. The cause of this is the vocal cords. These are no longer able to vibrate freely in hoarseness. The voice becomes rough, scratchy and at the same time softer. Hoarseness can be triggered by various diseases. Infections, allergies or inflammations are among them. A respiratory infection additionally narrows the trachea.This may be bronchitis or angina. Inflammation of the trachea or larynx triggers hoarseness as well as an irritating cough. An inflammation of the nerves in the area of the larynx causes dysfunction or failure of the thyroarytaenoid muscle. A laryngeal carcinoma causes hoarseness in the initial stage and later, depending on its place of origin, presses on individual cartilages of the larynx. As a result, these can no longer perform their functions. A comparable situation occurs when benign neoplasms develop. This is the case, for example, with edema or cysts. Overuse of the vocal cords or a tear of the ligaments also have an effect on phonation. At the same time, cartilage on the larynx can be injured by accidents or falls and have consequences on their functional activity. Smoking, inhalation of toxic gases or continuous dust also affects the activity of the larynx. If paralysis of the vocal cords or the inferior laryngeal nerve occurs, the thyroarytaenoid muscle can no longer perform its activity because it is no longer supplied. Incorrect intubations cause trauma to the larynx. This occurs during prolonged intubation or as a result of intensive or rescue care. Intubation can trigger damage to the larynx and the vessels, nerves, and cartilage present there due to external circumstances during an emergency.
