The Musculus vocalis is a special muscle, which in the vast majority of cases is counted among the internal muscles of the larynx. In this context, the muscle belongs to the so-called thyroarytaenoideus muscle, which is composed of the external pars externus and the internal vocalis muscle.
What is the vocalis muscle?
The vocalis muscle is also referred to by the synonymous name internus by some medical professionals. In English, the muscle is known as the vocal muscle. The muscle is part of the internal muscles of the larynx. In principle, the muscles of the larynx belong to the skeletal muscles. The muscles of the larynx are located in the midst of various cartilaginous tissues in the area of the larynx. Depending on how the muscles of the larynx are moved, a certain effect develops on the glottis as well as the vocal cords. In this way, phonation results through the larynx. Since the muscles of the larynx contribute significantly to vocalization, they are also called ‘phonation muscles’ in some cases.
Anatomy and structure
The vocalis muscle is characterized by its typical structure as well as its localization in the area of the internal musculature of the larynx. In addition, the vocalis muscle is characterized by its characteristic course. In principle, the vocalis muscle originates from the posterior region of the thyroid cartilage. This is the so-called thyroid cartilage, which is a cartilaginous element in the area of the larynx. In its further course, the vocalis muscle continues at the anterior region of the process at the stellate cartilage. The stellate cartilage is called Cartilagines arytaenoideae by medical terminology and is composed of two elements. These are part of the cartilaginous structure of the larynx and act as supports for the vocal organ. In addition, the vocalis muscle is intertwined with the fibers of some muscles, and these connections are primarily fibrous. The innervation of the vocalis muscle is also relevant in the context of its anatomy. The vocalis muscle is predominantly innervated by the so-called laryngeal nerve. This is the outermost branch of the laryngeal recurrent nerve. Its most important task is to innervate the entire musculature of the larynx. Only the cricothyroid muscle is not its responsibility.
Function and tasks
The vocalis muscle performs a variety of significant tasks and functions in the internal musculature of the larynx. Thus, the vocalis muscle contributes significantly to the function of the vocal organ. Basically, the vocalis muscle belongs to the so-called sphincter system at the larynx. In this context, the muscle is primarily responsible for closing the upper airways during the process of swallowing. This is achieved primarily by the vocalis muscle contracting during swallowing. Its second essential function is to assist in the production of voice. In particular, the vocalis muscle is responsible for ensuring tension in the vocal fold or vocal fold. The vocal folds are referred to in medical parlance as the labia vocalia or plica vocalis. They are two tissue-like folds characterized by a horizontal course. On the surface of the vocal folds there is a special type of mucous membrane. Basically, the vocal folds are located inside the larynx. The vocal folds make a significant contribution to phonation or voice production. The interwoven structures allow the finest gradations in tone. This results in an enormous effect on the vocal cords and their ability to vibrate. In principle, the vocal cords are ligaments of high flexibility and elasticity. The vocal cords unfold from the stellate cartilage to the thyroid cartilage. An important task of the vocalis muscle is its isometric contraction. In this way, it sets the oscillating mass in motion, which plays an essential role, especially when the voice volume changes. Isometric contraction of muscles, as in the case of the vocalis muscle, occurs when the length of the muscles in question remains the same. In addition, the vocalis muscle is a direct counterpart of the so-called cricothyroid muscle, which expands the vocal folds. This muscle is part of the external musculature of the laryngeal region.The antagonism between the two muscles becomes more significant as the volume of the voice and the depth of the sound increase. In addition, the vocalis muscle is also responsible for completely closing the so-called glottis. The glottis is referred to in medical terminology as the rima glottidis and represents a kind of gap between the two vocal folds. The vocalis muscle completely closes the area between the membranes, which also supports the vocal folds.
Diseases
Potential ailments and diseases associated with the vocalis muscle primarily relate to its two essential functions. The vocalis muscle performs essential tasks in the internal musculature of the larynx. Here it plays an important role especially in the process of swallowing as well as in phonation. Impairments of the vocalis muscle may lead to problems with the larynx during swallowing. In addition, difficulties in voice production or phonation are also possible if the vocalis muscle does not perform its function as usual.
