The stellate cartilages (ary cartilages) are part of the larynx and have a significant influence on vocalization. They are connected by muscles, which makes them extremely mobile. Because of their external shape, they are sometimes called pouring basin cartilages.
What are the stellate cartilages?
The two stellate cartilages are located on the upper posterior articular surfaces of the cricoid cartilage. When the interpositional cartilage muscles that connect them tighten, the positional cartilages move closer together. These movements bring the vocal folds closer together, which are attached to the anterior part of the positional cartilages. In addition, the small glottis located between the vocal cords is widened or narrowed in this way. This is a crucial prerequisite for voice production (phonation). Another muscle running laterally to the cricoid cartilage is responsible for moving the vocal folds away from each other, which in turn is important for inhalation.
Anatomy and structure
In addition to the relatively small stellate cartilages, the human larynx consists of the much larger thyroid cartilage, the cricoid cartilage, and the epiglottis. The so-called horn cartilages are also located on the stellate cartilages. The thyroid cartilage is easily visible and palpable from the outside; it forms the anterior wall of the larynx. Colloquially, the thyroid cartilage is called the Adam’s apple. The cricoid cartilage lies horizontally below it, followed by the cartilaginous braces of the trachea. The epiglottis then closes the entrance to the larynx against the pharynx and is connected to the thyroid cartilage. In addition to the muscles, the various cartilages are held together by ligaments. The larynx itself is suspended from the hyoid bone by means of a membrane and is covered on the inside with a mucous membrane. The vocal cords (vocal folds) stretch between the two stellate cartilages and the posterior wall of the thyroid cartilage. The spacing and tension of the vocal folds and the work of the laryngeal muscles essentially provide the basic sound of the human voice. It is also called primary laryngeal sound (primary sound). It is then formed into speech sounds by movements of the tongue and mouth. Resonances in the throat, mouth and nose finally result in the voluminous sound of the voice.
Function and tasks
During the process of swallowing, the larynx is pulled forward and upward by its muscles, thus closing it with the epiglottis. This mechanism prevents solid or liquid food from entering the trachea. Inflammations of the larynx are relatively common. They often stem from respiratory tract infections. Laryngeal cancer, in turn, is a typical disease among smokers. Specific infectious diseases, such as diphtheria, preferentially appear as laryngitis. In many cases, the vocal cords are also severely affected. As soon as their finely tuned muscle system is damaged, their coarse tension is easily altered. The vocal folds can then no longer regulate the pitch of the voice properly, which is why, for example, the voice becomes hoarse and brittle (“robot phenomenon”). The male larynx is usually much larger than the female larynx. All cartilages of the larynx except for the epiglottis develop a strong tendency to ossification, which accelerates significantly with age. The laryngeal cartilages in particular are at high risk of cartilage dermatitis. It occurs rarely, but is very dangerous. Severe suppuration can subsequently affect the stellate cartilages, which in the worst case leads to rejection of the cartilages. In such cases, they are then expelled by coughing. Often the cartilages and with them the vocal cords are damaged by very diverse mucous membrane inflammations (laryngeal catarrh). Inhalation of cold, dusty and rough air is often enough for this. In addition, mucous membrane diseases are caused by very strained speaking or singing. They have the effect of increased mucus secretion and frequent coughing. When the mucous membranes swell noticeably, the voice often changes significantly. It suddenly swings from a rather low vocal range to an unusually high pitch. Temporary voicelessness due to chronic hoarseness is also possible.
Diseases
Ulcers in the laryngeal area usually form on the mucous membranes as well. For example, syphilis can cause very serious disfigurements of the larynx. These are called obscurations. They are often followed by scarring.The voice is often threatened with silencing because the glottis becomes very narrow or even closes completely. Very often, laryngitis occurs, in the course of which large tuberculous ulcers attack the mucous membrane. These threaten the larynx to such an extent that individual cartilages such as the two stellate cartilages can be triggered and secreted. In addition, the epiglottis can be destroyed and the vocal folds destroyed. Thus, the stellate cartilages can no longer fulfill their function. Anatomically, the posterior ends of the vocal folds are connected to the two pelvic cartilages. When breathing, the vocal folds open wide; the glottis between them thus acquires its typical triangular shape. If an opera singer has to produce a particularly high note, her vocal folds open and close about one thousand times per second. Many different muscles are involved in this extremely sensitive mechanism. The vocal folds have a layered structure. The vocal muscle forms the basis. Above it lie elastic fibers (lamina propria). These form a ligamentous support that extends from the thyroid cartilage to the two stellate cartilages. These are the vocal cords proper (ligamentum vocale). Like the ary cartilages themselves, they are covered on their surface with sensitive mucous membranes. A wide variety of pathogens settle there very quickly and easily, which can cause inflammation in the throat area and thus impair the voice.
