One of the anatomical formations of the upper respiratory tract is the larynx. It seems to the layman as a moving tube, which somewhere in its depth contains the vocal cords involved in the formation of the voice. Usually, knowledge ends there. In fact, things are a little more complicated. Therefore, it is worth telling more about this.
Topography
The larynx is located opposite IV, V and VI of the cervical vertebrae, starting immediately behind the hyoid bone and passing along the front surface of the neck. Behind her is a throat. It communicates with the larynx through the entrance to the larynx, but so that food does not enter the lungs and air into the stomach, nature has provided such an important detail as the epiglottis, which overlaps the lumen of the pharynx during inspiration and moves the larynx when swallowing, sharing thus the function of these organs.
Large neurovascular bundles of the neck are located on the sides of the larynx, and in front of all this is covered by muscles, fascia and thyroid gland. From below, it passes into the trachea, and then into the bronchi.
In addition to the muscle component, there is also cartilage, represented by nine half rings, providing reliability and mobility of the organ.
Features in men
A characteristic feature of the structure of the larynx in representatives of the stronger sex is the presence of an Adam's apple, or Adam's apple. This is part of the thyroid cartilage, which for some reason is more prominent in men than in women. Although it would be more logical to assume the opposite situation, because the muscular frame of the neck, which should cover the cartilage, is weaker in women.
Anatomy
The larynx is a cavity that is covered on the inside by a smooth and moist tissue - the mucous membrane. Conventionally, the entire organ cavity is divided into three departments: upper, middle and lower. The upper one is the vestibule of the larynx, they are narrowed downwards in the form of a funnel. Middle is the gap between false and true vocal folds. The lower part is used to communicate with the trachea. The most important and most complex department is the middle one. Cartilages and ligaments of the larynx are located here, thanks to which the voice is formed.
Voice education
The space between the vocal cords is called the "glottis". Contraction of the muscles of the larynx changes the tension of the ligaments, and the configuration of the gap changes. When a person exhales, air passes through the glottis, causing the ligaments to vibrate. This is what makes the sounds we pronounce, in particular vowels. In order to pronounce a consonant sound, the participation of the palate, tongue, teeth and lips is also necessary. Their coordinated work allows you to talk, sing and even imitate the sounds of the environment and imitate the voices of other people or animals. The coarser low voice in men is explained by the fact that their ligaments are longer anatomically, which means they vibrate with a greater amplitude.
Ontogenesis
Depending on the age of the person, the structure of the larynx can also change. This is partly why men break their voices after puberty. Newborns and infants have a short and wide larynx, it is located higher than that of an adult. There are no horns of cartilage and thyroid lingual ligaments. She will take the final form only by the age of thirteen.
Larynx wall
If viewed from a topographic point of view, then from the outside inward its layers are arranged as follows:
- Leather.
- Subcutaneous tissue.
- Cartilage, ligaments, muscles.
- Fibrous-elastic sheath (represented by connective tissue).
- The mucosa is a multinucleated ciliated epithelium and fibers of unformed connective tissue that fuse with the previous layer.
- The outer connecting plate is elastic, covering the cartilage of the larynx.
Rigid laryngeal framework
As mentioned above, there is a phylogenetically formed apparatus that supports the larynx. Cartilages of the larynx are dense half rings that hold the remaining tissues of this part of the neck and give the organ the appearance of a hollow tube. Between themselves they are connected by bundles. Distinguish single and paired cartilage of the larynx.
Single cartilage
In the anatomy of an organ, three cartilages are distinguished that do not have doubles. Unpaired cartilages of the larynx are located on one axis, one above the other.
- The epiglottis cartilage, or epiglottis, is a thin plate in shape resembling a leaf or petal of a flower. The wide part is located above the thyroid cartilage, and the narrow, also called the stalk, is attached to its inner corner.
- Thyroid - the largest cartilage of the larynx, located between the epiglottis and cricoid cartilage. Its name corresponds to both the form and function of this part of the organ. The thyroid cartilage of the larynx serves to protect its inner part from trauma. It is formed by two quadrangular plates fused in the middle. In this place, a ridge forms, on top of which there is an eminence, to which the vocal cords are attached. On the sides of the plate are paired processes - horns (upper and lower). Those that are below, articulate with the cricoid cartilage, and the upper ones with the hyoid bone. On the outside of the cartilage there is an oblique line to which the external muscles of the larynx are partially attached.
- The cricoid cartilage of the larynx is the basis of the skeleton of an organ. Its shape is fully consistent with the name: it looks like a men's ring, unfolded signet back. On the sides there are articular surfaces for connection with the arytenoid and thyroid cartilage. This is the second major laryngeal cartilage.
Paired cartilage
There are also three of them, since nature loves symmetry and seeks to show this love in any possible case:
- Sickle. The arytenoid cartilage of the larynx in shape resembles a trihedral pyramid, the apex of which is turned back and slightly towards the center of the body. Its base is part of the surface of the cricoid joint. Muscles are attached in the corners of the pyramid: in the front - the vocal, and in the back - the posterior and anterior cricoid muscles.
- Horn-shaped are located above the tips of arytenoid cartilage.
- Wedge-shaped are usually located in scooped-epiglottis folds. The last two pairs of cartilage are sesame-shaped and can vary in shape and location.
All these formations give shape to such an organ as the larynx. Cartilages of the larynx perform the functions necessary to maintain the normal functioning of a person. This is especially noticeable in relation to voice formation.
Joints
As already mentioned above, cartilage is interconnected through ligaments and joints. Two paired joints are distinguished in the larynx:
- Between the cricoid and thyroid cartilage. They are formed by the lateral surfaces of the cricoid cartilage, which are adjacent to the lower thyroid horn. When moving in this joint, the tension of the ligaments changes, and therefore the pitch of the voice.
- Between cricoid and arytenoid cartilages. It is formed by the articular surfaces (lower parts of the pyramid) of the arytenoid cartilage and the articular platform of the cricoid cartilage. Moving relative to each other, these anatomical formations change the width of the glottis.
Ligaments
Being a mobile organ, ligaments have a great influence on how the larynx is arranged. Cartilage of the larynx is maintained in dynamic equilibrium with the help of connective tissue cords:
- The thyroid-lingual ligament is part of the large shield-hyoid membrane, with which the entire larynx is attached to the hyoid bone. A neurovascular bundle feeding the organ passes through it.
- The thyroid nasopharyngeal ligament serves to connect the epiglottis to the thyroid cartilage.
- The hyoid-epiglottic ligament.
- The finger trachea ligament connects the larynx with the trachea, attached to the first cartilage of the larynx.
- The conical ligament combines the cricoid and thyroid cartilage. In fact, it is a continuation of the elastic membrane that runs along the inner surface of the larynx. It is the layer between the cartilage and the mucosa.
- The vocal fold is also part of the elastic cone covering the vocal muscle.
- Cherpalonadgortannaya ligament.
- Lingual-nasopharyngeal ligaments combine the root of the tongue and the anterior surface of the epiglottis.
Muscle
There are two classifications of the muscles of the larynx. The first is functional. She divides all muscles into:
- Constrictors that narrow the glottis and larynx, making it difficult for air to pass through.
- Dilators needed to expand the larynx and glottis, respectively.
- Muscles that can change the tension of the vocal cords.
According to the second classification, they are divided into external and internal. We will talk about them in more detail.
External muscles
The external muscles, as it were, wrap the larynx. Laryngeal cartilage is supported not only from the inside, but also from the outside. Conventionally, anatomists divide the outer group into two more: those that are attached to the thyroid cartilage, and those that attach to the bones of the facial skeleton, can be attributed to the first.
First group:
The second group:
- sternohyoid;
- scapular-hyoid;
- awl-sublingual;
- double-abdominal;
- chin-hyoid.
Internal muscles
They are necessary in order to change the position of the epiglottis and to help it fulfill its functions, as well as to change the configuration of the glottis. These muscles include:
- Sherpalonadgortannaya fold, which forms a scherpalonadgortannaya fold. During swallowing, the contraction of this muscle changes the position of the epiglottis so that it blocks the entrance to the larynx and does not allow food to pass there.
- The shield of the throat, on the contrary, with contraction pulls the epiglottis towards itself and opens the larynx.
- The lateral cricillary regulates the width of the glottis. When it contracts, the ligaments come closer together and the glottis becomes narrower.
- The posterior cricoid is contracted during inspiration, and the vocal folds diverge, stretching back and to the side, allowing air to pass further into the respiratory tract.
- The vocal muscle is responsible for the characteristics of the vocal cords, how long or short they are, stretched or relaxed, whether they are the same in relation to each other. The timbre of the voice, its aberration, and vocal abilities depend on the work of this muscle.
Laryngeal function
The first function, of course, is respiratory. And it consists in regulating the air flow passing through the departments of the respiratory tract. Changing the width of the glottis does not allow air to inhale excessively quickly into the trachea and bronchi. Conversely, air cannot leave the lungs too quickly until gas exchange has passed.
The ciliated epithelium of the laryngeal mucosa takes on its second function - protective. It manifests itself in the fact that small particles of dust and food do not enter the lower respiratory tract due to the coordinated work of the cilia. In addition, the nerve endings, which are present on the mucosa in many, are very sensitive to foreign bodies and provoke a coughing attack when irritated. At this moment, the epiglottis closes the entrance to the larynx, and nothing extraneous gets there. If the object still fell into the larynx, the cartilages of the larynx reflexively interact with each other, and the glottis overlaps. This, on the one hand, prevents the ingestion of food and other bodies into the bronchi, on the other hand, it blocks the access of air. If help does not arrive in time quickly, then the person dies.
Last on our list is the vocal function of the larynx. It is completely dependent on the anatomical structure of the larynx and on how much a person owns his voice apparatus. In the process of growth and development, people learn to speak, sing, recite poetry and prose, imitate the voices of animals or the sounds of the environment, and sometimes even parody other people. The higher the level of control of your body, the more opportunities a person has.
Such, in a nutshell, is the normal topographic anatomy and physiology of the larynx. From the article you learned about what important function it performs in the activity of the human body and that the cartilage of the larynx plays an important role here. Thanks to her, we breathe normally, speak and don’t choke every time we eat something. Unfortunately, she is more susceptible to infectious diseases and tumor processes than others.