The vocal folds project onto the thyroid cartilage. Clinical anatomy of the larynx

Larynx occupies a midline position in the upper part of the anterior region of the neck just below the hyoid bone. The larynx is located at the level of the IV-VI cervical vertebrae.

Upper limit, or entrance to the larynx, aditus laryngis, limited in front epiglottis, epiglottis, on the sides there are arytenoid-epiglottic folds, plicae aryepiglotticae, and behind - the apices of the arytenoid cartilages, apex cartilaginis arytenoideae.

Cricoid cartilage of the larynx, cartilago cricoidea, forms the lower border, or base of the larynx, on which the thyroid and arytenoid cartilages are located.

Below is the cricoid cartilage of the larynx firmly connected to the trachea through the cricotracheal ligament, lig. cricotracheale. The shape of the cartilage is close to the shape of a ring with a diameter of about 2-3 cm. The narrower part of the ring, facing anteriorly, forms an arc, arcus, which is located at the level of the VI cervical vertebra and is easily palpated. Its posterior part, a quadrangular plate (lamina cartuaginis cricoideae), together with the arytenoid cartilages, forms the posterior wall of the larynx.

Between the cricoid and thyroid cartilages of the larynx the cricothyroid ligament is stretched, lig. cricothyroideum. Its lateral sections are covered by muscles of the same name, and the middle section of the ligament, free of muscles, has the shape of a cone. Previously, the cricothyroid ligament was called lig. conicum. This is where the name of the operation of opening the larynx comes from - conicotomy.

Thyroid cartilage of the larynx, cartilago thyroidea, is the largest cartilage of the larynx. It forms the anterolateral wall of the larynx. Cartilage consists of two plates, lam. thyroideae, which join in front almost at a right angle. The protruding part at the top, prominentia laryngea, is called the Adam's apple, or Adam's apple. The protrusion of the larynx protrudes strongly forward in men and is hardly noticeable in women and children. In the anterior part of the cartilage there is a superior thyroid notch, incisura thyroidea superior, which is well defined by palpation.

The thyroid cartilage is firmly connected to the hyoid bone by the thyrohyoid membrane, membrana thyrohyoidea, covered by the muscles of the same name. This membrane is attached to the upper edge of the hyoid bone from behind in such a way that there remains a gap between it and the bone, often occupied by the mucous bursa, bursa retrohyoidea. The bursa can be the site of formation of a median cyst of the neck, and when it suppurates, phlegmon of the neck.

Epiglottis of the larynx, epiglottiis, shaped like a dog's tongue or leaf; it is wide at the top, narrowed at the bottom in the form of a stalk or stalk attached to the inner surface of the upper edge of the thyroid cartilage. The epiglottis consists of elastic cartilage; it is softer than other laryngeal cartilages. Its anterior surface (fades lingualis) faces the tongue, and its posterior surface (fades laryngea) faces the cavity of the larynx.

The larynx (larynx) enters the initial part of the respiratory tract, the upper part of which opens into the pharynx, the lower part passes into the trachea.

The larynx is located under the hyoid bone, on the front surface of the neck. In thin men, the contours of the larynx are well defined. In adult men, the upper edge of the larynx is on the border of CIV and Cv, and the lower one corresponds to Cvi (Fig. 3.1). In newborns, young people and women, the larynx is located slightly higher, in old people - lower. The anterior surface of the larynx, covered by muscles, can be easily felt through the skin. In men, in the upper section, the protrusion of the thyroid cartilage is easily identified - the Adam's apple (prominentia laryngea, s.pomum Adami). In women and children, it is soft and palpation is often difficult to determine.

In the lower part in front, between the lower edge of the thyroid cartilage and the upper edge of the cricoid, you can easily palpate the area of ​​the conical ligament (lig. conicum, s.cricothyreoideum), which is dissected (conicotomy is performed) if it is necessary to urgently restore breathing in case of asphyxia.

Next to the inferolateral surfaces of the larynx lie the lateral lobes of the thyroid gland, posterior to which are the neurovascular bundles of the neck. The posterior surface of the larynx is the anterior surface of the lower part of the pharynx, and at the level of the lower posterior edge is the upper part of the esophagus.

During swallowing and vocal production, the external muscles of the larynx raise and lower the larynx. Such mobility is functionally necessary (raising the larynx to the root of the tongue at the moment of swallowing); it is possible due to the fact that the larynx is connected by muscles through the hyoid bone with the tongue and lower jaw at the top, with the sternum and collarbones at the bottom.

The skeleton, or skeleton, of the larynx is shaped like a truncated pyramid; it consists of cartilages (cartilagines laryngis) connected by ligaments (Fig. 3.2). Among the cartilages there are three unpaired: supraglottic (cartilage epiglottica), thyroid (cartilage thyreoidea), cricoid (cartilage cricoidea), and three paired, skull-shaped (cartilagines arytaenoideae), horn-shaped (cartilagines corniculatae, s.santorini), cl. new data (cartilagines cuneuformes,

A-sagittal section: 1- uvula of the soft palate; 2 - root of the tongue; 3 - padglottis; 4 - aryepiglottic fold; 5 - vestibule of the larynx; 6 - buropoi sesamoid cartilage; t - tubercle of corniculate cartilage; 8 - laryngeal ventricle; 9 - arytenoid muscles; 10 - subglottic space; 11 - signet of the cricoid cartilage; 12 - entrance to the trachea; 13 - trachea; 14 - esophagus; 15 - thyroid gland; 16 - tracheal cartilage; 17 - arch of the cricoid cartilage; 18 - cricoid (conical) ligament; 19 - plate of thyroid cartilage; 20 - vocal fold; 21 - vestibular fold; 22 - adipose tissue; 23 - median thyrohyoid ligament; 24 - hypoglottic ligament; 25 - body of the hyoid bone; 26 - geniohyoid muscle; 27 - thyroglossal recess (duct dimention), 28 - blind foramen.

B - entrance to the laryngeal cavity: 1 - median lingual-nidharyngeal fold; 2 - epiglottis; 3 - protrusion of the epiglottis; 4 - glottis; 5 - pyriform sinus; 6 - glottis (intercartilaginous part), 7 - posterior wall of the pharynx; 8 - interarytenoid notch; 9 - tubercle of sesamoid cartilage; 10 - tubercle of corniculate cartilage, 11 - vocal fold; 12 - vestibular fold; 13 - aryepiglottic fold; 14 - pharyngeal-epiglottic fold; 15 - lingual epiglottic fold; 16 - fossa of the epiglottis; 17 - root of the tongue.

S. Wrisbergi). The basis, the foundation of the skeleton of the larynx is the cricoid cartilage. The anterior, narrower part is called the arc (arcus), and the rear, expanded part is called the signet, or plate (lamina). On the lateral surfaces of the cricoid cartilage there are small rounded elevations with a smooth platform - articular surfaces, the place of articulation with the thyroid cartilage (facies articularis thyreoidea). The largest thyroid cartilage is located above the anterior and lateral semicircles of the cricoid cartilage. Between the arch of the cricoid cartilage and the thyroid cartilage there is a wide gap made by the conical ligament (lig. conicum).

A - front view: 1 - epiglottis; 2 - large horn of the hyoid bone; 3 - granular cartilage; 4 - superior horn of the thyroid cartilage; 5 - thyroid cartilage; 6 - arytenoid cartilage, 7, 16 - cricoarytenoid ligaments; 8 - posterior thyroid cricoid ligament; 9 - thyroid cricoid joint; 10, 14 - lateral cricoid ligaments; 11 - cartilage of the pachea; 12 - membranous wall of the trachea, 13 - plate of the thyroid cartilage; 15 - lower horn of the thyroid cartilage; 17 - muscular process of the arytenoid cartilage; 18 - vocal process of the arytenoid cartilage; 19 - thyroepiglottic ligament; 20 - corniculate cartilage; 21 - thyrohyoid ligament; 22 - thyrohyoid membrane.

Thyroid cartilage received this name not only because of its shape, but also due to the role it plays in protecting the internal part of the organ. The thyroid cartilage consists of two plates (laminae) of irregular quadrangular shape, fused together anteriorly along the midline and diverging posteriorly. In the area of ​​the upper edge of the cartilage

Rice. 3.2. Continuation.

: 23 - small horn of the hyoid bone; 24 - body of the hyoid bone; 25 - protrusion of the thyroid cartilage (Adam's apple); 26 - cricothyroid ligament; 27 - arch of the cricoid cartilage; 28 - cricotracheal ligament; 29 - annular ligaments; 30 - oblique line; 31 - superior thyroid tubercle

In the midline there is a notch (incisura thyreoidea). The posterior, lower and upper corners of the plates of the stichoid cartilage are drawn in the form of long narrow processes - horns (cornua). The lower horns are shorter; on their inner side there is an articular surface for connection with the cricoid cartilage in the area of ​​facies articularis thyreoidea. The upper horns are directed towards the hyoid bone. Along the outer surface of the plates of the thyroid cartilage in an oblique direction from back to front and from top to bottom there is an oblique line (linea obliqua), to which three muscles are attached: the sternothyroid (m.stemothyreoideus), the thyrohyoid (m.thyreohyoideus) and the lower muscle that compresses the pharynx (m. constrictor pharyngis interior, s.m.thyreopharyngeus), starting from the back of the oblique line with part of its fibers.

At the posterosuperior end of the oblique line there is a non-permanent thyroid opening (for. thyreoideum), through which the superior laryngeal artery (a. laryngea superior) passes. On the inner surface of the angle formed by the plates of the thyroid cartilage in front, there is an elevation to which the anterior ends of the vocal folds are attached.

The third unpaired cartilage is located above the glottis and is shaped like a flower petal. It has a “petal” and a “stem” (petiolus) - wide and narrow parts. With the help of a ligament, the “stem” of the epiglottis is attached to the inner surface of the angle of the thyroid cartilage immediately below its superior notch. The “petal” of the epiglottis stands freely above the level of the thyroid cartilage, located behind the root of the tongue; during a swallow, it covers the entrance to the larynx and directs the bolus of food into the pear-shaped pockets. The anterior, somewhat convex surface of the epiglottis, directed towards the root of the tongue, is called the lingual surface (facies lingualis), and the posterior, facing the entrance to the larynx, is called the laryngeal surface (facies laryngea).

The “petal” of the epiglottis comes in different shapes: more often it is unfolded, and it may be more or less tilted back. These circumstances are of great importance when studying the laryngoscopic picture. When the epiglottis is elongated, folded into a semi-tube and sharply thrown back, which is more common in children, indirect laryngoscopy is difficult. In such cases, the larynx can only be examined using a special instrument - a laryngoscope or directoscope; This method is called “direct laryngoscopy”. On the surface of the petiolus of the epiglottis above the vocal folds there is a tubercle, which in some individuals is significantly pronounced and simulates a tumor, which sometimes leads to diagnostic errors.

The cricoid cartilages are located symmetrically above the plate (signet) of the cricoid cartilage on the sides of the midline. Each of them has the shape of an irregular three-sided pyramid, the apex of which is directed upward, somewhat posteriorly and medially, and the base (basis) is located on the articular surface (facies articularis arytaenoidea) of the cricoid cartilage.

The anterior surface of the arytenoid cartilage limits the entrance to the larynx posteriorly and is triangular in shape. Of the corners of the base of the cartilage, the anterior internal one, which is the place of attachment of the vocal muscle and therefore called the “vocal process” (processus vocalis), and the external muscular process (procesus muscularis) - the place of fixation of the posterior and lateral cricoarytenoid muscles (mm.cricoarytenoidei posterior et lateralis) are well defined. .

The wedge-shaped (v risberg) cartilages are located in the thickness of the aryepiglottic fold (plica aguepiglottica). They are elongated, small, their shape and size vary. Horn-shaped (santorine) cartilages are small, conical in shape, located above the apex of the arytenoid cartilages, sometimes fused with them. S eamoid cartilages - different in shape, size and position, small, often lie between the apex of the arytenoid cartilage and the corniculate cartilage, between the arytenoid cartilages or in the anterior part of the vocal folds.

Regarding the histological structure of individual cartilages of the larynx, it should be noted that the epiglottis, wedge-shaped, corniculate cartilages and the vocal process of the arytenoid cartilages are formed from elastic cartilage, and all the rest are from hyaline cartilage; in old age they sometimes ossify. The laryngeal cartilage in women is thinner and smaller than in men.

Joints and ligaments of the larynx. The cartilages of the larynx are connected to each other by ligaments and joints, allowing them a certain mobility in relation to each other.

S u st a s. The lateral surfaces of the cricoid cartilage are connected to the thyroid cartilage using the paired cricothyroid joint (articulatio cricothyreoidea). Both joints function simultaneously; When muscles contract, the upper part of the thyroid cartilage tilts forward or backward, thereby changing the distance between the thyroid and arytenoid cartilages, while the tension of the vocal folds increases or decreases, and the pitch of the voice increases or decreases.

The arytenoid cartilages, with the help of the cricoid joint, are connected by their bases to the upper edge of the plate of the cricoid cartilage. The articular capsule is reinforced along the posterior surface by lig. cricoarytaenoideum posterius. In this joint, rotational movements of the arytenoid cartilage around the longitudinal (vertical) axis are possible, as well as sliding movements forward, backward, medially and laterally. When rotating in this joint, the vocal processes of the arytenoid cartilages move closer or further away; when sliding along the cricoid cartilage, they diverge or come closer together. Consequently, movements in this joint also cause a change in the position of the vocal folds in relation to the midline, which determines the width of the glottis.

S v i z k i. 1. The thyrohyoid medial and lateral (lig. hyothyreoideum media et lateralis) ligaments are parts of the thyrohyoid membrane that connects the upper edge of the thyroid cartilage with the body and large horns of the hyoid bone. In the outer part of this membrane there are openings for the superior laryngeal artery and vein, as well as the internal branch of the superior laryngeal nerve (a.laryngea superios, v.laryngea superior, r. internus n.laryngei superior). 2. The epiglottic-thyroid (lig. thyroepiglotticum) ligament attaches the epiglottis to the upper edge of the thyroid cartilage. 3. The hypoglottic (lig. hyoepiglotticum) ligament connects the anterior surface of the epiglottis with the body and large horns of the hyoid bone. 4. The cricotracheal (lig. cricotracheale) ligament connects the cricoid cartilage with the first ring of the trachea. 5. The median cricothyroideum (lig. cricothyroideum medium, s.conicum) triangular ligament is stretched between the upper edge of the cricoid cartilage arch and the middle part of the lower edge of the thyroid cartilage. The lateral edges of this ligament pass without a sharp border onto the inner surface of the cartilage of the larynx, participating in the formation of an elastic layer between them and the mucous membrane. 6. The aryepiglottic fold (plica aryepiglottica) is located between the edge of the epiglottis and the inner edge of the arytenoid cartilage. It is the lower part of the quadrangular membrane (membrana quadrangularis), which is located between the edge of the epiglottis and the inner edge of the arytenoid cartilage. 7. The lingual-epiglottic middle and lateral ligaments (lig. glossoepiglotticum medium et lateralis) go from the anterior surface of the epiglottis to the middle and lateral parts of the root of the tongue. Between them, depressions are formed - vallecules.

Muscles of the larynx. There are external and internal muscles of the larynx. The first include three paired muscles that fix the organ in a certain position, raise and lower it: sternohyoid (m.sternohyoideus); sternothyroid (m.sternothyroideus); thyrohyoid (m.thyrohyoideus). These muscles are located on the anterior and lateral surfaces of the larynx. Movements of the larynx are also carried out by other paired muscles, which are attached from above to the hyoid bone, namely: mylohyoid (m.omohyoideus), stylohyoid (m.stylohyoideus) and digastric (m.digasticus).

The internal muscles of the larynx, there are eight of them (Fig. 3.3), depending on the function they perform, can be divided into the following groups.

Rice. 3.3. Muscular apparatus of the larynx.

(side view): 1 - direct portion of the cricoid muscle. 2 - oblique portion of the cricoid muscle; b -

(side view): 1-thyroid epiglottis muscle; 2 - lateral cricoarytenoid muscle; 3 - posterior cricoarytenoid muscle, 4 - arytenthyroid muscle.

B: 1 - aryepiglottic muscle; 2 - ksk!e arytenoid muscles; 3 - cricoid muscles; 4 - posterior cricoarytenoid muscle; 5 - transverse arytenoid muscle.

The paired posterior cricoid muscle (m.cricoarytenoideus posterior, s.m.posticus) expands the lumen of the larynx during inhalation due to posterior displacement and inward rotation of the muscle processes of the arytenoid cartilages, while the vocal processes diverge and the vocal folds move away from each other. This is the only muscle that ensures the opening of the lumen of the larynx.

Three muscles narrow the lumen of the larynx and thereby provide vocal function. The strongest of them is the lateral cricoid (m.cricoarytenoideus lateralis) begins on the lateral surface of the cricoid cartilage and is attached to the muscular process of the arytenoid . When it contracts, the muscular processes of the arytenoid cartilages move anteriorly and inward, and the vocal folds close in the anterior two-thirds. The unpaired transverse arytenoid (m.arytenoideus transversus) muscle is located between the arytenoid cartilages.

When this muscle contracts, the arytenoid cartilages move closer together, closing the glottis in the posterior third.

The function of this muscle is enhanced by the paired oblique cranial muscle (m.arytenoideus obliquus). It begins on the posterior surface of the muscular process of one arytenoid cartilage, and is attached to the apex of the arytenoid cartilage on the other side. Both of these muscles are located crosswise.

Two muscles stretch the vocal folds. Thyroarytenoideus (m.thyroarytenoideus) consists of two parts. The outer part (m.thyroarytenoideus extenus) is flat, quadrangular in shape, located in the lateral parts of the larynx, covered on the outside by a plate of thyroid cartilage. It starts from the inner surfaces of the plates of the thyroid cartilage. The muscle bundles on each side, directed obliquely backwards and upwards, are attached to the lateral edge of the arytenoid cartilage. The function of this muscle is to move the arytenoid cartilage anteriorly and rotate it outward around the longitudinal axis. The second part is the paired thyroarytenoid internal vocal muscle (m.thyroarytenoideus internus, s.m.vocalis). It is the lower part of the previous muscle and, in the form of a triangular-prismatic plate, stands from the lateral surfaces into the lumen of the larynx. This muscle begins anteriorly from the inner surface of the plate of the thyroid cartilage in the area of ​​the angle within its lower third and is directed horizontally posteriorly to the vocal process of the arytenoid cartilage. When this muscle contracts, the vocal folds (“vocal cords” in the old nomenclature) thicken and shorten. The cricoid (m.cricothyroideus) muscle begins on the anterior surface of the cricoid cartilage on the side of the midline and ends on the lower edge of the thyroid cartilage and the lower horn of the thyroid cartilage. When this muscle contracts, the thyroid cartilage bends forward, thereby stretching the vocal folds and narrowing the glottis.

The lowering of the epiglottis and its posterior tilt are carried out by two muscles. The paired aryepiglotticus (m.aryepiglotticus) is located between the apex of the arytenoid cartilage and the edge of the epiglottis. From this muscle, covered with a mucous membrane, the aryepiglottic fold (lig. aryepiglotticus), part of the lateral part of the entrance to the larynx, is formed. The paired thyroepiglotticus muscle (m.thyroepiglotticus), in the form of an elongated, weakly expressed plate, is stretched between the inner surface of the angle of the thyroid cartilage and the lateral edge of the epiglottis.

Adjacent to the inner surface of the cartilage of the larynx is the elastic membrane of the larynx (membrana elastica laryngis). It is divided into a quadrangular membrane and an elastic cone. The quadrangular membrane makes up the upper part of the elastic membrane of the larynx and is adjacent to the inner surface of the plates of the thyroid cartilage. It is stretched from the lateral edges of the epiglottis and the inner surface of the angle of the thyroid cartilage to the inner surface of the arytenoid and corniculate cartilages. The lower edges of the quadrangular membranes on both sides, somewhat closer to each other in the lower section, form the folds of the vestibule (or false vocal cords). The elastic cone is the lower part of the elastic membrane of the larynx and is formed from elastic bundles that begin on the inner surface of the plates of the thyroid cartilage in the area of ​​the angle. From here, the bundles fan out in such a way that the anterior inferior ones go vertically downwards and, attaching to the upper edge of the arch of the ring, form the cricothyroid ligament (lig. conicum), and the posterior superior ones, having a sagittal direction, wedge into the lumen of the larynx, ending on the vocal processes of the arytenoid cartilages.

Laryngeal cavity. It is formed by cartilage, ligaments, muscles and elastic membrane. The inside of the larynx is lined with mucous membrane. There are three levels in the larynx: the upper, or vestibular, above the vocal folds, the middle - the region of the vocal folds, and the lower - the subvocal cavity.

Knowledge of the structure of the entrance to the larynx is of great clinical importance. To the side and posterior to the larynx there are pear-shaped recesses, bounded on the lateral side by the large horns of the hyoid bone, and in front by the sublingual-thyroid membrane and the plate of the thyroid cartilage. The outer lateral wall of the pyriform sinus is penetrated by the internal branch of the superior laryngeal nerve and the superior laryngeal artery, which at the bottom of the sinus form a fold of mucous membrane running posteriorly and downward.

The entrance to the larynx is limited in front by the epiglottis, behind by the tips of the arytenoid cartilages, and on the sides by the aryepiglottic folds. In the thickness of these folds lie thin muscles of the same name, and in the posterior section there are corniculate and wedge-shaped cartilages. These cartilages form two tubercles: wedge-shaped (tuberculum cuneiforme) and corniculate (tuberculum corniculatum). From the anterior surface of the epiglottis facing the root of the tongue, three lingual-epiglottic folds are directed to the root of the tongue: one median and two lateral (plicae glossoepigloticae mediana et lateralis) . The depressions between these folds are called pits (valleculae) of the epiglottis (valleculae glossoepiglotticae). In the cavity of the larynx, two pairs of horizontal folds of the mucous membrane are located symmetrically: the upper ones are called vestibular folds (plicae vestibularis), the lower ones are called vocal folds (plicae vocalis). They are formed by triquetral muscles, the posterior ends of which are attached to the vocal processes, and the anterior ends to the inner surface of the thyroid cartilage. That part of the laryngeal cavity, which is located above the vocal folds (see Fig. 3.1), has the appearance of a cone-shaped cavity, tapering downwards, which is called the vestibule of the larynx (vestibulum laryngis). The gap formed between the vocal folds is called the vocal fold (rima glottidis) - the middle floor of the larynx. Through this gap there is communication with the lower part of the laryngeal cavity (cavitas infraglottica) - the subglottic cavity. Vestibular and vocal folds are paired. On each side between the vestibular and vocal folds there are depressions - the laryngeal ventricles; outward and anteriorly, a pocket is defined in the ventricle, ascending upward. The length of the vocal folds in men is 20-22 mm, in women 18-20 mm, the width of the glottis in the back of adults ranges from 17 to 20 mm.

The mucous membrane of the larynx is a continuation of the mucous membrane of the hypopharynx, and below it passes into the mucous membrane of the trachea. It should be borne in mind that a loose submucosal layer is developed in the subglottic cavity; its inflammatory edema (more often in children) is called false croup (in contrast to true croup - fibrinous-membranous). The mucous membrane of the larynx is covered mainly by multirow columnar ciliated epithelium. In the area of ​​the vocal folds, interarytenoid space, lingual surface of the epiglottis, and aryepiglottic folds, the integumentary epithelium has the character of a multilayered squamous epithelium.

The submucosal layer of the larynx contains a large number of serous-mucosal glands, but they are unevenly distributed. The largest number of these glands are located in the area of ​​the laryngeal ventricles, vestibular folds and in the subglottic space. There are no glands in the vocal folds.

In the thickness of the mucous membrane of the larynx there are accumulations of lymphoid tissue of different sizes. It is most developed in the area of ​​the laryngeal ventricles and aryepiglottic folds.

Topography of the larynx. The larynx is suspended from the hyoid bone by the thyrohyoid membrane; downwards it passes into the trachea. In front, the larynx is covered with skin, subcutaneous fatty tissue and the superficial fascia of the neck. To the side of the midline on the thyroid and cricoid cartilages of the larynx lie the sternohyoid muscles (right and left), and below them are the sternothyroid and thyrohyoid muscles. Posteriorly, at the level of the lower edge of the cricoid cartilage, the larynx borders the laryngeal part of the pharynx and the entrance to the esophagus. The projection of the vocal folds corresponds to the lower third of the thyroid cartilage. To the lower edge of the cricoid cartilage anteriorly

1 - epiglottis; 2 - hyoid bone; 3 - vagus nerve; 4 - common jugular vein; 5 - facial vein; 6 - superior thyroid vein; 7 - common carotid artery; 8 - cricothyroid muscle; 9 - cricothyroid artery; 10- inferior thyroid vein; 11 - thyroid venous plexus, 12 - thyroid gland; 13 - arch of the cricothyroid cartilage; 14 - thyroid cricoid ligament; 15 - plate of thyroid cartilage; 16 - lateral thyrohyoid ligament; 17 - median stichohyoid ligament; 18 - superior thyroid artery; 19 - superior laryngeal artery; 20 - superior laryngeal nerve.

The fascia of the thyroid gland is attached, the lateral parts of which are covered by the sternohyoid and sternothyroid muscles. On the sides of the larynx there are neurovascular bundles (Fig. 3.4).

The blood supply to the larynx (see Fig. 3.4) is carried out by the upper and lower laryngeal arteries (aa.laryngea superior et inferior). The upper, largest, is a branch of the superior thyroid artery (a.thyroidea superior), which usually starts from the external carotid artery, less often from the bifurcation or even the common carotid artery; the lower one originates from the inferior thyroid artery (a.thyroidea inferior), which is a branch of the thyroid-cervical trunk (truncus thyrocervicalis). The superior laryngeal artery, together with the nerve of the same name, passes through the thyrohyoid membrane and divides inside the larynx into small branches. Another branch departs from it (or from the superior thyroid artery) - the middle laryngeal artery (a.laryngea media), which anastomoses with the artery of the same name on the opposite side in front of the conical ligament. The inferior laryngeal artery approaches the larynx along with the inferior laryngeal nerve. Venous drainage is carried out by a number of plexuses that are connected to the venous plexuses of the pharynx, tongue and neck. The main outflow of blood from the larynx goes through the superior thyroid vein into the internal jugular vein.

Lymphatic flow The lymphatic network is most developed in the area of ​​the mucous membrane of the ventricles and the upper floor of the larynx. From here and from the middle floor of the larynx, lymph collects in the deep cervical lymph nodes located along the internal jugular vein, especially at the level of the division of the common carotid artery, as well as at the posterior belly of the digastric muscle (m.digasticus). From the lower floor, lymph flows into the nodes located in front of the anterior thyroid ligament, along the internal jugular vein, and pretracheal.

Innervation of the larynx is carried out by the sensory and motor branches of the sympathetic and vagus nerves (Fig. 3.5).

1. The superior laryngeal nerve (n.laryngeus superior) departs from the vagus nerve in the neck and is divided into two branches: the external (r.externus) of a mixed nature and the internal (r.intemus), mainly sensitive.

2. The left lower laryngeal nerve (n.laryngeus inferior, s.recurrens) is separated from the vagus at the place where it goes around the aortic arch, and the right one departs from the vagus nerve at the level of the subclavian artery. After leaving the vagus nerve, the recurrent (lower laryngeal) nerve goes up and enters the larynx posterior to the junction of the lesser horn of the thyroid cartilage with the cricoid cartilage and supplies motor fibers to all the internal muscles of the larynx (excluding the anterior cricothyroid). The superior and inferior laryngeal nerves are mixed, but the superior is primarily sensory and the inferior is primarily motor. Both laryngeal nerves have connections with the sympathetic nerves.