Pharynx

Pharynx - an unpaired organ located in the region of the head and neck, is part of the digestive and respiratory systems. It is a hollow funnel-shaped tube suspended from the outer base of the skull. The upper part of the pharynx (vault of the pharynx) is attached to the pharyngeal nape of the occipital bone, the lateral parts to the pyramids of the temporal bones (in front of the outer carotid opening) and to the medial plate of the pterygoid process. At the bottom, the pharynx passes into the esophagus at the level of the sixth cervical vertebra. The length of the pharynx in an adult is 12-15 cm. Behind the pharynx are the pre-inferent muscles, the prevertebral plate of the cervical fascia, and the cervical spine. Between the posterior wall of the pharynx and the plate of the cervical fascia is the pharyngeal space (spatium retropharyngeum), filled with a loose fibrous connective tissue. Oropharyngeal lymph nodes are located in the pharynx.

To the side walls of the pharynx, the obschach and the internal carotid artery, the internal jugular vein, the vagus nerve, the large horn of the hyoid bone, the plate of the thyroid larynx of the larynx are adjacent to each side of the pharynx.

On the anterior wall of the pharynx, openings of the nasal cavity (choana) are opened into it, and below it there is an opening of the oral cavity - fauces. The entrance to the larynx is even lower. Allocate the nasal part of the pharynx (pars nasalis pharyngis), or the nasopharynx, located behind the khohan. Oral part of the pharynx (pars oralis pharyngis), or oropharynx, is at the level from the palatine curtain up to the entrance to the larynx. The throat part of the pharynx (pars laryngea pharyngis), or the larynx, is located between the entrance to the larynx at the top and the pharyngeal transition into the esophagus below. The nasal part of the pharynx refers to the respiratory tract, the oral part to the respiratory and digestive ways.

On the inner surface of the pharynx, in the region of its arch at the transition of the upper wall to the posterior one, there is an accumulation of lymphoid tissue - pharyngeal tonsil (tonstlla pharyngealis - adenoidea). On the side walls of the pharynx, at the posterior edge of the inferior nasal concha, there is a pharyngeal opening of the auditory tube (ostium pharyngeum tubae auditivae). The auditory (eustachian) tube connects the pharynx with the drum cavity, facilitates the equalization of external atmospheric pressure and pressure in the cavity of the middle ear (drum cavity). Above and behind the pharyngeal opening of the auditory tube is limited by a tubular roller (torus tubarius), which continues downward into a thin tubal-pharyngeal fold (plica tubopharyngea). Behind the tube roll is a small recess - pharyngeal pocket (recessus pharyngeus). Near the pharyngeal opening of the auditory tube on the right and left walls of the pharynx is the tubal tonsil (tonsilla tubaria), which is the organ of the immune system.

The upper wall of the pharynx is the pharyngeal arch (fornix pharyngis). In the anterior wall of the pharynx, there are two openings at the top - the khoans, which communicate the nasal cavity with the nasopharynx. Between the soft sky at the top and the root of the tongue at the bottom is a yawn, which on the sides is organically lined with a tongue-to-toe tongue in front and a slanting gusset behind. In the anterior wall of the throat part of the pharynx there is an opening leading to the larynx, the entrance to the larynx (aditus laryngis). This hole is limited to the front of the epiglottis, on the sides - cherpalo-non-hydrangeal folds, below - the arytenoid cartilages of the larynx. Between the inner surface of the thyroid cartilage and the scaly palate fold on each side is a recessus - a pear-shaped pocket (recessus piriformis).

The pharyngeal wall is formed by the mucous membrane, compacted submucosal base, muscular membrane and adventitia.

The mucous membrane of the nasopharynx is lined with pseudo-layered ciliate epithelium. In the area of the mouth and larynx, the mucous membrane is covered with multilayered flat epithelium located on its own plate with a high content of elastic fibers. The submucosal base of the nasopharynx and oropharynx is densified, represented by a fibrous plate called the pharyngo-basilar fascia (fascia pharyngobasilaris). At the level of the larynx, the submucosa consists of a loose fibrous connective tissue, containing numerous mucous glands.

The muscular membrane of the pharynx is represented by five striated muscles. Among them are three pharyngeal compressors (constrictors) and longitudinal muscles - pharyngeal lifters.

The upper pharyngeal constrictor (m. Constrictor pharyngis superior) begins on the medial plate of the pterygoid process of the sphenoid bone, as well as on the pterygoid-lower jaw (raphe pterygomandibulare) - a fibrous plate stretched between the pterygoid crooked croiss and the lower jaw. The muscle fibers of the upper constrictor go down and back, where on the median line on the back of the pharynx connect to the fibers of this muscle of the opposite side.

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Muscles of pharynx

Muscle	Start	Attachment	Function	Innervation
Throat compressors
Upper pharyngeal constrictor	Medial plate of pterygoid process of sphenoid bone, pterygo-mandibular suture, lower jaw, root of tongue	On the back surface of the pharynx fuses with a similar muscle the other side	Reduce the lumen of the pharynx	Branch of the pharyngeal plexus
Middle pharynx constrictor	Large and small horn of the hyoid bone	Also
Lower throat constrictor	The lateral surfaces of the thyroid and cricoid cartilage	»»
Throat Lifters
Shilo-pharyngeal muscle	The styloid process of the temporal bone	Lateral wall of pharynx	Raises the pharynx to the top	Branch of pharyngeal nerve
Tubular and pharyngeal muscle	The lower surface of the cartilage of the auditory tube near the pharyngeal opening of it	Also	Raises the pharynx up and laterally	Branch of the pharyngeal plexus

The middle constrictor of the pharynx (m.constructor pharyngis medius) originates from the large and small horns of the hyoid bone. Muscle fibers fan outwardly and upwards, fusing with the fibers of the opposite side on the back wall of the pharynx (along the median line). The upper edge of the middle constrictor is superimposed on the lower part of the upper pharynx constrictor.

The lower constrictor of the pharynx (m.constrictor pharyngis inferior) begins on the lateral surface of the plate of the thyroid glia and on the ring of the prominent cartilage of the larynx.

Muscular bundles fan outwardly, horizontally and upward, cover the lower part of the middle constrictor and grow together with similar bundles of the opposite side along the posterior median line. The lower muscular tufts pass to the back wall of the publisher.

As a result of the fusion of the right and left muscular bundles of the pharynx constrictors, a pharyngeal suture (raphe pharyngis) forms behind the median line. Constrictors of the pharynx narrow its lumen.

To the longitudinal muscles of the pharynx carry two muscles:

The shiglotoccus muscle (m.stylopharyngeus) begins on the styloid process of the temporal bone, goes downward and medially, penetrates the thickness of the lateral wall of the pharynx at the level between the upper and middle constrictors. With a contraction, it raises the pharynx and along with it the larynx.

The tube-pharyngeal muscle (m.salpingopharyngeus) begins on the lower surface of the trumpet of the auditory tube, near its pharyngeal opening. Muscular bundles are directed downward, connected to the neo-pharyngeal muscle and intertwined into the lateral wall of the pharynx. The neo-pharyngeal muscle (m.palatopharyngeus) begins on the palatine aponeurosis.

The pharyngeal and pharyngeal muscles participate in the swallowing act. In this case, the trumpet-pharyngeal muscle pulls the wall of the auditory tube downwards, expands its pharyngeal opening, which facilitates the entry of air into the tympanic cavity and the alignment of the pressure corresponding to the atmospheric one.

Swallowing act

The food lump touches the palate, the root of the tongue and the posterior pharyngeal wall, causing irritation of the receptors. The nervous impulse along the glossopharyngeal nerves enters the swallowing center of the medulla oblongata. Neurons of the center generate impulses directed along trigeminal, lingopharyngeal, vagal and sublingual nerves to the muscles of the oral cavity, tongue, pharynx, esophagus and larynx. The joint contraction of these muscles causes an act of swallowing. Distinguish an arbitrary phase with a duration of 0.7-1.0 s and an involuntary phase (4-6 s). The swallowing act is a continuous alternation of the following phases:

1. the muscles of the soft palate contract, the palatal curtain rises and presses against the vault and posterior wall of the pharynx, separating the nasopharynx from the remaining parts of the pharynx;
2. with the contraction of the muscular diaphragm of the mouth, the larynx rises and shifts anteriorly, the epiglottis closes the entrance to the larynx;
3. with the reduction of the typhoid and sublingual-lingual muscles, the root of the tongue shifts backward, the food lump is pushed through the pharynx into the oropharynx;
4. due to the reduction of the lingual-lingual muscles, part of the food lump, which has entered the mouth of the throat, is separated (cut off) from the food that is still in the oral cavity;
5. when a food lump enters the pharynx, the longitudinal muscles lift the pharynx, pulling it into the food lump;
6. a consecutive top-down contraction of the pharynx constrictors pushes the food lump from the pharynx into the esophagus.