Where does the right thoracic duct collect lymph from? Lymph
thoracic duct I
Thoracic duct (ductus throracicus)
the main lymphatic collector that collects lymph from most of the human body and flows into the venous system. Passes G. p. only, flowing from the right half of the chest, head, neck and right upper limb - it flows into the right. The length of G. p. in an adult is about 40 cm, diameter about 3 mm. The duct is formed in the retroperitoneal tissue at the level of THXII - L II vertebrae by the fusion of large lymphatic trunks. The initial part of the duct () is wide - with a diameter of 7-8 mm. G. p. passes through the diaphragm in the back and is located between the descending aorta and the unpaired vein. Then G. p .
deviates to the left and the aortic arch emerges from under the left edge of the esophagus, slightly above the left clavicle, curves in an arcuate manner and flows into the venous bed at the confluence of the left subclavian and internal jugular veins. In the thoracic duct, incl. at its confluence with the venous system, there are valves that prevent blood from flowing into it. The main research method of G. p. is contrast lymphography .
It is carried out by slowly introducing superfluid iodo-lipol or myodil into the lymphatic vessels of one or both feet. G.'s pathology of the item and clinical practice meets seldom. Gp is of the greatest importance for open and especially closed chest injuries, as well as for various operations on the neck and in the chest cavity. G. p. may be accompanied by an external outflow of chyle (external chylorrhea) or outflow of chyle into the pleural cavity (). The characteristic clinical manifestations of chylothorax are mainly due to compression of the lung, mediastinal displacement with symptoms of respiratory failure (Respiratory failure) and hemodynamic disturbances. The right-sided chylothorax is more pronounced than the left-sided one, which is associated with greater compliance of the left dome of the diaphragm and less pronounced displacement of the organs during the accumulation of chyle in the left pleural cavity. In this case, there is a risk of damage to the recurrent, vagus and phrenic nerves.
1. Small medical encyclopedia. - M.: Medical Encyclopedia. 1991-96 2. First aid. - M.: Great Russian Encyclopedia. 1994 3. Encyclopedic dictionary of medical terms. - M.: Soviet Encyclopedia. - 1982-1984.
Veterinary Encyclopedic Dictionary
thoracic duct- (ductus thoracicus) the largest lymphatic vessel 30-40 cm long. It is formed in the upper abdominal cavity from the confluence of the right and left lumbar trunks. Along the length in the thoracic duct, the abdominal, thoracic and cervical parts are distinguished. AT… … Glossary of terms and concepts on human anatomy
One of the two main lymphatic ducts. Lymph passes through it from both lower extremities, from the lower abdomen, the left half of the chest and head, and also from the left arm. The thoracic duct flows into the left venous angle.
thoracic duct, ductus thoracicus , is formed in the abdominal cavity, in the retroperitoneal tissue, at the level of the XII thoracic - II lumbar vertebrae as a result of fusion right and left lumbar lymphatic trunks,Trunci lumbales dexter et sinister.
Formation of the thoracic duct
These trunks are formed from the fusion of the efferent lymphatic vessels, respectively, of the right and left lumbar lymph nodes.
One to three efferent lymphatic vessels of the mesenteric lymph nodes flow into the initial part of the thoracic duct, which are called intestinal trunks,Trunci intestinales. prevertebral, intercostal, as well as visceral (preaortic) lymph nodes of the chest cavity.
abdominal part,pars abdominalis, the thoracic duct is its initial part. It has the extension - cistern of the thoracic ductcisterna chyli.
chest part,pars thoracica, the longest. It extends from the aortic aperture of the diaphragm to the superior aperture of the chest, where the duct passes into its neck,pars cervicalis.
Arc of the thoracic duct
arcus ductus thoracici, bends around the dome of the pleura from above and behind, and then the mouth of the duct opens into the left venous angle or into the final section of the veins that form it. In about 50% of cases, the thoracic duct has an expansion before flowing into a vein. Also, the duct often bifurcates, and in some cases it flows into the veins of the neck with three or four trunks.
At the mouth of the thoracic duct there is a paired valve that prevents blood from being thrown from a vein. The wall of the thoracic duct, in addition to the inner lining, tunica interna, and outer shell tunica externa, contains the middle (muscular) membrane, tunica media.
In about a third of cases, there is a doubling of the lower half of the thoracic duct: next to its main trunk, there is an additional thoracic duct. Sometimes local splitting (doubling) of the thoracic duct is found.
The thoracic duct of the lymphatic system - plays the role of one of the main lymphatic "collectors", which performs the transport of lymphatic fluid from:
All organs of the abdominal cavity.
Both legs.
Small pelvis.
Left side of the upper limb.
Some parts of the heart.
Lateral parts of the head and neck.
Thoracic lymphatic duct system
Its length is about 34 - 45 centimeters, and the diameter of the lumen is variable throughout its length. The vessel includes two extensions: one at the very beginning and the second begins closer to the end of the duct.
It is formed due to the association of a group of lymphatic vessels at the level of the second lumbar vertebra. At the beginning there is a small thickening - the cistern of the thoracic duct. It should be noted that the boundaries of its beginning, as well as the presence of an initial expansion, its size and shape are individual characteristics and in some cases may change (peculiarities of formation during the period of being in the womb or as a result of secondary pathological processes).
According to the topographic criterion, the duct is divided into thoracic, abdominal, cervical parts.
Thoracic lymphatic duct
In this section, the duct is located in the region of the posterior mediastinum, between the aorta and the azygous vein, with the transition to the anterior surface of the vertebrae. Further, it goes up and, at the level of the third thoracic vertebra, occupies a left-sided position in relation to the esophagus, and so it follows up to the seventh cervical vertebra.
It can be bifurcated, however, by the transition to the abdominal part, it will reconnect. In this part of the duct, they begin to add to its composition:
Lymphatic vessels of small and medium caliber emerging from the intercostal spaces.
Bronchomediastinal shaft.
Cervical - begins with the seventh cervical vertebra and branches in the fiber.
Abdominal thoracic duct
The lumbar and intestinal trunks are the main efferent vessels that collect the intercellular fluid from the corresponding regional lymph nodes after its preliminary cleaning. After that, they both go to the cistern of the thoracic duct and flow into it, thereby forming the abdominal part.
Functions of the lymphatic duct
The main function of this anatomical structure is to transport the bodice, which has been previously cleaned in the lymph nodes, and return it back to the bloodstream, by transporting it to the venous angle. The flow of lymphatic fluid is carried out due to:
1. Pressure differences between large venous vessels and the chest cavity.
2. Due to the presence of valves in the duct itself.
3. As a result of the compression action of the diaphragmatic legs.
Methods for studying the lymphatic duct
A modern method for assessing the state of the thoracic duct, its patency, integrity is lymphangiography using radiopaque substances.
The technique consists in introducing a radiopaque substance through access, in this case, an iodine-containing drug (myodil, urographin, etc.). Then an x-ray is taken. In the picture, due to the contrast, the corresponding anatomical structure, its contours, real dimensions, narrowing, expanding, etc. will be visible.
What diseases can be associated with damage to the lymphatic duct?
In modern realities, the defeat of the thoracic duct as a result of the course of any diseases is an extremely rare case and is practically not observed in everyday practice. Another thing is damage to this structure in traumatic lesions of the chest, both open and closed injuries, or when performing surgical interventions in the neck or on organs located close to the place where the main branches of the duct pass.
As a result of damage to the duct, external or internal chylorrhea develops (the contents begin to flow out or out, or begin to fill the free cavities inside the body).
The most dangerous condition, as a result of trauma to the vessel, is chylothorocas - the release of contents into the pleural cavity.
Characterized by:
Difficulty inhaling.
Delay of one of the halves of the chest during the act of breathing.
Increasing respiratory failure.
A change in the circulatory system.
development of acidosis.
Quite often, inflammation of the walls of the thoracic duct of the lymphatic system can be observed in patients with tuberculosis infection or filariasis. The result is swelling of the duct wall, which leads to narrowing of the vessel and, as a result, impaired patency. What can lead to development:
1. Chyluria.
2. Chylothorax.
3. Chylopericardium.
4. Chyloperitoneum.
Malignant and benign neoplasms can disrupt lymphodynamics, by squeezing the lymphatic vessels, as a result of prolonged compression and impaired patency, the contents of the duct may leak into the pleural cavity or into the abdominal cavity (development of chyloperitoneum). In such cases, surgery is urgently needed.
Treatment
Treatment of a variety of lesions of the thoracic lymphatic duct is primarily focused on:
Elimination of the underlying disease that led to the violation of lymphodynamics.
Restoration of the patency of the vessel and its integrity.
Elimination of chylorrhea.
Removal of residual lymph from all cavities.
Carrying out detoxification therapy.
Initially, conservative and minimally invasive methods of treatment are used. To eliminate the expiration of the patient's bodices, they are transferred to parenteral nutrition (in / in solutions of amino acids, glucose, etc.) for a period of 10 to 15 days.
If the lymph flows into the pleural cavity, aspiration drainage of this cavity is performed.
If such treatment is ineffective, it is necessary to proceed with those aimed at restoring the natural flow of the lymph by ligating the lymphatic duct above and below the interruption site, followed by an attempt to restore the vascular wall at the site of deformation.
Video: mammary gland lymphatic drainage
After the lymph has passed through the lymph nodes, it is collected in lymph trunks and lymphatic ducts. A person has six such large trunks and ducts. Three of them flow into the right and left venous angles.
The main and largest lymphatic vessel is the thoracic duct. Through the thoracic duct, lymph flows from the lower extremities, organs and walls of the pelvis, the left side of the chest cavity and the abdominal cavity. Through the right subclavian trunk, lymph flows from the right upper limb, into the right jugular trunk from the right half of the head and neck. From the organs of the right half of the chest cavity, lymph flows into the right bronchomediastinal trunk, which flows into the right venous angle or into the right lymphatic duct. Accordingly, lymph flows through the left subclavian trunk from the left upper limb, and from the left half of the head and neck through the left jugular trunk, from the organs of the left half of the chest cavity, lymph flows into the left bronchomediastinal trunk, which flows into the thoracic duct.
thoracic lymphatic duct
The formation of the thoracic duct occurs in the abdominal cavity, in the retroperitoneal tissue at the level of the 12th thoracic and 2nd lumbar vertebrae during the connection of the right and left lumbar lymphatic trunks. The formation of these trunks occurs as a result of the fusion of the efferent lymphatic vessels of the right and left lymph nodes of the lower back. From 1 to 3 efferent lymphatic vessels belonging to the mesenteric lymph nodes, called intestinal trunks, flow into the initial part of the thoracic lymphatic duct. This is observed in 25% of cases.
The lymphatic efferent vessels of the intercostal, prevertebral, and visceral lymph nodes drain into the thoracic duct. Its length is from 30 to 40 cm.
The initial part of the thoracic duct is its abdominal part. In 75% of cases, it has an ampulla-shaped, cone-shaped or spindle-shaped extension. In other cases, this beginning is a reticular plexus, which is formed by the efferent lymphatic vessels of the mesenteric, lumbar and celiac lymph nodes. This extension is called a cistern. Usually the walls of this tank are fused with the right leg of the diaphragm. During breathing, the diaphragm compresses the thoracic duct, facilitating the flow of lymph.
The thoracic lymphatic duct from the abdominal cavity enters the chest cavity through the aortic opening and enters the posterior mediastinum. There it is located on the anterior surface of the spinal column, between the unpaired vein and the thoracic aorta, behind the esophagus.
The thoracic portion of the thoracic duct is the longest. It originates at the aortic opening of the diaphragm and goes to the upper aperture of the chest, passing into the cervical duct. In the region of the 6th and 7th thoracic vertebrae, the thoracic duct deviates to the left, and exits from under the left edge of the esophagus at the level of the 2nd and 3rd thoracic vertebrae, rising up behind the left subclavian and left common carotid arteries and the vagus nerve. In the superior mediastinum, the thoracic duct runs between the left mediastinal pleura, esophagus, and spinal column. The cervical part of the thoracic lymphatic duct has a bend, forming an arc at the level of 5-7 cervical vertebrae, which goes around the dome of the pleura from above and slightly behind, and then opening with the mouth into the left venous angle or into the final section of the veins that form it. In half of the cases, the thoracic lymphatic duct expands before flowing into a vein, in some cases it bifurcates or has 3-4 trunks that flow into the venous angle or into the terminal sections of the veins that form it.
The ingress of blood from the vein into the duct is prevented by a paired valve located at the mouth of the thoracic lymphatic duct. Also, along the entire length of the thoracic duct, there are from 7 to 9 valves that prevent the reverse movement of lymph. The walls of the thoracic duct have a muscular outer shell, the muscles of which contribute to the movement of lymph to the mouth of the duct.
In some cases (approximately 30%), the lower half of the thoracic duct has a doubling.
Right lymphatic duct
The right lymphatic duct is a vessel, 10 to 12 mm long. The broncho-mediastinal trunk, jugular trunk and subclavian trunk flow into it. It has an average of 2-3 sometimes more trunks, flowing into the angle formed by the right subclavian vein and the right internal jugular vein. In rare cases, the right lymphatic duct has one mouth.
jugular trunks
The right and left jugular trunks originate in the efferent lymphatic vessels of the lateral deep cervical right and left lymph nodes. Each consists of one vessel or several short ones. The right jugular trunk enters the right venous angle, into the final part of the right internal jugular vein, or forms the right lymphatic duct. The left jugular trunk enters the left venous angle, the internal jugular vein, or the cervical part of the thoracic duct.
Subclavian trunks
The right and left subclavian trunks originate from the efferent lymphatic vessels belonging to the axillary lymph nodes, most often the apical ones. These trunks go to the right and left venous corner, respectively, in the form of one trunk or several small ones. The right subclavian lymphatic trunk flows into the right venous angle, or into the right subclavian vein, the right lymphatic duct. The left subclavian lymphatic trunk flows into the left venous angle, the left subclavian vein, and in some cases it flows into the terminal part of the thoracic duct.
The right lymphatic duct, ductus lymphaticus dexter, has a length of no more than 10-12 mm and is formed from the confluence of three trunks: truncus jugularis dexter, which receives lymph from the right region of the head and neck, truncus subclavius dexter, which carries lymph from the right upper limb, and truncus bronchomediastinalis dexter , which collects lymph from the walls and organs of the right half of the chest and the lower lobe of the left lung. The right lymphatic duct drains into the right subclavian vein. Quite often it is absent, in which case the three trunks listed above independently flow into the subclavian vein
4. Spinal cord: external structure, topography The spinal cord, medulla spinalis (Fig. 878, 879), has a relatively simple structural principle and a pronounced segmental organization compared to the brain. It provides connections between the brain and the periphery and carries out segmental reflex activity.
The spinal cord lies in the spinal canal from the upper edge of the 1st cervical vertebra to the 1st or upper edge of the 2nd lumbar vertebra, repeating to a certain extent the direction of curvature of the corresponding parts of the spinal column. In a fetus of 3 months, it ends at the level of the V lumbar vertebra, in a newborn - at the level of the III lumbar vertebra.
The spinal cord without a sharp border passes into the medulla oblongata at the exit of the first cervical spinal nerve. Skeletotopically, this border runs at the level between the lower edge of the foramen magnum and the upper edge of the 1st cervical vertebra. Below, the spinal cord passes into the cerebral cone, conus medullaris, continuing into the terminal thread (spinal), filum terminate (spinate), which has a diameter of up to 1 mm and is a reduced part of the lower spinal cord. The terminal thread, with the exception of its upper sections, where there are elements of the nervous tissue, is a connective tissue formation. Together with the hard shell of the spinal cord, it penetrates the sacral canal and attaches at its end. That part of the terminal thread, which is located in the cavity of the dura mater and is not fused with it, is called the internal terminal thread, filum terminate internum; the rest of it, fused with the dura mater, is the outer terminal thread (hard shell), filum terminale externum (durale). The terminal thread is accompanied by the anterior spinal arteries and veins, as well as one or two roots of the coccygeal nerves.
The spinal cord does not occupy the entire cavity of the spinal canal: between the walls of the canal and the brain there remains a space filled with adipose tissue, blood vessels, meninges and cerebrospinal fluid.
The length of the spinal cord in an adult ranges from 40 to 45 cm, the width is from 1.0 to 1.5 cm, and the average weight is 35 g.
There are four surfaces of the spinal cord: a somewhat flattened anterior, slightly convex posterior, and two lateral, almost rounded, passing into the anterior and posterior.
The spinal cord does not have the same diameter throughout. Its thickness increases slightly from bottom to top. The largest size in diameter is noted in two spindle-shaped thickenings: in the upper section - this is the cervical thickening, intumescentia cervicalis, corresponding to the exit of the spinal nerves going to the upper limbs, and in the lower section - this is the lumbosacral thickening, intumescentia lumbosacralis - the place where the nerves exit to lower limbs. In the region of the cervical thickening, the transverse size of the spinal cord reaches 1.3-1.5 cm, in the middle of the thoracic part - 1 cm, in the region of the lumbosacral thickening - 1.2 cm; the anteroposterior size in the area of thickening reaches 0.9 cm, in the thoracic part - 0.8 cm.
The cervical thickening begins at the level of the III-IV cervical vertebra, reaches the II thoracic vertebra, reaching the greatest width at the level of the V-VI cervical vertebra (at the height of the fifth sixth cervical spinal nerve). The lumbosacral thickening extends from the level of the IX-X thoracic vertebra to the 1st lumbar, its greatest width corresponds to the level of the XII thoracic vertebra (at the height of the third lumbar spinal nerve).
The shape of the transverse sections of the spinal cord at different levels is different: in the upper part the section has the shape of an oval, in the middle part it is rounded, and in the lower part it approaches a square.
On the anterior surface of the spinal cord, along its entire length, there is a deep anterior median fissure, fissura mediana ventralis (anterior) (Fig. 880-882, see Fig. 878), into which the fold of the pia mater protrudes - the intermediate cervical septum, septum cervicale intermedium. This gap is less deep at the upper and lower ends of the spinal cord and is most pronounced in its middle sections.
On the posterior surface of the brain there is a very narrow posterior median sulcus, sulcus medianus dorsalis, into which a plate of glial tissue penetrates - the posterior median septum, septum medianum dorsale. The fissure and groove divide the spinal cord into two halves - right and left. Both halves are connected by a narrow bridge of brain tissue, in the middle of which is the central canal, canalis centralis, of the spinal cord.
On the lateral surface of each half of the spinal cord are two shallow grooves. The anterolateral groove, sulcus ventrolateralis, is located outward from the anterior median fissure, more distant from it in the upper and middle parts of the spinal cord than in its lower part. The posterolateral sulcus, sulcus dorsolateralis, lies outward from the posterior median sulcus. Both sulci run along almost the entire length of the spinal cord.
In the cervical and partly in the upper thoracic regions, between the posterior median and posterolateral grooves, there is an unsharply pronounced posterior intermediate groove, sulcus intermedius dorsalis (see Fig. 881).
In the fetus and newborn, a rather deep anterior intermediate sulcus is sometimes found, which, following the anterior surface of the upper sections of the cervical spinal cord, is located between the anterior median fissure and the anterolateral sulcus.
Anterior radicular filaments, fila radicularia, which are processes of motor cells, emerge from or near the anterolateral sulcus. The anterior root filaments form the anterior root (motor), radix ventralis (motoria). The anterior roots contain centrifugal (efferent) fibers that conduct motor and autonomic impulses to the periphery of the body: to striated and smooth muscles, glands, etc.
The posterolateral groove includes the posterior radicular filaments, consisting of processes of cells that lie in the spinal ganglion. The posterior radicular threads form the posterior root (sensitive), radix dorsalis. The posterior roots contain afferent (centripetal) nerve fibers that conduct sensory impulses from the periphery, that is, from all tissues and organs of the body, to the central nervous system.
The spinal node (sensitive), ganglion spinale (see Fig. 879, 880), is a spindle-shaped thickening located on the back root. It is a cluster of mostly pseudo-unipolar nerve cells. The process of each such cell is divided in a T-shape into two processes: a long peripheral one is sent to the periphery as part of the spinal nerve, n. spinalis, and ends in a sensitive nerve ending; a short central one follows as part of the posterior root to the spinal cord (see Fig. 947). All spinal nodes, with the exception of the node of the coccygeal root, are tightly surrounded by the dura mater; the nodes of the cervical, thoracic and lumbar regions lie in the intervertebral foramina, the nodes of the sacral region lie inside the sacral canal.
Ascending pathways of the spinal cord and brain; right hemisphere (semi-schematically).
The direction of the roots is not the same: in the cervical region they depart almost horizontally, in the thoracic region they go obliquely downward, in the lumbosacral region they follow straight down (see Fig. 879).
The anterior and posterior roots of the same level and one side immediately outward from the spinal node are connected, forming the spinal nerve, n. spinalis, which is thus mixed. Each pair of spinal nerves (right and left) corresponds to a specific area - a segment - of the spinal cord.
Therefore, there are as many segments in the spinal cord as there are pairs of spinal nerves.
The spinal cord is divided into five parts: the cervical part, pars cervicalis, the thoracic part, pars thoracica, the lumbar part, pars lumbalis, the sacral part, pars sacralis, and the coccygeal part, pars coccygea (see Fig. 879). Each of these parts includes a certain number of segments of the spinal cord, segmenta medullae spinalis, i.e. sections of the spinal cord that give rise to one pair of spinal nerves (right and left).
The cervical part of the spinal cord consists of eight cervical segments, segmenta medullae spinalis cervicalia, the thoracic part - 12 thoracic segments, segmenta medullae spinalis thoracicae, the lumbar part - five lumbar segments, segmenta medullae spinalis lumbalia, the sacral part - five sacral segments, segmenta medullae spinalis sacralia, and, finally, the coccygeal part is made up of one to three coccygeal segments, segmenta medullae spinalis coccygea. A total of 31 segments.
outer base of the skull
The occipital bone, the posterior surfaces of the pyramids, and the temporal bones take part in the formation of the posterior cranial fossa.
Between the back of the Turkish saddle and the large occipital foramen there is a slope.
The internal auditory (right and left) opening opens into the posterior cranial fossa, from which the vestibulocochlear nerve (VIII pair) emerges, and the facial nerve (VII pair) exits from the canal of the facial nerve. The tongue-pharyngeal (IX pair), vagus (X pair) and accessory (XI pair) nerves exit through the jugular foramen of the base of the skull. The nerve of the same name passes through the canal of the hypoglossal nerve - the XII pair. From the cranial cavity, in addition to the nerves, the internal jugular vein exits through the jugular foramen, passing into the sigmoid sinus. The formed foramen magnum connects the cavity of the posterior cranial fossa with the spinal canal, at the level of which the medulla oblongata passes into the spinal cord.
The outer base of the skull (basis cranii extema) in its anterior section is covered with facial bones (there is a bony palate bounded in front by the alveolar process of the upper jaw and teeth), and the posterior section is formed by the outer surfaces of the sphenoid, occipital and temporal bones
In this area there are a large number of holes through which the vessels and nerves pass, providing blood supply to the brain. The central part of the outer base of the skull is occupied by a large occipital foramen, on the sides of which the occipital condyles are located. The latter are connected to the first vertebra of the cervical spine. The exit from the nasal cavity is represented by paired openings (choanas), passing into the nasal cavity. In addition, on the outer surface of the base of the skull are the pterygoid processes of the sphenoid bone, the external opening of the carotid canal, the styloid process, the stylomastoid foramen, the mastoid process, the musculo-tubal canal, the jugular foramen and other formations.
In the skeleton of the facial skull, the central place is occupied by the nasal cavity, eye sockets, oral cavity, infratemporal and pterygo-palatine fossae
2.hard and soft palate
The oral cavity itself is bounded from above by the hard palate and part of the soft palate, from below - by the tongue together with the muscles that form the bottom of the oral cavity, in front and from the sides - by the dentition and gums. Behind, the boundary of the cavity is the soft palate with a tongue that separates the mouth from the pharynx. In newborns, the oral cavity is short and low due to the absence of teeth. As the dentition develops, it gradually acquires a definitive volume. In people in adulthood, the shape of the oral cavity has individual characteristics. In short-headed ones, it is wider and higher than in long-headed ones.
Depending on the shape of the hard palate, the height of the alveolar processes, the vault (dome) formed by the upper wall of the oral cavity can be of different heights. In people with a narrow and high face (dolichocephalic type), the arch of the palate is usually high, in people with a wide and low face of the brachycephalic type) the arch of the palate is flattened. It has been noticed that people with a singing voice have a higher vault of the sky. With an increased volume of the oral cavity, one of the resonator cavities is the physical basis for the development of vocal data.
The soft palate hangs freely, fixed at the top along the bony elements of the hard palate. With calm breathing, it separates the oral cavity from the pharynx. At the moment of swallowing food, the soft palate is set horizontally, separating the oropharynx from the nasopharynx, i.e., isolating the food tract from the respiratory tract. The same happens during the implementation of vomiting movements. The mobility of the soft palate is provided by its muscles, which are able to strain it, raise and lower it. The action of this muscle is carried out automatically.
The bottom of the oral cavity, or its lower base, consists of soft tissues, the support of which is mainly the maxillohyoid and chin muscles.
The functions of the mouth are regulated by a complex nervous apparatus in which nerve fibers take part: motor secretory, sensory and gustatory.
The oral cavity performs a variety of physiological functions: here the food is subjected to mechanical grinding, here it begins to undergo chemical processing (exposure to saliva). With the help of ptyalin contained in saliva, the saccharification of starchy substances begins. The soaking and coating with saliva makes hard food easy to swallow; without saliva, swallowing would not be possible. The work of the salivary glands is closely related to stimuli in the external environment, and is an innate unconditioned reflex. In addition to this unconditioned reflex, salivation can also be a conditioned reflex, i.e., saliva can be released with an irritant coming from the eye - light, ear - acoustic, skin - tactile.
Excitation of the nervous apparatus of the salivary glands, i.e., increased salivation, can occur when certain chemicals enter the oral cavity (for example, pilocarpine), with various inflammatory processes in the oral cavity (for example, with stomatitis), with damage to other organs (for example, stomach, intestines), with trigeminal neuralgia. Inhibition of the nervous apparatus of the salivary glands, i.e., a decrease in salivation, occurs under the influence of certain chemicals (atropine) and under the influence of reflex moments (fear, excitement).
The oral cavity is a checkpoint where food substances are tested using the sense of taste and smell. In the numerous taste buds of the tongue, fibers of the taste nerve terminate. With indigestion, the patient feels a bad taste in the mouth, the tongue is covered with plaque - it becomes coated. According to Pavlov, this is a self-healing reflex on the part of the body; a reflex occurs in the intestine, which is transmitted through the trophic nerves to the tongue, causing a loss of taste, i.e., abstinence from food, thereby ensuring rest for the digestive canal.
The first act of swallowing takes place in the oral cavity. When sucking, the soft palate descends and closes the oral cavity from behind, in front the oral cavity is closed by the action of m. orbicularis oris, which lengthens the baby's lips like a trunk around the nipple or horn. With cleft lip intact m. orbicularis oris is disturbed, and the act of sucking is difficult.
The sucking act can continue indefinitely, since with the lowered palatine curtain, nasal breathing occurs normally.
During the act of swallowing, the root of the tongue descends, the soft palate rises to a horizontal position, separating the nasopharyngeal cavity from the oral cavity. The tongue pushes food into the formed funnel. At the same time, the glottis closes, food comes into contact with the walls of the pharynx, exciting the contraction of the pharyngeal muscles and constrictors, which push the bolus of food further into the esophagus.
The oral cavity is involved in speech: speech is impossible without the participation of the tongue. During phonation, the soft palate rises and falls to regulate the nasal resonator. This explains the complications during sucking, swallowing and phonation, which entail fissured defects of the palate, paralysis of the palatine curtain, etc.
The oral cavity is also used for breathing.
In the oral cavity there is always a large number of microorganisms and their associations. These various microbes, mixing with saliva and food debris, cause a number of chemical processes in the mouth, the deposition of calculus on the teeth, in the glands, etc. Hence the need for oral hygiene becomes clear.
3) Superior vena cava and brachiocephalic veins
The brachiocephalic and superior vena cava are located in the tissue of the anterior mediastinum directly behind the thymus gland, and the superior vena cava, in addition, lies behind the anterior medial section of the right mediaetinal pleura, and below - inside the pericardial cavity. The right and left brachiocephalic veins arise from the confluence of the respective subclavian and internal jugular veins behind the sternoclavicular joints.
V. brachiocephalica dextra is located behind the right half of the sternum handle from the right sternoclavicular joint to the attachment of the cartilage of the 1st rib to the sternum, where the right and left brachiocephalic veins, having merged with each other, form the superior vena cava. To the anterior outer-lower part of the right brachiocephalic vein, especially if it is long, and the medinastinal pleura adjoins its lateral surface. The right phrenic nerve runs between the pleura and vein. Behind and medial to the right brachiocephalic vein lies the brachiocephalic trunk, behind the right vagus nerve.
V. brachiocephalica sinistra is located transversely or obliquely behind the handle of the sternum, projecting from the left sternoclavicular joint to the junction of the cartilage of the right I rib with the sternum or at any point below, to the level of attachment of the upper edge of the second costal cartilage to the sternum. The thymus gland is adjacent to the vein in front, the aortic arch, the brachiocephalic trunk and the left common carotid artery are behind the vein, and the perinarard is below. V. intercostalis superior sinistra flows into the left brachiocephalic vein or into the left venous angle, which goes forward from the posterior mediastinum, located between the aortic arch and the left mediastinal pleura. This vein serves as a guide for ligation of the ductus arteriosus, which is located below the vein.
V. cava superior goes from top to bottom, lies behind the right edge of the sternum in the area between the cartilages of the 1st and 3rd ribs and enters the pericardial cavity at the level of the second intercostal space. Here, a large v usually flows into it from behind. Azygos
The upper part of the superior vena cava is located in the tissue of the anterior mediastinum to the right of the ascending aorta and to the left of the right mediastinal pleura. Between the vein and the pleura, the right phrenic nerve is directed downward, accompanied by a. and v. pericardiacophrenicae. The lower part of the vein is located in the pericardial cavity and lies anterior to the root of the right lung and to the right of the aorta. Lymphatic vessels and anterior mediastinal lymph nodes adjoin the extrapericardial part of the superior vena cava, as well as both brachiocephalic veins. Outside the pericardial cavity, from the mouth of the superior vena cava to the right pulmonary artery, there is a sail-shaped ligament, which circularly covers the right pulmonary artery with two leaves and firmly connects the artery with the vein. The veins of the mediastinum and neck (vv. mediastinales, thymicae, pericardiacae, bronchiales, tracheales, thoracicae internae, vertebrales and branches of the plexus thyreoi-deus impar) flow into the right and left brachiocephalic veins, as well as into the superior vena cava.
4. Hypoglossal nerve, its core
The hypoglossal nerve is motor (Fig. 9.10). Its nucleus is located in the medulla oblongata, while the upper part of the nucleus is located under the bottom of the rhomboid fossa, and the lower one descends along the central canal to the level of the beginning of the pyramidal tract decussation. The nucleus of the XII cranial nerve consists of large multipolar cells and a large number of fibers located between them, by which it is divided into 3 more or less separate cell groups. The axons of the cells of the nucleus of the XII cranial nerve gather into bundles that penetrate the medulla oblongata and emerge from its anterior lateral groove between the inferior olive and the pyramid. Subsequently, they leave the cranial cavity through a special hole in the bone - the hypoglossal nerve canal (canalis nervi hypoglossi), located above the lateral edge of the foramen magnum, forming a single trunk.
Coming out of the cranial cavity, the XII cranial nerve passes between the jugular vein and the internal carotid artery, forms a hyoid arch, or loop (ansa cervicalis), passing here in close proximity to the branches of the spinal nerves coming from the three upper cervical segments of the spinal cord and innervating the muscles, attached to the hyoid bone. In the future, the hypoglossal nerve turns forward and is divided into lingual branches (rr. linguales), which innervate the muscles of the tongue: hyoid-lingual (t. hypoglossus), syllable (t. styloglossus) and chin-lingual (t. genioglossus) y and also longitudinal and transverse muscles of the tongue (t. longitudinalis and t. transversus linguae).
When the XII nerve is damaged, peripheral paralysis or paresis of the same half of the tongue occurs (Fig. 9.11), while the tongue in the oral cavity shifts to the healthy side, and when protruding from the mouth it deviates towards the pathological process (the tongue "points to the focus"). This happens due to the fact that the t. genioglossus of the healthy side pushes the homolateral half of the tongue forward, while its paralyzed half lags behind and the tongue turns in its direction. The muscles of the paralyzed side of the tongue atrophy over time, become thinner, while the relief of the tongue on the side of the lesion changes - it becomes folded, "geographical".
1. Muscles of the forearm
back group
Surface layer
The long radial extensor of the wrist (m. extensor carpi radialis longus) (Fig. 116, 118) flexes the forearm at the elbow joint, extends the hand and takes part in its abduction. The muscle has a fusiform shape and is distinguished by a narrow tendon, significantly exceeding the length of the abdomen. The upper part of the muscle is covered by the brachioradialis muscle. Its point of origin is located on the lateral epicondyle of the humerus and the lateral intermuscular septum of the shoulder fascia, and the attachment point is on the dorsum of the base of the second metacarpal bone.
The short radial extensor of the wrist (m. extensor carpi radialis brevis) unbends the hand, slightly retracting it. This muscle is slightly covered by the long radial extensor of the wrist, starts from the lateral epicondyle of the humerus and the fascia of the forearm, and is attached to the dorsal surface of the base of the III metacarpal bone.
1 - biceps muscle of the shoulder;
2 - shoulder muscle;
4 - aponeurosis of the biceps muscle of the shoulder;
5 - round pronator;
6 - brachioradialis muscle;
7 - radial flexor of the hand;
9 - long palmar muscle;
10 - superficial finger flexor;
11 - long flexor of the thumb;
12 - short palmar muscle;
13 - palmar aponeurosis
Muscles of the forearm (front view):
1 - shoulder muscle;
2 - supinator;
3 - tendon of the biceps muscle of the shoulder;
4 - long radial extensor of the wrist;
5 - deep finger flexor;
6 - brachioradialis muscle;
7 - long flexor of the thumb;
8 - round pronator;
10 - square pronator;
11 - muscle that opposes the thumb of the hand;
12 - muscle leading the little finger;
13 - short flexor of the thumb;
14 - tendons of the deep flexor of the fingers;
15 - tendon of the long flexor of the thumb;
16 - tendons of the superficial flexor of the fingers
Muscles of the forearm (front view):
1 - round pronator;
2 - tendon of the biceps muscle of the shoulder;
3 - supinator;
4 - interosseous membrane;
5 - square pronator
Muscles of the forearm (back view):
1 - brachioradialis muscle;
2 - triceps muscle of the shoulder;
3 - long radial extensor of the wrist;
6 - extensor of the fingers;
8 - extensor of the little finger;
9 - a long muscle that removes the thumb of the hand;
10 - short extensor of the thumb;
11 - extensor retinaculum;
12 - long extensor of the thumb;
13 - extensor tendons of the fingers
Muscles of the forearm (back view):
1 - arch support;
2 - deep finger flexor;
3 - a long muscle that abducts the thumb of the hand;
4 - long extensor of the thumb;
5 - short extensor of the thumb;
6 - extensor of the index finger;
7 - extensor retinaculum;
8 - extensor tendons of the fingers
The extensor digitorum (m. extensor digitorum) unbends the fingers and takes part in the extension of the hand. The abdomen of the muscle has a fusiform shape, the direction of the bundles is characterized by a two-pinnate shape.
Its point of origin is located on the lateral epicondyle of the humerus and the fascia of the forearm. In the middle of its length, the abdomen passes into four tendons, which on the back of the hand pass into tendon extensions, and those with their middle part are attached to the base of the middle phalanges, and with their lateral parts - to the base of the distal phalanges of the II–V fingers.
The extensor of the little finger (m. extensor digiti minimi) (Fig. 118) unbends the little finger. A small fusiform muscle that originates on the lateral epicondyle of the humerus and inserts at the base of the distal phalanx of the fifth finger (little finger).
The ulnar extensor of the wrist (m. extensor capiti ulnaris) (Fig. 118) unbends the hand and abducts it to the ulnar side. The muscle has a long fusiform abdomen, begins on the lateral epicondyle of the humerus and fascia of the forearm, and is attached to the base of the dorsal surface of the fifth metacarpal bone.
deep layer
the upinator (m. supinator) (Fig. 116, 117, 119) rotates the forearm outwards (supinates) and takes part in the extension of the arm in the elbow joint. The muscle has the shape of a thin rhomboid plate. Its point of origin is on the crest of the supinator of the ulna, the lateral epicondyle of the humerus and the capsule of the elbow joint. The place of attachment of the arch support is located on the lateral, anterior and posterior sides of the upper third of the radius.
The long muscle that abducts the thumb of the hand (m. abductor pollicis longus) (Fig. 118, 119) abducts the thumb and takes part in the abduction of the brush. The muscle is partially covered by the extensor of the fingers and the short radial extensor of the wrist, has a flat bipennate abdomen, turning into a thin long tendon. It originates on the posterior surface of the ulna and radius and inserts at the base of the first metacarpal.
Short extensor thumb brush (m. extensor pollicis brevis) (Fig. 118, 119) abducts the thumb and unbends its proximal phalanx. The point of origin of this muscle is located on the posterior surface of the neck of the radius and the interosseous membrane, the attachment point is on the basis of the proximal phalanx of the thumb and the capsule of the first metacarpophalangeal joint.
The long extensor of the thumb (m. extensor pollicis longus) (Fig. 118, 119) unbends the thumb, partly retracting it. The muscle has a spindle-shaped abdomen and a long tendon. The starting point is located on the posterior surface of the body of the ulna and the interosseous membrane, the attachment point is at the base of the distal phalanx of the thumb.
The extensor of the index finger (m. extensor indicis) (Fig. 119) unbends the index finger. This muscle is sometimes absent. It is covered by the extensor of the fingers, has a narrow, long, spindle-shaped abdomen.
It starts on the posterior surface of the body of the ulna and the interosseous membrane, and is attached to the dorsum of the middle and distal phalanges of the index finger.
2.Male and female urethra
The male urethra, urethra masculina, has an average length of up to 20-23 cm, is divided into three parts: prostatic, pars prostatica, membranous, pars membranacea, and spongy, pars spongiosa.
It starts from the bladder with the internal opening of the urethra, ostium urethrae internum, and extends to the external opening of the urethra, ostium urethrae externum. located at the top of the glans penis. The part of the urethra from the internal opening to the seminal hillock, colliculus seminalis, is called the posterior urethra, the distal part is the anterior urethra. The urethra along its course forms an S-shaped bend: the first, prostatic, part, going from top to bottom, forms a convex posterior arc with the membranous and the beginning of the spongy part, enveloping the pubic symphysis from below, the subpubic curvature; the initial part of the spongy part of the urethra, passing through the section of the penis fixed by the ligaments, forms with its hanging part the second knee, the bulge directed anteriorly, the prepubic curvature. The division of the urethra into these three parts is determined by the characteristics of the formations that surround it. The prostatic part, pars prostatica, penetrates the prostate gland from above, from behind down and forward. It has a length of 3–4 cm and begins in a narrow part from the internal opening of the urethra (the first bottleneck of the canal). In the middle of its length, an expansion of the urethra (the first expansion) is formed. On the back wall of the mucous membrane, starting from the uvula of the bladder, uvula vesicae urinariae, which is a longitudinal roller on the surface of the triangle of the bladder, there is a median fold - the crest of the urethra, crista urethralis. In the middle of its length, the crest passes into a longitudinally located seed mound, colliculus seminalis: distally, this fold reaches the membranous part. At the top of the seed mound there is a longitudinally located pocket - the prostate uterus, utriculus prostaticus.
On each side of the crest of the urethra are the mouths of the ejaculatory ducts. On both sides of the seminal hillock, between it and the wall of the urethra, the mucous membrane of the urethra forms folds; in the groove limited by them, which is called the prostatic sinus, sinus prostaticus, the mouths of the prostatic ducts, ductuli prostatici, open; part of the grooves sometimes opens on the seed mound itself.
The membranous part, pars membranacea, is the shortest part of the urethra, has a length of 1.5–2 cm. It is tightly fixed in the urogenital diaphragm through which it passes. The proximal section of this part of the canal is the narrowest throughout the entire canal (the second bottleneck); the distal section, passing into the spongy part, becomes wider. The internal opening of the urethra and the proximal part of the prostate part of it are covered by a smooth muscle internal sphincter of the urethra, the fibers of which are a continuation of the muscles of the bladder triangle and are woven into the muscular substance of the prostate gland. The membranous part of the canal and the distal part of the prostate cover the striated muscle fibers of the sphincter of the urethra, m. sphincter urethrae. These fibers are part of the deep transverse muscle of the perineum, due to which the membranous part is fixed at the exit from the pelvis and its mobility is very small; this is further enhanced by the fact that part of the muscle fibers of the urogenital diaphragm passes to the prostatic part and to the spongy and, thus, the membranous part becomes even less mobile.
The spongy part, pars spongiosa, is the longest part of the urethra, has a length of 17–20 cm. It begins with its widest section (second extension), embedded in the bulb of the penis, the bulbous fossa, and, as indicated, reaches at the top of the head spongy body of the external opening of the urethra, representing the third bottleneck of the canal. The orifices of the bulbourethral glands open into the posterior (lower) wall of the bulbous part. Proximal to the external opening of the urethra is an extension located in the sagittal direction - the navicular fossa of the urethra. fossa navicularis urethrae, which is the third extension along the canal. The mucous membrane of the upper wall here forms a flap of the navicular fossa, valvula fossae navicularis, transversely located on the upper wall of the fossa, thereby separating the pocket open anteriorly. On the upper wall of the spongy part, transverse folds lie in two rows, limiting the small (0.5 mm), anteriorly open lacunae of the urethra, lacunae urethrales, into which the tubular-alveolar glands of the urethra, glandulae urethrales, open.
Throughout the urethra there are longitudinal folds that cause its extensibility. The lumen of the urethra at the level of the prostatic and membranous parts appears to be lunate, convex upward, which depends on the ridge and the seminal hillock; throughout the spongy part, in its proximal part, the lumen has the form of a vertical slit, in the distal part - a transverse slit, and in the region of the head - an S-shaped slit.
The lining of the urethra is made up of elastic fibers. A pronounced muscle layer is present only in the prostate and membranous parts; in the spongy part, the mucous membrane is directly fused with spongy tissue, and its smooth muscle fibers belong to the latter. The mucous membrane of the urethra in the prostate has a transitional epithelium, in the membranous - multi-row prismatic, at the beginning of the spongy - single-layer prismatic, and the rest of the length - multi-row prismatic. Innervation: plexus hypogastricus, lumbosacralis. Blood supply: aa.. pudendae interna et extema.
The female urethra, urethra feminina, starts from the bladder with an internal opening, ostium urethrae internum, and is a tube 3–3.5 cm long, slightly curved posteriorly with a bulge and enveloping the lower edge of the pubic symphysis from below and behind. Outside the period of passage of urine through the canal, its anterior and posterior walls are adjacent to one another, but the walls of the canal are characterized by significant extensibility and its lumen can be stretched up to 7–8 mm. The back wall of the canal is closely connected with the anterior wall of the vagina. When exiting the pelvis, the canal pierces the diaphragma urogenitale (see the muscles of the perineum) with its fascia and the sphincter surrounded by arbitrary muscle fibers, i.e. sphincter urethrae. The external opening of the canal, ostium urethrae externum, opens on the eve of the vagina in front of and above the opening of the vagina and is a bottleneck of the canal. The wall of the female urethra consists of membranes: muscular, submucosal and mucous membranes. In the loose tela submucosa, penetrating also into the tunica muscularis, there is a choroid plexus, which gives the tissue a cavernous appearance on the cut. The mucous membrane, tunica mucosa, lies in longitudinal folds. Numerous mucous glands, glandulae urethrales, open into the canal, especially in the lower parts.
The female urethra receives arteries from a. vesicalis inferior and a. pudenda interna. The veins flow through the venous plexus, plexus venosus vesicalis, into v. iliaca interna. Lymphatic vessels from the upper sections of the canal go to nodi lymphatici iliaci, from the lower ones - to nodi lymphatici inguinales.
Innervation from plexus hypogastrics inferior, nn. splanchnici
