Ministry of Health of the Republic of Uzbekistan educational and methodological office for higher and secondary medical education Tashkent Medical Academy Department of Human Anatomy and Ohta. Reticulospinal tract Tecticular spinal tract
1) Bone as an organ, its development, structure, growth. Classification of bones. Osteon.
Each bone,os, is an independent organ and consists of bone tissue. The outside of the bone is covered periosteum, periosteum, inside her bone marrow cavities, cavitas medullares, there is bone marrow. Bones vary in size and shape and occupy specific positions in the body. For ease of study, the following groups of bones are distinguished: long (tubular), short (spongy), flat (wide), abnormal (mixed), air-bearing (Fig. 15).
Long(tubular) bone,os longum has an elongated, cylindrical or triangular middle part - the body of the bone, the diaphysis, diaphysis(from Greek dia - between, phyo - growing). Its thickened ends are called epiphyses, epiphysis(from Greek epi - above). Each epiphysis has an articular surface, fades articuldris, covered with articular cartilage, which serves to connect to neighboring bones. The area of bone where the diaphysis meets the epiphysis is identified as the metaphysis. metaphysics This area corresponds to the epiphyseal cartilage ossified in postnatal ontogenesis. Tubular bones make up the skeleton of the limbs and act as levers. There are long bones (humerus, femur, bones of the forearm and tibia) and short bones (metacarpals, metatarsals, phalanges of the fingers).
Short(spongy) bone,os breve, has the shape of an irregular cube or polyhedron. Such bones are located in areas of the skeleton where bone strength is combined with mobility - in the joints between bones (carpal bones, tarsus bones).
Flat(wide) bones,ossa plana, participate in the formation of body cavities and also perform a protective function (bones of the skull roof, pelvic bones, sternum, ribs). At the same time, they provide extensive surfaces for muscle attachment.
Abnormal(mixed) bones,ossa irregularia They are built complexly, their shape is varied. For example, the vertebral body in shape (and structure) belongs to spongy bones, the arch and processes are flat.
air bones,ossa pneumatica, have a cavity in the body lined with mucous membrane and filled with air. These include some bones of the skull: frontal, sphenoid, ethmoid, upper jaw.
OSTEON (from the Greek osteon - bone) (Haversian system) is a structural unit of the compact substance of bones in vertebrates and humans. The osteon consists of bony plates arranged concentrically around the Haversian canals, giving the bone exceptional strength.
2) Language development, structure, functions, its blood supply, innervation. Regional lymph nodes.
Filiform and cone-shaped papillae, papillae filiformes et papillae conicae, the most numerous, located over the entire surface of the dorsum of the tongue anterior to the border sulcus.
Fungiform papillae, papillae fungiformes, are localized mainly at the apex and along the edges of the tongue. The papillae contain taste buds (bulbs), to which the nerves that conduct taste sensitivity approach.
Vital papillae(surrounded by a rampart), papillae vallatae. In the center of the papilla there is an elevation bearing taste buds (bulbs), and around it there is a ridge separated from the central part by a narrow groove.
Leaf-shaped papillae, papillae foliatae, in the form of flat elongated plates located on the edges of the tongue.
superior longitudinal muscle,i.e. longitudinalis superior begins in the thickness of the root of the tongue, and in some bundles - from the anterior surface of the epiglottis, small horns of the hyoid bone and ends in the area of the apex of the tongue. Function: shortens the tongue, lifts its tip up.
inferior longitudinal muscle,t. longitudinalis inferior n begins at the root of the tongue and ends at its apex. Function: shortens the tongue, lowers the tip of the tongue.
Transverse muscle of the tonguet. transversus linguae, consists of bundles running transversely from the septum of the tongue in both directions to its edges. The muscle bundles end in the mucous membrane of the right and left edges of the tongue. Function: reduces the transverse dimensions of the tongue, raises the back of the tongue.
Vertical muscle of the tonguet. verticalis linguae, located mainly in the lateral sections of the tongue between the mucous membrane of the back and the lower surface of the tongue. Function: flattens the tongue.
genioglossus muscle,t. genioglossus, starts from the mental spine of the lower jaw. Its fibers run back and up the sides of the septum of the tongue and end in the thickness of the tongue. Function: pulls the tongue forward and down.
Hyoglossus muscle,t. hyoglossus, starts from the greater horn and body of the hyoid bone, goes forward and upward; ends in the lateral parts of the tongue. Function: pulls the tongue back and down.
Styloglossus muscle,t. styloglossus, originates from the styloid process of the temporal bone and the stylohyoid ligament, goes down, forward and medially, enters the thickness of the tongue from the side. Function: pulls the tongue back and up; with unilateral contraction, the tongue pulls to the side.
Vessels and nerves of the tongue. Blood flows to the tongue through the lingual artery (from the external carotid artery). Venous blood flows to the vein of the same name, which flows into the internal jugular vein. Lymphatic vessels from the tongue are directed to the submandibular, mental and lateral deep cervical lymph nodes.
The nerves of the tongue come from various sources. The motor innervation of the tongue muscles is carried out by the hypoglossal nerve (XII pair). Sensitive innervation of the mucous membrane is carried out by the endings of the lingual nerve, glossopharyngeal nerve (IX pair), and laryngeal nerve. Taste innervation is carried out by the glossopharyngeal nerve, the facial nerve through the chorda tympani, the fibers of which are part of the lingual nerve.
The lymph nodes:
Nodi lymphatici submandibulares – submandibular lymph nodes. Nodi lymphatici cervicales laterales profundi - deep cervical (internal jugular),
Nodus lumphaticus jugulodigastricus - jugular-digastric nodes
Nodus lymphaticus juguloomohyoideus – jugular-scapular-hyoid nodes.
3) External carotid artery, its topography, branches and areas, blood supply by them.
External carotid artery, a. carotis externa, is one of the two terminal branches of the common carotid artery. The artery divides into its terminal branches - the superficial temporal and maxillary arteries. On its way, the external carotid artery gives off a number of branches that extend from it in several directions. The anterior group of branches consists of the superior thyroid, lingual and facial arteries. The posterior group includes the sternocleidomastoid, occipital and posterior auricular arteries. The ascending pharyngeal artery is directed medially.
Anterior branches of the external carotid artery:
1. superior thyroid artery,a. thyreoidea superior departs from the external carotid artery at its beginning, divides into front And posterior branch, rr. anterior et posterior. The anterior and posterior branches are distributed in the thyroid gland. The following lateral branches depart from the artery:
1) superior laryngeal artery, a. laryngea superior which supplies blood to the muscles and mucous membrane of the larynx;
2) sublingual branch, g. infrahyoideus; 3) sternocleidomastoid branch, sternocleidomasto-ideus, and 4) cricothyroid branch, cricothyroideus, blood supplying muscles of the same name.
2. lingual artery,a. lingudlis, branches off from the external carotid artery. The artery gives off dorsal branches, rr. dorsales linguae. Its final branch is deep artery of the tongue, a. profunda linguae. Two branches depart from the lingual artery: 1) thin suprahyoid branch, suprahyoideus and 2) hypoglossal artery, a. sublingualis, going to the sublingual gland and adjacent muscles
3. Facial artery,a. facialis, arises from the external carotid artery. The lingual and facial arteries can begin in common lingual-facial trunk, truncus linguofacialis. The artery is adjacent to the submandibular gland, giving it glandular branches, rr. glanduldres.
Branches in the neck depart from the facial artery: 1) ascending palatine artery, a. palatina ascendens, to the soft palate;
2) tonsillar branch, tonsillaris, to the palatine tonsil;
3) submental artery, a. submentalis, to the chin and neck muscles. 4) inferior labial artery, a. labialis inferior, and 5) superior labial artery, a. labialis superior. 6) angular artery, a. apgularis.
Posterior branches of the external carotid artery:
1. Occipital artery,a. occipitdlis, arises from the external carotid artery, branches in the skin of the back of the head to occipital branches, rr. occipitdles. The lateral branches depart from the occipital artery: 1) sternocleidomastoid branches, rr. sternocleidomastoidei, to the muscle of the same name; 2) auricular branch, rr. auriculdris, to the auricle; 3) mastoid branch, mastoideus, to the dura mater of the brain; 4) descending branch, r. disсendens, to the muscles of the back of the neck.
2. Posterior auricular artery,a. auricularis posterior, arises from the external carotid artery. Her auricular branch, gg. auricularis, And occipital branch, g. occipitdlis, They supply blood to the skin of the mastoid region, the auricle and the back of the head. One of the branches of the posterior auricular artery - stylomastoid artery, a. stylomastoidea, gives away posterior tympanic artery, a. tympanica posterior, to the mucous membrane of the tympanic cavity and the cells of the mastoid process.
Medial branch of the external carotid artery - ascending pharyngeal artery,a. pharyngea ascendens. Departing from it: 1) pharyngeal branches, rr. pharyngeales, to the muscles of the pharynx and to the deep muscles of the neck; 2) posterior meningeal artery, a. meningea posterior follows into the cranial cavity through the jugular foramen; 3) inferior tympanic artery, a. tympanica inferior, through the lower opening of the tympanic canaliculus penetrates into the tympanic cavity.
Terminal branches of the external carotid artery:
1. Superficial temporal artery,a. temporalis superficialis, divided by frontal branch, g. frontalis, And parietal branch, g. parietalis, nourishing the epicranial muscle, skin of the forehead and crown. A number of branches depart from the superficial temporal artery: 1) under the zygomatic arch - branches of the parotid gland, rr. parotidei, to the salivary gland of the same name; 2) transverse artery of the face, a. transversa faciei, to facial muscles and skin of the buccal and infraorbital areas; 3) anterior auricular branches, gg. auriculares anteriores, to the auricle and external auditory canal; 4) above the zygomatic arch - zygomatic orbital artery, a. zygo-maticoorbitalis, to the lateral corner of the orbit, supplies blood to the orbicularis oculi muscle; 5) middle temporal artery, a. temporalis media, to the temporalis muscle.
2. maxillary artery,a. maxillaris, splits into its final branches. It has three sections: maxillary, pterygoid and pterygopalatine.
4) Parasympathetic innervation of the pelvic organs.
The SM sacral region is represented by the sacral PS nuclei , located in the lateral intermediate substance of the II-IV sacral segments. The fibers form the pelvic splanchnic nerves, pp. splanchnici pelvini. These nerves reach the intramural or intraorgan nodes of the descending colon, sigmoid and rectum, bladder, internal and external genitalia. Intramural nodes are located in the organ plexuses (rectal, vesical, uterovaginal, prostatic, etc.). Short postganglionic fibers extend from them to the glands of the mucous membranes, smooth muscles, and blood vessels of the cavernous bodies). The pelvic organs receive afferent innervation from neurons of the sacral spinal nodes (only “spinal”), sympathetic innervation from neurons of the superior and inferior hypogastric plexuses.
1) Development of the skull in ontogenesis. Individual, age and gender characteristics of the skull.
Brain section of the skull develops from the mesenchyme surrounding the rapidly growing brain. The mesenchymal cover turns into a connective tissue membrane - the stage of the membranous skull. In the area of the arch, this shell is subsequently replaced by bone. Cartilaginous tissue appears only at the base of the skull, near the anterior section of the notochord, which ends dorsal to the pharynx, posterior to the future pituitary stalk. The areas of cartilage lying next to the notochord are called perichordal (parachordal) cartilages, and in front of the notochord are the prechordal plates and cranial crossbars. Subsequently, the cartilage at the base of the skull is replaced by bone, with the exception of small areas (synchondrosis), which persist in adults until a certain age.
Thus, in humans, the vault (roof) of the skull goes through two stages in its development: membranous (connective tissue) and bone, and the base of the skull goes through three stages: membranous, cartilaginous and bone.
Facial part of the skull develops from the mesenchyme adjacent to the initial part of the primary intestine.
Features of the skull. To individually characterize the shape of the skull (cerebral region), it is customary to determine the following dimensions (diameters): longitudinal, transverse, height. The ratio of the longitudinal size (diameter) to the transverse one, multiplied by 100, is the cranial index (longitudinal-latitudinal index). When the cranial index value is up to 74.9, the skull is called long (dolichocrania); an index equal to 75.0-79.9 characterizes the average size of the skull (mesocrania), and with an index of 80 or more, the skull will be wide and short (brachycrania). The shape of the head matches the shape of the skull. In this regard, long-headed people (dolichocephalic), medium-headed (mesocephalic) and broad-headed (brachycephalic) are distinguished.
Looking at the skull from above (vertical norm), one can note the variety of its shapes: ellipsoidal (with dolichocrania), ovoid (with mesocrania), spheroid (with brachycrania), etc.
Sex differences Human skulls are small, so it is sometimes difficult to distinguish a male skull from a female one. At the same time, it is necessary to point out the following not always clearly defined sexual differences in the skull. In the male skull, the tuberosities (places of muscle attachment) are usually better visible; The occipital protuberance and brow ridges protrude more prominently. The eye sockets are relatively large, the paranasal sinuses are more pronounced. The bones are usually somewhat thicker than those of a female skull. The longitudinal (antero-posterior) and vertical dimensions of the male skull are large. The male skull is more capacious (by 150-200 cm3) than the female one: the capacity of the skull in men is on average 1450 cm3, and in women - 1300 cm3. The difference can be explained by smaller body sizes in women.
2) Pleura, its sections, boundaries; pleural cavity, pleural sinuses.
Pleura , pleura, being the serous membrane of the lung, it is divided into visceral (pulmonary) and parietal (parietal). Each lung is covered with pleura (pulmonary), which along the surface of the root passes into the parietal pleura.
Visceral (pulmonary) pleura,pleura visceralis (pulmonalls). Forms downward from the root of the lung pulmonary ligament,lig. pulmonary
Parietal (parietal) pleura,pleura parietalis, in each half of the chest cavity it forms a closed sac containing the right or left lung, covered with visceral pleura. Based on the position of the parts of the parietal pleura, it is divided into the costal, mediastinal and diaphragmatic pleura. Costal pleura, pleura costalis, covers the inner surface of the ribs and intercostal spaces and lies directly on the intrathoracic fascia. Mediastinal pleura, pleura mediastindlis, adjacent to the mediastinal organs on the lateral side, fused with the pericardium on the right and left; on the right it also borders with the superior vena cava and azygos vein, with the esophagus, on the left with the thoracic aorta.
Above, at the level of the superior aperture of the chest, the costal and mediastinal pleura pass into each other and form dome of pleura,cupula pleurae bounded on the lateral side by the scalene muscles. The subclavian artery and vein are adjacent to the dome of the pleura anteriorly and medially. Above the dome of the pleura is the brachial plexus. Diaphragmatic pleura, pleura diaphragmatica, covers the muscular and tendon parts of the diaphragm, with the exception of its central sections. Between the parietal and visceral pleura there is pleural cavity,cavitas pleuralis.
Sinuses of the pleura. In the places where the costal pleura transitions into the diaphragmatic and mediastinal pleura, pleural sinuses,recessus pleurdles. These sinuses are the reserve spaces of the right and left pleural cavities.
Between the costal and diaphragmatic pleura there is costophrenic sinus , recessus costodiaphragmaticus. At the junction of the mediastinal pleura and the diaphragmatic pleura there is diaphragmomediastinal sinus , recessus phrenicomediastinalis. A less pronounced sinus (depression) is present at the place where the costal pleura (in its anterior section) transitions into the mediastinal pleura. Here it is formed costomedial sinus , recessus costomediastinalis.
Boundaries of the pleura. On the right is the anterior border of the right and left costal pleura from the dome of the pleura it descends behind the right sternoclavicular joint, then goes behind the manubrium to the middle of its connection with the body and from here descends behind the body of the sternum, located to the left of the midline, to the VI rib, where it goes to the right and passes into the lower border of the pleura. Bottom line The pleura on the right corresponds to the line of transition of the costal pleura into the diaphragmatic pleura.
Left anterior border of the parietal pleura from the dome it goes, just like on the right, behind the sternoclavicular joint (left). Then it is directed behind the manubrium and the body of the sternum down to the level of the cartilage of the IV rib, located closer to the left edge of the sternum; here, deviating laterally and downwards, it crosses the left edge of the sternum and descends near it to the cartilage of the VI rib, where it passes into the lower border of the pleura. Lower border of the costal pleura on the left is located slightly lower than on the right side. In the back, as well as on the right, at the level of the 12th rib it becomes the posterior border. Posterior pleural border corresponds to the posterior line of transition of the costal pleura into the mediastinal pleura.
3) Femoral artery: its topography, branches and areas supplied with blood. Blood supply to the hip joint.
femoral artery,a. femoralis, is a continuation of the external iliac artery. Branches depart from the femoral artery:
1. Superficial epigastric artery,a. epigastrica superficialis, supplies blood to the lower part of the aponeurosis of the external oblique abdominal muscle, subcutaneous tissue and skin.
2. Superficial artery, circumflex ilium,a. circumflexa iliaca superjicialis, runs in a lateral direction parallel to the inguinal ligament to the superior anterior iliac spine, branches in the adjacent muscles and skin.
3. External genital arteries,ah. pudendae externa, exit through the subcutaneous fissure (hiatus saphenus) under the skin of the thigh and directed to the scrotum - anterior scrotal branches, rr. scrotdles anteriores, in men or to the labia majora - anterior labial branches, rr. labidles anteriores, among women.
4. Deep artery hips, a. profunda femoris, supplies blood to the thigh. The medial and lateral arteries depart from the deep femoral artery.
1) Medial circumflex femoral artery, a. circumflexa femoris medialis, gives away ascending and deep branches, rr. ascendens et profundus, to iliopsoas, pectineus, obturator externus, piriformis and quadratus femoris muscles. The medial circumflex femoral artery sends acetabular branch, g. acetabuldris, to the hip joint.
2) Lateral artery, circumflex femoral bone, a. circumflexa femoris latertis, his ascending branch, Mr. ascendens, supplies the gluteus maximus muscle and the tensor fascia lata muscle. Descending and transverse branches, rr. descendens et transversus, supply blood to the thigh muscles (sartorius and quadriceps).
3) Perforating arteries, aa. perfordntes(first, second and third), supply blood to the biceps, semitendinosus and semimembranosus muscles.
5. Descending genicular artery, a. genus descendens, departs from the femoral artery in the adductor canal, takes part in the formation knee joint network, rete articuldre genus.
4) Medulla. Position of nuclei and pathways in the medulla oblongata.
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The body of the first neuron is the giant pyramidal cell of Betz of the anterior central gyrus cortex. Through the internal capsule, the axons go to the bodies of the second neurons - the cells of the motor nuclei of the cranial nerves.
Starting from the midbrain and further, in the pons and in the medulla oblongata, the fibers of the corticonuclear tract pass to the opposite side to the motor nuclei of the cranial nerves: to the nuclei of pairs III and IV - in the midbrain; to the nuclei of V, VI, VII pairs - in the bridge; to nuclei IX, X, XI, XII pairs - in the medulla oblongata.
Rice. 38. Pyramidal tracts (anterior and lateral corticospinal tracts) ( ABOUT . Feitz , 2009).
III– alpha motor neurons of the anterior horns of the spinal cord
Their axons, as part of the cranial nerves, go to the muscles of the head and neck (Fig. 39).
Rice. 39. Pyramidal tracts (cortical-nuclear tracts)
(O. Feitz, 2009).
I– giant pyramidal cells of Betz;II– nuclei of cranial nerves (III- XIIa couple).
Extrapyramidal tracts
Extrapyramidal tracts conduct impulses to muscles from the basal ganglia, thalamus optic, red nucleus, substantia nigra, olive nucleus, vestibular nerve, reticular formation. The extrapyramidal system automatically maintains skeletal muscle tone.
Extrapyramidal pathways include:
– red nuclear spinal tract (tractus rubrospinalis);
– vestibulospinal tract (tractus vestibulospinalis);
– reticulospinal tract (tractus reticulospinalis);
– tectospinal tract (tractus tectospinalis);
Red nuclear spinal tract (Monakova)
The red nucleus-spinal tracts originate from the red nucleus, pass to the opposite side (Trout decussation), pass in the tegmentum of the bridge, in the lateral sections of the medulla oblongata and descend as part of the lateral cord of the spinal cord to the motor neurons of the spinal cord.
Their axons leave the spinal cord in the anterior roots and are directed as part of the spinal nerves to the skeletal muscles (Fig. 40).
Rice. 40. Extrapyramidal tracts
(Rednuclear spinal tract (Monakova) (O. Feitz, 2009)
I– red nucleus of the midbrain;II- anterior horns of the spinal cord.
vestibulospinal tract
The vestibulospinal tract is important in coordinating the motor functions of the body. It connects the nuclei of the vestibular nerves with the motor neurons of the anterior horns of the spinal cord and is involved in controlling the body’s adjustment reactions when balance is disturbed. Axons of neurons of the lateral vestibular nucleus (Deiters nucleus), as well as the inferior vestibular nucleus (descending root) of the vestibulocochlear nerve, take part in the formation of the vestibular tract.
These fibers descend as part of the anterior funiculus of the spinal cord and end on the motor neurons of the anterior horns of the spinal cord. The nuclei forming the vestibulospinal tract are in direct communication with the cerebellum, as well as with the medial longitudinal fasciculus, which is connected with the nuclei of the oculomotor nerves. The presence of such a connection makes it possible to maintain the direction of the visual axis when turning the head and neck (Fig. 41).
The tectospinal tract, tractus tectospinalis, is a descending motor tract belonging to the extrapyramidal system. It carries out unconditional reflex motor reactions in response to sudden strong visual, auditory, tactile and olfactory stimulation. The first neurons of the tegmental spinal tract are located in the superior colliculus of the midbrain in the subcortical integration center of the midbrain. In this integration center, information comes from the subcortical center of vision (nucleus of the superior colliculus), from the subcortical center of hearing (nucleus of the inferior colliculus), from the subcortical center of smell (nucleus of the papillary body) and collaterals from the conduction pathways of general sensitivity (lemniscus spinalis, lemniscus medialis, lemniscus trigeminalis).
The axons of the first neurons are directed ventrally and upward, bypass the central gray matter of the midbrain and pass to the opposite side. The intersection of the fibers of the tegmental spinal tract with the tract of the same name on the opposite side is called the dorsal decussation of the tegmentum, decussatio tegmenti dorsalis. This chiasm is also called the fountain-shaped chiasm, or the chiasm of Meynert, which reflects the nature of the course of the nerve fibers. The tract then passes in the dorsal part of the pons next to the medial longitudinal fasciculus. Along the tract in the brain stem there are
fibers that end on motor neurons of the motor nuclei
cranial nerves. These fibers are united under the name of the tectonuclear bundle, fasciculus tectonuclearis. They provide protective reactions involving the muscles of the head and neck.
In the region of the medulla oblongata, the tectospinal cord
the path approaches the dorsal surface of the pyramids and is directed into the anterior cord of the spinal cord. In the spinal cord it occupies
the most medial part of the anterior funiculus, limiting the anterior
median gap.
The tectospinal tract can be traced throughout the entire spinal cord. Gradually becoming thinner, it gives off segment by segment branches to the alpha small motor neurons of the motor nuclei of the anterior horns of the spinal cord on its side. The axons of motor neurons conduct nerve impulses to the muscles of the trunk and limbs.
When the tegmental spinal tract is damaged, they disappear
starting reflexes, reflexes to sudden sound, auditory,
olfactory and tactile stimulation.
Reticular-spinal tract
The reticular-spinal tract, tractus reticulospinalis - the descending, efferent pathway of the extrapyramidal system - is designed to perform complex reflex acts (respiratory, grasping movements, etc.), requiring the simultaneous participation of many groups of skeletal muscles. Consequently, it plays a coordinating role in these movements. The reticular-spinal tract conducts nerve impulses that have an activating or, conversely, inhibitory effect on the motor neurons of the motor nuclei of the anterior horns of the spinal cord. Except
In addition, this pathway transmits impulses to gamma motor neurons, providing the tone of skeletal muscles.
The first neurons of the reticular spinal tract are located in the reticular formation of the brain stem. The axons of these
neurons go in a descending direction. In the spinal cord they form a bundle, which is located in the anterior cord. The bundle is well defined only in the cervical and upper thoracic regions of the spinal cord. It thins out segment by segment, sending fibers to the gamma motor neurons of the motor nuclei of the anterior horns of the spinal cord. The axons of these neurons project to the skeletal muscles.
vestibulospinal tract
The vestibulospinal tract, tractus vestibulospinalis, is the descending motor pathway of the extrapyramidal system. It provides unconditioned reflex motor acts in case of imbalances in the body. The vestibulospinal tract is formed by the axons of cells of the lateral and inferior vestibular nuclei (Deiters and Roller nuclei). In the medulla oblongata it is located in the dorsal region. In the spinal cord it passes at the border of the lateral and anterior cords, therefore it is penetrated by horizontally oriented fibers of the anterior roots of the spinal nerves.
The fibers of the vestibulospinal tract end segment by segment on the alpha motor neurons of the motor nuclei of the anterior horns of the spinal cord. The axons of motor neurons as part of the spinal nerve roots leave the spinal cord and go to the skeletal muscles.
Olive-spinal tract
Olive-spinal tract, tractus olivospinalis, - descending
motor pathway of the extrapyramidal system It provides unconditional reflex maintenance of neck muscle tone and motor acts aimed at maintaining body balance.
The olivospinal tract begins from the neurons of the inferior olivary nucleus of the medulla oblongata. Being a phylogenetically new formation, the inferior olivary nucleus has direct connections with the cerebral cortex of the frontal lobe (cortico-olive tract, tr. corticoolivaris), with the red nucleus (red nucleus olivary tract, tr. rubroolivaris) and with the cortex of the cerebellar hemispheres (olivo-cerebellar tract, tr olivocerebellatis). The axons of the cells of the inferior olive nucleus are collected in a bundle - the olivo-spinal tract, which passes in the anteromedial section of the lateral cord. It can be traced only at the level of the six upper cervical segments of the spinal cord.
The fibers of the olivospinal tract end segment by segment on the alpha motor neurons of the motor nuclei of the anterior horns of the spinal cord.
brain The axons of motor neurons as part of the spinal nerve roots leave the spinal cord and go to the muscles of the neck.
Medial longitudinal fasciculus
Medial longitudinal fasciculus, fasciculus longitudinalis medialis
is a combination of descending and ascending
fibers that carry out coordinated movements of the eye
“block and heads. This function is necessary to maintain equilibrium
this body. Performing this function becomes possible only
but as a result of the morphofunctional connection between the nerve centers
frames that provide innervation to the muscles of the eyeball (motors)
body nuclei of the III, IV and VI pairs of cranial nerves), centers,
responsible for the innervation of the neck muscles (motor nucleus XI pair
and motor nuclei of the anterior horns of the cervical segments of the spinal
brain), center of balance (Deiters nucleus). The work of these centers is coordinated by the neurons of the large nuclei of the reticular formation -
intermediate nucleus, nucleus interstitialis (Cajal's nucleus), - and the nucleus of the posterior commissure, nucleus commissuraeposterior (Darkshevich's nucleus).
The intermediate nucleus and the nucleus of the posterior commissure of the brain are located
and the rostral part of the midbrain, in its central gray matter. The axons of the neurons of these nuclei form the medial longitudinal fasciculus, which passes under the central gray matter
near the midline. Without changing its position, it continues in the dorsal part of the pons and deviates in the ventral direction in the medulla oblongata. In the spinal cord it is located in
anterior funiculus, in the angle between the medial surface of the anterior
horns and anterior white commissure. The medial longitudinal fasciculus can be traced only at the level of the upper six cervical segments.
Within the midbrain as part of the medial longitudinal fasciculus
fibers come from the posterior longitudinal bundle, which unites
iegetative centers. This connection between the medial and posterior longitudinal fasciculi explains the autonomic reactions that arise
with vestibular loads. From the medial longitudinal fasciculus fibers are directed to the motor nucleus of the oculomotor nerve.
This nucleus has five segments, each of which is responsible for the innervation of certain muscles: neurons of the upper segment
(1st) innervate the muscle that lifts the upper eyelid; 2nd - rectus eye muscle; 3rd - inferior oblique muscle of the eye; 4th - inferior rectus muscle of the eye; 5th - medial rectus muscle of the eye.
Neurons of the 1st, 2nd and 4th segments receive fibers from the medial longitudinal fasciculus on their side, neurons of the 3rd segment - from the opposite side. Neurons of the 5th segment also close to
the central unpaired nucleus (convergence) and are connected with the medial longitudinal fasciculus on their side. They provide the possibility of movement of the eyeball in the medial direction and the simultaneous convergence of the eyeballs (convergence).
Further, within the midbrain, fibers from the medial longitudinal fasciculus are sent to the neurons of the motor nucleus of the trochlear nerve of the opposite side. This nucleus is responsible for the innervation of the superior oblique muscle of the eyeball.
In the bridge, the medial longitudinal fasciculus includes the axons of the cells of the Deiters nucleus (VIII pair - vestibulocochlear nerve),
which go in an ascending direction to the neurons of the intermediate
kernels. Fibers extend from the medial longitudinal fasciculus to neurons
motor nucleus of the abducens nerve (VI pair), responsible for the innervation of the lateral rectus muscle of the eyeball. And finally,
within the medulla oblongata and spinal cord, from the medial longitudinal fasciculus, fibers are directed to the neurons of the motor nucleus
accessory nerve (XI pair) and motor nuclei of the anterior horns
six upper cervical segments, responsible for the work of the neck muscles.
In addition to the general coordination of the muscles of the eyeball and head, the medial longitudinal fasciculus performs an important integrative
role in the activity of the eye muscles. Communicating with nuclear cells
oculomotor and abducens nerves, it ensures the coordinated function of the external and internal rectus muscles of the eye, manifested in a combined rotation of the eyes to the side. In this case, a simultaneous contraction of the external rectus muscle of one eye and the internal rectus muscle of the other eye occurs.
When the intermediate nucleus or medial longitudinal fasciculus is damaged, the coordinated functioning of the muscles of the eyeball is disrupted. Most often this manifests itself in the form of nystagmus (frequent contractions of the muscles of the eyeball, directed in the direction of movement, when the gaze stops). Nystagmus can be horizontal, vertical and even rotatory (rotational). Often these disorders are supplemented by vestibular disorders (dizziness) and autonomic disorders (nausea, vomiting, etc.).
Posterior longitudinal fasciculus
The posterior longitudinal fasciculus, fasciculus longitudinalis dorsalis, is a set of descending and ascending fibers that communicate between the autonomic centers of the brain stem and spinal cord. The posterior longitudinal fasciculus (fasciculus of Schütz) originates from the cells of the posterior nuclei of the hypothalamus. The axons of these cells unite into a bundle only at the border of the diencephalon and midbrain. It then passes in close proximity to the midbrain aqueduct. Already in the midbrain, some of the fibers of the posterior longitudinal fasciculus are directed to the accessory nucleus of the oculomotor nerve. In the area of the bridge, fibers extend from it to the lacrimal and
superior salivary nuclei of the facial nerve. In the medulla oblongata, fibers branch to the inferior salivary
the nucleus of the glossopharyngeal nerve and the dorsal nucleus of the vagus nerve.
In the spinal cord, the posterior longitudinal fasciculus is located in the form of a narrow band in the lateral funiculus, next to the lateral corticospinal tract. The fibers of the Schütz bundle end segment by segment on the neurons of the lateral intermediate nucleus, which are the autonomic sympathetic centers of the spinal cord. Only a small part of the fibers of the dorsal longitudinal fasciculus is isolated at the level of the lumbar segments and is located near the central canal. This bundle is called periependymal. The fibers of this bundle end on the neurons of the sacral parasympathetic nuclei. The axons of the cells of the parasympathetic and sympathetic nuclei leave the brain stem or spinal cord as part of the cranial or spinal nerves and are directed to the internal organs, vessels and glands. So the rear
the longitudinal fasciculus plays a very important integrative role in the regulation
lation of vital body functions.
News about tegnospinal tract
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- Yu. A. Zozulya, Yu. A. Orlov Institute of Neurosurgery named after. A. P. Romodanova AMS of Ukraine, Kiev Congenital malformations are one of the main causes of child mortality and disability. In Ukraine in 2001, almost 400 thousand children were born, of which 48 thousand had deformities. Significant places
Discussion Tectospinal tract
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tectospinal tract) projection descending nerve pathway, starting in the superior colliculi of the roof of the midbrain, passing through and anterior, ending in its anterior horns.
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.
See what “tegnospinal tract” is in other dictionaries:
- (tractus tectospinalis, PNA, BNA, JNA; synonym tectospinal tract) projection descending nerve tract, starting in the superior colliculi of the roof of the midbrain, passing through the brain stem and the anterior cord of the spinal cord, ending in its ... ... Large medical dictionary
Large medical dictionary
- (tractus tectospinalis; anat. tectum mesencephali roof of the midbrain) see tectal spinal tract ... Medical encyclopedia
- (medulla spinalis) part of the central nervous system located in the spinal canal. S. m. has the appearance of a white cord, somewhat flattened from front to back in the area of thickenings and almost round in other sections. In the spinal canal... ... Medical encyclopedia
Spinal cord- (medulla spinalis) (Fig. 254, 258, 260, 275) is a cord of brain tissue located in the spinal canal. Its length in an adult reaches 41-45 cm, and its width is 1-1.5 cm. The upper part of the spinal cord smoothly passes into... ... Atlas of Human Anatomy
Pathways of the nervous system- Conscious sensory pathways are conductors that carry nerve impulses to the cerebral cortex. Depending on the location of the receptors, which determines the nature of the impulses, the pathways are divided into... ... Atlas of Human Anatomy
Diagram of the location of pathways in the white matter and nuclei in the gray matter on a cross section of the spinal cord- thin and wedge-shaped beams; thin and wedge-shaped beams; own (posterior) bundle; posterior spinal cerebellar tract; lateral pyramidal (cortical spinal) tract; own bundle (lateral); red nuclear spinal tract; ... ... Atlas of Human Anatomy
The central nervous system (tractus sistematis nervosi centralis) is a group of nerve fibers that are characterized by common structure and functions and connect various parts of the brain and spinal cord. All nerve fibers of one path begin from... Medical encyclopedia
- (ki) (fasciculus, i, PNA, BNA, JNA) in anatomy, a set of fibers (nerve, connective tissue or muscle), united anatomically and functionally. Arnold's bundle see Frontal bridge path. Atrioventricular bundle (f. atrioventricularis ... Medical encyclopedia
Brain: Midbrain Latin name Mesencephalon Midbrain ... Wikipedia
