Dental Dictionary. Anatomy of the Medial surface of the human hemisphere - information Lateral part

Anatomical terminology serves to accurately describe the location of body parts, organs and other anatomical structures in space and in relation to each other in the anatomy of humans and other animals with a bilateral type of body symmetry, a number of terms are used. Moreover, in human anatomy it has a number of terminological features that are described here and in a separate article.

Terms used

Terms describing position relative to the center of mass and the longitudinal axis of the body or outgrowth of the body:

• Abaxial (antonym: adaxial) - located further from the axis.
• Adaxial (antonym: abaxial) - located closer to the axis.
• Apical(antonym: basal) - located at the top.
• Basal (antonym: apical) - located at the base.
• Distal (antonym: proximal) - distant.
• Lateral (antonym: medial) - lateral, lying further from the median plane.
• Medial (antonym: lateral) - median, located closer to the median plane.
• Proximal (antonym: distal) - close.

Terms describing position relative to major body parts:

• Aboral (antonym: adoral) - located at the opposite pole of the mouth of the body.
• Adoral (antonym: aboral) - located near the mouth.
• Abdominal - abdominal, referring to the abdominal region.
• Ventral (antonym: dorsal) - abdominal (front).
• Dorsal (antonym: ventral) - dorsal (back).
• Caudal (antonym: cranial) - caudal, located closer to the tail or to the rear end of the body.
• Cranial (antonym: caudal) - head, located closer to the head or to the front end of the body.
• Rostral - nasal, literally - located closer to the beak. Located closer to the head or to the front end of the body.

Basic planes and cuts:

• Sagittal - an incision in the plane of bilateral symmetry of the body.
• Parasagittal - an incision running parallel to the plane of bilateral symmetry of the body.
• Frontal - an incision running along the anteroposterior axis of the body perpendicular to the sagittal one.
• Axial - an incision in the transverse plane of the body

Directions

In animals, there is usually a head at one end of the body, and a tail at the opposite end. The head end in anatomy is called cranial, cranialis (cranium - skull), and the tail is called caudal, caudalis (cauda - tail). On the head itself, they are guided by the nose of the animal, and the direction to its tip is called rostral, rostralis (rostrum - beak, nose).

The surface or side of the animal's body directed upwards, against gravity, is called dorsal, dorsalis (dordum - back), and the opposite side of the body, which is closest to the ground, when the animal is in its natural position, that is, it walks, flies or swims - ventral, ventralis (venter - belly). For example, a dolphin's dorsal fin is located dorsally, and the udder of the cow on ventral side.

For limbs, the concepts are true: proximal, proximalis, - for a point less distant from the body, and distal, distalis, - for a remote point. The same terms for internal organs mean remoteness from the place of origin of this organ (for example: “distal segment of the jejunum”).

Right, dexterand left, sinister, the sides are designated as they could be presented from the point of view of the studied animal. Term homolateral, less often ipsilateral indicates location on the same side and contralateral - located on the opposite side. Bilaterally - means location on both sides.

Application in human anatomy

All descriptions in human anatomy are based on the belief that the body is in the position of the anatomical stance, that is, the person is standing straight, arms are down, palms are facing forward.

Areas closer to the head are called upper; farther - lower... Upper, superior, corresponds to the concept cranial, and the bottom, inferior, - the concept caudal. Front, anteriorand rear, posterior, correspond to the concepts ventral and dorsal... Moreover, the terms front and rear in relation to four-legged animals are incorrect, the concepts should be used ventral and dorsal.

Direction designation

Formations lying closer to the median plane - medial, medialis, and located further - lateral, lateralis... Formations located on the median plane are called median, medianus... For example, the cheek is located lateral wings of the nose, and the tip of the nose - median structure. If an organ lies between two adjacent formations, it is called intermediate, intermedius.

Formations located closer to the body will proximal in relation to more distant, distal... These concepts are also valid when describing organs. For example, distal the end of the ureter enters the bladder.

Central - located in the center of the body or anatomical region;
peripheral - external, remote from the center.

When describing the position of organs lying at different depths, the following terms are used: deep, profundusand surface, superficialis.

Concepts outer, externusand interior, internusare used to describe the position of structures in relation to various body cavities.

The term visceral, visceralis (viscerus - the inside) denote belonging and close location with any organ. AND parietal, parietalis (paries - wall) - means related to any wall. For example, visceral pleura covers the lungs, while parietal the pleura covers the inner surface of the chest wall.

Marking directions on the limbs

The surface of the upper limb relative to the palm is designated by the term palmaris - palmar, and the lower limb relative to the sole - plantaris - plantar.

Questions and answers for the discipline exam

Human anatomy and physiology

Specialty:

Nursing 060501 (evening department)

Ticket number 1.

1. Tissues, organs, organ systems, the body as a whole.

2. Terminal brain: structure. Cerebral hemispheres. Surfaces, lobes. Furrows, convolutions. Limbic system.

"Basics of Histology - Tissue".

Tissues are a group of cells and intercellular substance that have the same structure and perform the same function.

Kinds:

1.epithelial

2.blood and lymph

3.connecting

4.muscular

5. nervous

Organ (ancient Greek. ὄργανον - "instrument") - a separate set of different types of cells and tissues that perform a specific function in a living organism.

An organ is a functional unit within an organism, separate from other functional units of a given organism. The organs of one organism are interconnected in their functions in such a way that the organism is a set of organs, which are often combined into various organ systems.

An organ is called only that set of tissues and cells, which has a stable position within the organism and whose development is traced within ontogenesis (organogenesis).

Organ system - a group of organs similar in origin, structure and functions performed. The organs are located in cavities filled with fluid. They communicate with the external environment. The set of anatomical terms that determine the position of organs in the body and their direction is anatomical nomenclature.

Person - biosocial creature. Organism - a biological system, endowed with intelligence. The laws of life (self-renewal, self-reproduction, self-regulation) are inherent in man. These patterns are realized with the help of the processes of metabolism and energy, irritability, heredity and homeostasis - the relatively dynamic constancy of the internal environment of the body. The human body is multilevel:

Molecular

Cellular

Tissue

Organ

Systemic

The relationship in the body is achieved through nervous and humoral regulation. A person constantly has new needs. Ways to satisfy them: self-satisfaction or with outside help.

Self-gratification mechanisms:

Congenital (changes in metabolism, work of internal organs)

Acquired (conscious behavior, mental reactions)

Needs satisfaction structures:

1.executive (respiratory, digestive, excretory)

2.regulatory (nervous and endocrine)

Answer 2

The large brain or telencephalon (telencephalon) - develops from the anterior cerebral bladder. It develops later than other departments, but in humans it reaches the highest development. In terms of mass and size, it surpasses other departments. The brain consists of 2 hemispheres (left and right), separated by a longitudinal slit and connected in the depth of this slit by means of the corpus callosum, anterior and posterior adhesions and adhesions of the fornix. Between the hemisphere and the cerebellum, a transverse slit runs behind. Inside the cerebral hemispheres there are cavities filled with cerebrospinal fluid - 1 and 2 lateral ventricles. The first is the left ventricle, 2 - the right. Each ventricle has: a central part and 3 horns (anterior - frontal, posterior - occipital, lower - temporal). In the central part and the temporal horn, there are vascular plexuses that secrete cerebrospinal fluid. The interventricular openings communicate with the 3 ventricles with two lateral ones; Monroe's hole communicates the lateral ventricles with 3; two lateral apertures (Lushka's openings) communicate the 4th ventricle with the subarachnoid space; the medial aperture (Magendie's opening) communicates the 4th ventricle with the cerebellar - cerebral cistern - expansion of the subarachnoid space.

Each hemisphere is covered on the outside with a bark (cloak) - a gray matter, consisting of neurons, inside contains a white matter - processes of neurons. Inside the white matter there are clusters of gray - the basal nuclei. The thalamus and brain stems communicate with the hemispheres. The border between the cerebrum and the diencephalon lies where the inner capsule is adjacent to the lateral walls of the thalamus. Each hemisphere has 3 surfaces:

Upper lateral (convex)

Medial - flat

Bottom - uneven

The most protruding forward and backward sections of the hemispheres are the poles:

Occipital

Temporal

The surface of the hemispheres is dotted with convolutions and grooves. A gyrus is a cushion of medulla that rises above the surface of the hemisphere. A groove is a depression between the convolutions. The presence of grooves and convolutions increases the surface of the BM without increasing its volume. Distinguish between primary gyrus (all the same) and secondary (individual, depending on the level of intelligence).

There are 5 lobes in each hemisphere:

Parietal

Temporal

Occipital

Insular

The frontal lobe occupies the anterior cranial cavity and is located in the anterior cranial fossa. This lobe is delimited from the parietal central (Roland) sulcus. The parietal lobe is located behind the central sulcus. The temporal lobe is located in the middle cranial fossa and is separated from the frontal and parietal lobes by the lateral (Sylvian) groove. The occipital lobe is located in the posterior part of the skull above the cerebellum and is separated from the parietal lobe by the parietal-occipital groove located on the medial surface of the hemisphere. The islet is located deep in the lateral groove. It can be seen when the frontal, parietal and temporal lobes are moved apart or removed. The medial surface of the hemisphere has 2 convolutions - the cingulate (above the corpus callosum). From the back downwards, it narrows, forming an isthmus of the cingulate gyrus. It passes into the second, wider gyrus of the hippocampus (parahippocampal) - the gyrus of the sea horse (bent in the form of a comma).

From above it is limited by the groove of the hippocampus. The cingulate, isthmus and parahippocampal gyrus form a vaulted gyrus, which belongs to the limbic system. The anterior curved end of the hippocampal gyrus is a hook. The posterior end of the gyrus has a thickening - the amygdala. This gyrus separates the temporal lobe from the brainstem.

KBM is the highest department of the central nervous system, which forms the activity of the body as a whole in its interaction with the environment. This is the youngest brain formation. With its appearance, corticolization of functions occurs - the regulation of body functions passes from the underlying departments into the cortex. She begins to regulate and control all processes and activities in general. The bark is the steward of all body functions, it is a receptacle of intelligence, a workshop for our desires, thoughts, will and feelings (I.P. Pavlov). the work of the CBM together with the basal nuclei form the GNI.

KBM is a 5 mm thick layer of gray matter. Due to the folds, its area is 0.25 m2. it contains up to 17 billion neurons, which are grouped into layers and forms the neocortex - the new cortex - the highest integration division of the somatic nervous system. In humans, the neocortex occupies 95.6% of the entire surface of the cortex. The six-layered type of bark is modified in different areas. The fifth layer of the neocortex is formed by Betz pyramidal cells, from which the pyramidal system begins. The rest is occupied by the paleocortex - the old crust. This structure is 3-layer. The processes taking place in the paleocortex are not always reflected in consciousness. It includes the most ancient parts of the cortex, which are part of the limbic system (olfactory brain).

KBM layers:

1.the outer molecular layer - few nerve cells

2.Outer granular layer - granular neurons - rounded, multipolar

3.pyramidal layer - pyramidal neurons

4.inner granular layer - small round or stellate neurons - afferent

5.inner pyramidal layer - large pyramidal neurons - Betz cells - efferent neurons

6..7 multimorphic layers - fusiform neurons - insertion

The space between the cortex and the basal nuclei is occupied by white matter - these are the processes of neurons that form nerve fibers and pathways of the large brain:

Associative (short and long) - connection between parts of the same hemisphere

· Commissural (connection of identical symmetrical sections of different hemispheres) - the corpus callosum - the largest commissure of the brain.

· Projection (conducting) - communication with other parts of the brain to the spinal cord. They are long, conduct excitation centripetally (to the cortex) and centrifugally (from the cortex).

Lateral surface of the hemisphere:

1.precentral sulcus

2.precentral gyrus

3.roland furrow

4.postcentral sulcus

5.postcentral gyrus

6.upper parietal lobe

7.inferior parietal lobe

8.Angular gyrus

9.upper, middle and lower temporal gyri

10.medium and inferior temporal sulci

11.sylvian furrow

12.inferior frontal sulcus

13.inferior frontal gyrus

14.medial frontal gyrus

15.upper frontal sulcus

16.upper frontal gyrus

The medial surface of the hemisphere.

1.corpus callosum: trunk, knee, beak

2.anterior brain commissure

3.the posterior commissure of the brain

4.vault of the brain

5.sulcus of the corpus callosum

6.cingular gyrus

7.Lingual groove

8.upper frontal gyrus

9.paracentral lobule

10.pre-wedge

11.parieto-occipital sulcus

13. furrow groove

14.Lingual gyrus

15.sulcus of the hippocampus

16.parahippocampal gyrus

These grooves and convolutions are primary, secondary and tertiary for each person.

Lecture

FINAL BRAIN STRUCTURE

The telencephalon is the largest part of the central nervous system, much larger in volume than the stem part of the brain, which it covers. In the formations of the telencephalon, centers are concentrated that control the activity of various parts of the brain stem and spinal cord. The cerebral cortex carries out higher nervous activity and determines the behavior of the body, depending on the constantly changing conditions of the external environment.

The telencephalon consists of two hemispheres, connected by a commissure - the corpus callosum. Between the hemispheres is a deep longitudinal slit of the cerebrum, between the posterior hemispheres and the cerebellum is the transverse slit of the cerebrum. Each hemisphere consists of three surfaces: the upper-lateral (upper-lateral) - spherical, medial - flat, lower - irregular, and three poles: frontal, occipital and temporal.

In each hemisphere I distinguish: a cloak (mantle) covered with bark, subcortical (basal) ganglia and the olfactory brain. The lateral ventricles are the endbrain cavity.

The structure of the cloak or mantle. The entire surface of the mantle is covered with crust and is divided by deep permanent primary grooves: central, lateral (lateral), and parieto-occipital. These grooves divide each hemisphere into five lobes - frontal, parietal, temporal, occipital and Reil's islet, located deep in the lateral groove. Each lobe is divided by permanent secondary grooves into permanent convolutions, and shallow, unstable and changeable tertiary grooves limit such convolutions.

Upper-lateral surface of the hemisphere.

The frontal lobe is located in front of the central sulcus. (Roland's furrow). It distinguishes between the precentral groove, which lies parallel to and in front of the central groove, the superior and inferior frontal grooves located in the anteroposterior direction from the central one. Between the grooves are the precentral, superior, middle and inferior frontal gyri.

Parietal lobe.

Located behind the central sulcus. It has a postcentral groove running behind and parallel to the central groove, between them lies the postcentral gyrus. The intra-parietal sulcus departs from the postcentral sulcus perpendicularly and divides the parietal lobe into the superior and inferior parietal lobes. In the inferior parietal lobe, the supra-marginal gyrus, which lies at the end of the lateral sulcus, and the angular gyrus, which lies at the end of the superior temporal sulcus, are distinguished.

The temporal lobe.

Lies below the lateral groove and is divided by the superior and inferior temporal grooves into the superior, middle and inferior temporal gyri. The inferior temporal gyrus is bounded from below by the occipital-temporal groove, which lies on the border of the superior-lateral and inferior surfaces of the temporal lobe.

Occipital lobe

Located behind the parietal-occipital sulcus and has very inconsistent grooves and convolutions running transversely and longitudinally

The islet has the shape of a triangle, surrounded by a circular groove of the islet, its surface is covered with short convolutions, diverging fan-shaped.

Medial surface

A groove of the corpus callosum passes above the corpus callosum, above it, maintaining the same direction, there is a cingulate groove, between them is the cingulate gyrus, the narrowed place of which is the isthmus, continues into the parahippocampal gyrus, at its anterior end, a posterior bend is formed - a hook. The parahippocampal gyrus is limited from the inner side by the sulcus of the hippocampus, and from the outer side by the collateral sulcus. Inside the groove of the hippocampus is the dentate gyrus, which is a serrated gray strip. The direct continuation of the cingulate groove is the sub-parietal groove. On the medial surface, the parieto-occipital groove is clearly visible, from the lower end of which the spur groove extends upward at an angle. The part of the brain between these grooves is called a wedge, and the part of the brain lying in front of the parietal-occipital groove is called the pre-wedge, bounded from below by the sub-parietal groove, and in front is the paracentral lobule, which in turn borders on the medial part of the superior frontal gyrus.

Bottom surface.

It is represented by the frontal, temporal and occipital lobes of the brain.

On the frontal lobe, there is an olfactory groove running parallel to the longitudinal interhemispheric fissure and covered by the olfactory bulb, the olfactory tract and the olfactory triangle - the peripheral parts of the olfactory brain. A straight gyrus lies between the longitudinal fissure and the olfactory groove. The rest of the surface of the lower part of the frontal lobe is occupied by the orbital grooves and convolutions.

The area of \u200b\u200bthe lower surface located behind the lateral sulcus belongs to the temporal and occipital lobes, where the occipital-temporal sulcus passes, and inside it is the collateral sulcus and the sulcus of the hippocampus. Between the occipitotemporal and collateral grooves lies the lateral occipitotemporal gyrus (circumferential), inside of the collateral groove is the medial occipitotemporal gyrus, it is limited by the collateral and grooves, between the collateral and hippocampal grooves - the parahippocampal gyrus ends. The parahippocampal and cingulate gyrus make up the vaulted gyrus. The lateral and medial occipital-temporal gyrus are connected by transitional gyri to the parahippocampal gyrus.

The structure of the cortex.

The surface of the hemispheres, both in the depth of the furrows and at the apex of the convolutions, is covered with a significant layer of gray matter, which is called telencephalon... On average, the thickness of the cortex in an adult is 2.5-3 mm (1.3-4.5 mm), and the surface is 145-220 thousand mm 2, of which 1/3 or 72 thousand mm 2 is the free surface , 2/3 or 148 thousand mm 2 is located in the depth of the furrows. Distinguish old, old and new bark.

TO ancient crust refer to bony tubercle, anterior perforated substancerelated to the structures of the olfactory brain, podmozolic gyrus, semilunar gyrussurrounding the amygdala and lateral olfactory gyrus... The ancient crust is characterized by the absence of a layered structure. It is dominated by large neurons, grouped into cell islets.

To the old barkinclude hippocampus and dentate gyrus, in the area of \u200b\u200bthe knob it comes out to the surface. The old cortex has three cell layers: molecular layer from the apical dendrites of the pyramidal cells of the hippocampus, radial- from pyramidal cells and layer of polymorphic cells. The key structure of the old bark is hippocampus or ammonium horn, located mediobasally deep in the temporal lobes. It has a peculiar curved shape (hippocampus in translation - seahorse) and almost throughout its entire length forms an invagination into the cavity of the lower horn of the lateral ventricle, the wall of which is bordered by a layer of white matter of the hippocampus. The hippocampus is actually a fold (gyrus) of the old cortex. Spliced \u200b\u200bwith her and wrapped over her dentate gyrus. The hippocampus has extensive connections with many other structures in the brain. It is the central structure of the limbic system in the brain.

The ancient and old cortex are associated with the olfactory function, the most ancient function of the telencephalon.

New barkis the rest of 95.6% of the total area. The bark contains about 40 mlr. neurons ,. Neurons have different shapes - pyramidal, spindle-shaped, star-shaped, arachnid and so on. The cells of the cortex, together with the processes, form from 6 to 9 layers, but since in the fetus at the end of intrauterine development, almost all parts of the cortex have six layers, the initial type is the six-layer bark. In some areas, the number of layers varies, so there are nine in the occipital lobe, and five in the olfactory lobe. Basically, the following layers are distinguished:

I- light coloured (molecular), about 0.2 mm thick, consisting of apical dendrites and axons rising from the cells of the lower layers that are in contact with each other and a small number of small horizontal grain cells.

II - outer granular, the thickness of which is 0.1 mm. It consists of densely spaced small neurons of stellate and pyramidal shapes, the axons of which end on neurons III, V, VI layers.

III- outer pyramidal thickness of about 1 mm, consists of small pyramidal neurons, variously located in an upright position. A typical pyramidal neuron has the shape of a triangle with the apex pointing up. An apical dendrite branches off from the apex, branching in the overlying layers. The axon of the pyramidal cell departs from the base of the cell and goes down. The dendrites of the cells of the III layer are directed to the II layer. The axons of the cells of the III layer end on the cells of the underlying layers or form associative fibers.

IV - inner granular layer, consisting of densely spaced small stellate neurons with short processes and small pyramids.

The dendrites of cells in layer IV extend into the molecular layer of the cortex, and their collaterals branch out in their layer. The axons of the cells of the IV layer can rise into the overlying layers or go into the white matter as associative fibers. The thickness of the IV layer is from 0.12 to 0.3 mm. The inner granular layer is most developed in the visual zone and is almost absent in the motor zone.

V- deep layer of pyramidal cells represented by large pyramidal neurons (Betz cells), especially developed in the motor zone - the anterior central gyrus. Their apical dendrites reach the molecular layer, while the basal dendrites are distributed in their layer. Axons of V layer cells leave the cortex and are associative, commissural or projection fibers. The thickness of the V layer reaches 0.5 mm.

VI - polymorphic layer of multiforme neurons contains cells of various shapes (triangular, fusiform) and sizes, has a thickness of 0.1 to 0.9 mm. Part of the dendrites of the cells of this layer reaches the molecular layer, while others remain within the IV and V layers. The axons of layer VI cells can rise to the upper layers or leave the cortex as short or long associative fibers.

VII layer - fusiform layer distinguish only in some areas of the cortex.

Cells in one layer of the cortex perform a similar function in processing information.

Layers I and IV are the site of branching of associative and commissural fibers, that is, they receive information from other cortical structures.

Layers III and IV are input, afferent for the projection fields, since it is in these layers that the thalamic fibers end.

Layer V of cells performs an efferent function, its axons carry information to the underlying structures of the brain.

Layer VI is also output, but its axons do not leave the cortex and are associative.

The basic principle of the functional organization of the cortex is the combination of neurons into columns. The column is located perpendicular to the surface of the cortex and covers all its layers from the surface to the white matter. Links between cells of one column are carried out vertically along the column axis. The lateral processes of the cells are short. The connection between the columns of adjacent zones is carried out through fibers extending into the depths, and then entering another zone - associative fibers. The functional organization of the cortex in the form of columns is found in the somatosensory, visual, motor, and associative cortex.

Separate zones of the cortex have fundamentally the same cellular structure, however, there are differences, especially in the structure of layers III, IV and V, which can disintegrate into several sublayers. In addition, essential cytoarchitectonic features are the density and size of cells, the presence of specific types of neurons, the location and direction of the course of myelin fibers.

Morphological differences in the distribution of cells in the layers of the cerebral cortex coincide with the different functional properties of one or another of its fields, which is the basis for the theory of the distribution (localization) in the cerebral cortex of functionally different cell centers.

Architectonics of the cerebral cortexshows that different areas of the cortex are not the same in terms of their functional significance. The doctrine of the architectonics of the cortex was first described by the Kiev anatomist, professor V.A. Betz (1874), who identified 8 characteristic fields in the human cortex. This discovery by V.A. Betz was subsequently developed in Russia and abroad and now constitutes the most important branch of neurology - cytoarchitectonics and myeloarchitectonics of the brain.

Based on similar structural features (size and shape of cells, distribution of nerve fibers), Brodmann combined the 52 fields previously identified in the cerebral cortex into 11 regions that do not coincide with its anatomical division into lobes. They are allocated:

frontal area - fields 8, 9, 10, 11, 12, 44, 45, 46 and 47;

precentral - fields 4 and 6;

behind the central- fields 1,2,3 and 43;

insular- fields 13, 14, 15 and 16;

parietal - fields 5, 7, 39 and 40;

temporal- fields 20, 21, 22, 36, 37, 38, 41, 42 and 52;

occipital- fields 17, 18 and 19;

waist- fields 23, 24, 25, 31, 32 and 33;

the area behind the shaft of the corpus callosum - fields 26, 29 and 30;

olfactory and gyrus region of the seahorse- fields 27, 28, 34, 35 and 48.

The modern study of the cyto- and myeloarchitectonics of the cerebral cortex has provided grounds for identifying more than 250 fields. These fields are combined into the following cytoarchitectonic areas: occipital, inferior parietal, superior parietal, postcentral, precentral, frontal, temporal, insular and limbic... But this, presumably, does not exhaust the possibility of isolating new fields in the process of studying the structure of the brain.

Cortical ends (centers) of the analyzers. The doctrine of the cytoarchitectonics of the cerebral cortex corresponds to the doctrine of I.P. Pavlova about the cortex as a system of cortical ends of analyzers. The analyzer, according to Pavlov, "is a complex nervous mechanism that begins with the external perceiving apparatus and ends in the brain." ) in the cerebral cortex of the telencephalon. According to Pavlov, the cortical end of the analyzer consists of a "core" and "scattered elements."

According to its structural and functional features, the core of the analyzer is subdivided into the central field of the nuclear zone and the peripheral one. In the first, finely differentiated sensations are formed, and in the second, more complex forms of reflection of the external world.

Scattered elements represent those neurons that are outside the nucleus and perform simpler functions.

On the basis of morphological and experimental-physiological data in the cerebral cortex, the most important cortical ends of the analyzers (centers), which through interaction provide brain functions, have been identified.

Localization of the cores of the main analyzers is as follows:

Cortical end of the motor analyzer (precentral gyrus, precentral lobule, posterior part of the middle and inferior frontal gyrus). The precentral gyrus and the anterior part of the pericentral lobule are part of the precentral region - the motor or motor zone of the cortex (cytoarchitectonic fields 4, 6). In the upper part of the precentral gyrus and the precentral lobule are the motor nuclei of the lower half of the body, and in the lower part - the upper one. The largest area of \u200b\u200bthe entire zone is occupied by the centers of innervation of the hand, face, lips, tongue, and a smaller area, the centers of innervation of the muscles of the trunk and lower extremities. Previously, this area was considered only motor, but now it is considered the area in which the insertion and motor neurons are located. Interneurons perceive stimuli from proprioceptors in bones, joints, muscles, and tendons. The centers of the motor zone provide innervation to the opposite part of the body. Dysfunction of the precentral gyrus leads to paralysis on the opposite side of the body.

The core of the motor analyzer of the combined rotation of the head and eyes in the opposite direction, as well as Motor nuclei of written speech - graphs related to arbitrary movements associated with writing letters, numbers and other signs are localized in the posterior part of the middle frontal gyrus (field 8) and at the border of the parietal and occipital lobes (field 19) ... The center of the graphy is closely related to the field 40, located in the supra-marginal gyrus. If this area is damaged, the patient cannot make the movements that are necessary to draw letters.

Premotor zone located anterior to the motor areas of the cortex (fields 6 and 8). The processes of the cells of this zone are connected both with the nuclei of the anterior horns of the spinal cord and with the subcortical nuclei, the red nucleus, the substantia nigra, etc.

The core of the motor analyzer of speech articulation (speech-motor analyzer) are located in the posterior part of the inferior frontal gyrus (field 44, 45, 45a). In field 44 - Broca's zone, in right-handers - in the left hemisphere, the analysis of stimuli from the motor apparatus is carried out, through which syllables, words, phrases are formed. This center was formed next to the projection area of \u200b\u200bthe motor analyzer for the muscles of the lips, tongue, and larynx. When he is defeated, a person is able to pronounce separate speech sounds, but he loses the ability to form words from these sounds (motor or motor aphasia). In the case of damage to field 45, it is observed: agrammatism - the patient loses the ability to make sentences out of words, to coordinate words into sentences.

Cortical end of the motor analyzer of complex coordinated movements in right-handers, it is located in the inferior parietal lobe (field 40) in the region of the supra-marginal gyrus. When the field 40 is damaged, the patient, despite the absence of paralysis phenomena, loses the ability to use household items, loses production skills, which is called apraxia.

Cortical end of the general sensitivity skin analyzer - temperature, painful, tactile, musculo-articular - located in the postcentral gyrus (fields 1, 2, 3, 5). Violation of this analyzer leads to loss of sensitivity. The sequence of the location of the centers and their territory corresponds to the motor cortex zone.

Cortical end of the auditory analyzer (field 41) is placed in the middle of the superior temporal gyrus.

Auditory Speech Analyzer (control of one's speech and perception of someone else's) is located in the posterior part of the superior temporal gyrus (field 42) (Wernicke's zone_ when it is violated, a person hears speech, but does not understand it (sensory aphasia)

Cortical end of the visual analyzer (fields 17, 18, 19) occupies the edges of the spur sulcus (field 17), complete blindness occurs with bilateral damage to the nuclei of the visual analyzer. In cases of damage to fields 17 and 18, loss of visual memory is observed. When the field is damaged, 19 people lose the ability to orient themselves in a new environment for them.

Visual analyzer of written signs located in the angular gyrus of the inferior parietal lobe (field 39s). When this field is damaged, the patient loses the ability to analyze the written letters, that is, loses the ability to read (alexia)

Cortical ends of the olfactory analyzer are located in the hook of the parahippocampal gyrus on the inferior surface of the temporal lobe and hippocampus.

Cortical ends of the flavor analyzer - in the lower part of the postcentral gyrus.

Cortical end of the stereognostic sense analyzer - the center of a particularly complex type of recognition of objects by touch is in the upper parietal lobe (field 7). If the parietal lobe is damaged, the patient cannot recognize the object by feeling it with the hand opposite to the lesion focus - stereognosy. Distinguish auditory gnosia - recognition of objects by sound (bird - by voice, car - by engine noise), visual gnosia - recognition of objects by sight, etc. Praxia and gnosia are functions of a higher order, the implementation of which is associated with both the first and the second signaling system, which is a specific function of a person.

Any function is localized not in one specific field, but only predominantly associated with it and spreads over a large extent.

Speech- is one of the phylogenetically new and most complexly localized functions of the cortex, associated with the second signaling system, according to I.P. Pavlov. Speech appeared in the course of human social development, as a result of labor activity. "... First, labor, and then articulate speech with it, were the two most important stimuli, under the influence of which the monkey's brain gradually turned into a human brain, which, with all its resemblance to monkeys, far surpasses it in size and perfection" ( K. Marx, F. Engels)

The function of speech is extremely complex. It cannot be localized in any part of the cortex; the entire cortex is involved in its implementation, namely, neurons with short processes located in its surface layers. With the development of new experience, speech functions can move to other areas of the cortex, like gesticulation of the deaf and dumb, reading of the blind, writing with a foot in the armless. It is known that in most people - right-handed people - speech functions, functions of recognition (gnosia), purposeful action (praxia) are associated with certain cytoarchitectonic fields of the left hemisphere, in left-handers - vice versa.

Associative zones of the cortex occupy the rest of a significant part of the cortex, they are devoid of explicit specialization, are responsible for the integration and processing of information and programmed action. The associative cortex is the basis of higher processes like memory, learning, thinking, speech.

There are no thought-generating zones. To make the smallest decision, the entire brain is involved, various processes take place in different zones of the cortex and in the lower nerve centers.

The cerebral cortex receives information, processes it and stores it in memory. In the process of adaptation (adaptation) of the organism to the external environment, complex systems of self-regulation and stabilization were formed in the cortex, providing a certain level of function, self-learning systems with a memory code, control systems operating on the basis of the genetic code, taking into account age and providing an optimal level of control and functions in the body. , comparison systems that ensure the transition from one form of management to another.

Connections between the cortical ends of one or another analyzer with peripheral regions (receptors) are carried out by the system of the pathways of the brain and spinal cord and peripheral nerves extending from them (cranial and spinal nerves).

Subcortical nuclei.The bases of the telencephalon are located in the white matter and form three paired clusters of gray matter: striatum, amygdala and hedge, which make up approximately 3% of the volume of the hemispheres.

Striped bodieso consists of two nuclei: caudate and lenticular.

Caudate nucleus is located in the frontal lobe and is an arc-shaped formation lying on top of the optic tubercle and lenticular nucleus. It consists of head, body and tail, which take part in the formation of the lateral part of the wall of the anterior horn of the lateral ventricle of the brain.

Lenticular kernel a large pyramidal accumulation of gray matter, located outside of the caudate nucleus. The lenticular core is divided into three parts: outer, dark-colored - shell and two light medial stripes - external and internal segments pallidum.

From each other caudate and lenticular nuclei separated by a layer of white matter - part inner capsule... Another part of the inner capsule separates the lenticular nucleus from the underlying thalamus.

The striated body forms striopallidal system, in which the more ancient structure in phylogenetic terms is the pallidum - pallidum... It is isolated as an independent morpho-functional unit that performs a motor function. Thanks to connections with the red nucleus and the black substance of the midbrain, the pallidum realizes the movements of the trunk and arms when walking - cross-coordination, a number of auxiliary movements when changing body positions, facial movements. The destruction of the globus pallidus causes muscle rigidity.

The caudate nucleus and the shell of the younger structures of the striatum - striatum, which does not directly have a motor function, but performs a controlling function in relation to the pallidum, somewhat inhibiting its influence.

With the defeat of the caudate nucleus in humans, rhythmic involuntary movements of the limbs (Huntington's chorea) are observed, with degeneration of the shell, trembling of the limbs (Parkinson's disease).

Fence- a relatively thin strip of gray matter located between the crust of the islet, separated from it by white matter - outer capsule and the shell from which it separates outer capsule... The fence is a complex formation, the connections of which have been little studied until now, and the functional significance is not clear.

Amygdala - a large nucleus, located under the shell in the depths of the anterior temporal lobe, has a complex structure and consists of several nuclei, differing in cellular composition. The amygdala is the subcortical olfactory center and is part of the limbic system.

The subcortical nuclei of the telencephalon function in close relationship with the cerebral cortex, diencephalon and other parts of the brain, and take part in the formation of both conditioned and unconditioned reflexes.

Together with the red nucleus, the black matter of the midbrain, the thalamus of the diencephalon, the subcortical nuclei form extrapyramidal system, carrying out complex unconditioned reflex motor acts.

Olfactory brain human is the most ancient part of the telencephalon, which arose in connection with the olfactory receptors. It is divided into two sections: peripheral and central.

To the peripheral department include: the olfactory bulb, the olfactory tract, the olfactory triangle, and the anterior perforation.

Part central departmentbut includes: vaulted gyrus, consisting of cingulate gyrus, isthmus and parahippocampal gyrus, and hippocampus - a peculiarly shaped formation located in the cavity of the lower horn of the lateral ventricle and dentate gyruslying inside the hippocampus.

Limbic system (border, edge) is so named because the cortical structures included in it are located at the edge of the neocortex and, as it were, border the brain stem. The limbic system includes both certain zones of the cortex (archipaleocortical and interstitial areas) and subcortical formations.

Of the cortical structures, these are: hippocampus with dentate gyrus(old bark), cingulate gyrus (the limbic cortex, which is intermediate), olfactory cortex, septum (ancient crust).

From subcortical structures: mammillary body of the hypothalamus, anterior nucleus of the thalamus, amygdala complex, and vault.

In addition to the numerous two-way connections between the structures of the limbic system, there are long paths in the form of closed circles through which the circulation of excitation occurs. The large limbic circle - peipz circle includes: hippocampus, vault, mammillary body, mastoid-thalamic bundle (bunch of Vic d "Azira), anterior nucleus of the thalamus, cingulate cortex, hippocampus... Of the overlying structures, the limbic system has the closest connections with the frontal cortex. The limbic system directs its descending paths to the reticular formation of the brainstem and to the hypothalamus.

Through the hypothalamic-pituitary system, it exercises control over the humoral system. The limbic system is characterized by a special sensitivity and a special role in the functioning of hormones synthesized in the hypothalamus oxytocin and vasopresin, secreted by the pituitary gland.

The main integral function of the limbic system is not only the olfactory function, but also the reactions of the so-called innate behavior (food, sexual, search and defensive). It carries out the synthesis of afferent stimuli, is important in the processes of emotional-motivational behavior, organizes and ensures the flow of vegetative, somatic and mental processes during emotional-motivational activity, carries out the perception and storage of emotionally significant information, the choice and implementation of adaptive forms of emotional behavior.

So, the functions of the hippocampus are associated with memory, learning, the formation of new behavioral programs when conditions change, in the formation of emotional states. The hippocampus has extensive connections with the cerebral cortex and the hypothalamus of the diencephalon. In mentally ill patients, all layers of the hippocampus are affected.

At the same time, each structure that is part of the limbic system contributes to a single mechanism, having its own functional features.

Anterior limbic cortexprovides emotional expressiveness of speech.

Cingulate gyrustakes part in the reactions of alertness, awakening, emotional activity. It is connected by fibers to the reticular formation and the autonomic nervous system.

Almond complex responsible for eating and defensive behavior, stimulation of the amygdala induces aggressive behavior.

Partitiontakes part in retraining, reduces aggressiveness and fear.

Mamillary bodies play a large role in the development of spatial skills.

Anterior to the vault the centers of pleasure and pain are located in its various departments.

Lateral ventricles are the cavities of the cerebral hemispheres. Each ventricle has a central part adjacent to the upper surface of the optic tubercle in the parietal lobe and three horns extending from it.

Front horn recedes into the frontal lobe, rear horn - into the occipital lobe, the lower horn - into the depth of the temporal lobe. In the lower horn there is an elevation of the inner and partly the lower wall - the hippocampus. The medial wall of each anterior horn is a thin transparent plate. The right and left plates form a common transparent septum between the anterior horns.

The lateral ventricles, like all the ventricles of the brain, are filled with cerebral fluid. Through the interventricular openings, which are in front of the optic hillocks, the lateral ventricles communicate with the third ventricle of the diencephalon. Most of the walls of the lateral ventricles are formed by the white matter of the cerebral hemispheres.

White matter of the telencephalon.Formed by fibers of the pathways, which are grouped into three systems: associative or combination, commissural or adhesive and projection.

Associative fibers the telencephalon connect different parts of the cortex within the same hemisphere. They are divided into short fibers lying superficially and arcuate, connecting the cortex of two adjacent gyri and long fibers lying deeper and connecting parts of the cortex that are distant from each other. These include:

1) Belt, which can be traced from the anterior perforated substance to the gyrus of the hippocampus and connects the cortex of the gyrus of the medial part of the hemisphere surface - refers to the olfactory brain.

2) Lower longitudinal bundle connects the occipital lobe with the temporal lobe, runs along the outer wall of the posterior and lower horns of the lateral ventricle.

3) Upper longitudinal bundle connects the frontal, parietal and temporal lobes.

4) Hooked bunch connects the rectum and orbital gyrus of the frontal lobe with the temporal.

Commissural nerve pathways connect the areas of the cortex of both hemispheres. They form the following commissures or adhesions:

1) Corpus callosum the largest commissure, which connects different parts of the neocortex of both hemispheres. In humans, it is much higher than in animals. In the corpus callosum, the front end curved downward (beak) is distinguished - the knee of the corpus callosum, the middle part - the trunk of the corpus callosum and the thickened posterior end - the corpus callosum ridge. The entire surface of the corpus callosum is covered with a thin layer of gray matter - a gray vestment.

In women, more fibers pass in a certain area of \u200b\u200bthe corpus callosum than in men. Thus, interhemispheric connections in women are more numerous, in this regard, they have a better integration of information available in both hemispheres, and this explains gender differences in behavior.

2) Anterior corpus callosumlocated behind the beak of the corpus callosum and consists of two bundles; one connects the anterior perforated substance, and the other connects the gyrus of the temporal lobe, mainly the hippocampal gyrus.

3) Arch soldering connects the central parts of two arcuate bundles of nerve fibers, which form a vault located under the corpus callosum. In the vault, a central part is distinguished - the columns of the vault and the legs of the vault. The pillars of the vault connect a triangular plate - the vault ridge, the posterior section of which is spliced \u200b\u200bwith the lower surface of the corpus callosum. The pillars of the arch, curving backward, enter the hypothalamus and end in the nipple-shaped bodies.

Projection pathways connect the cortex of the cerebral hemispheres with the nuclei of the brain stem and spinal cord. Distinguish: efferent - the descending motor pathways that conduct nerve impulses from the cells of the motor areas of the cortex to the subcortical nuclei, motor nuclei of the brain stem and spinal cord. Thanks to these paths, the motor centers of the cerebral cortex are projected onto the periphery. Afferent - the ascending sensory pathways are the processes of the cells of the spinal ganglia and the ganglion of the cranial nerves - these are the first neurons of the sensory pathways that end on the switching nuclei of the spinal cord or medulla oblongata, where the second neurons of the sensory pathways are located, going as part of the medial loop to the ventral nuclei of the thalamus. These nuclei contain the third neurons of the sensory pathways, the processes of which go to the corresponding nuclear centers of the cortex.

Both sensory and motor pathways form in the material of the cerebral hemispheres a system of radially diverging beams - a radiant crown, gathering in a compact and powerful beam - an internal capsule that is located between the caudate and lenticular nuclei, on the one hand, and the thalamus, on the other hand. It distinguishes between the front leg, the knee and the hind leg.

The pathways of the brain and these are the spinal pathways.

The meninges of the brain.The brain, like the spinal cord, is covered with three membranes - hard, arachnoid and vascular.

Hard shelland the brain differs from that of the spinal cord in that it is fused with the inner surface of the bones of the skull, there is no epidural space. The dura mater forms channels for the outflow of venous blood from the brain - the sinuses of the dura mater and gives out processes that provide fixation of the brain - this is the cerebral crescent (between the right and left hemispheres of the brain), the outline of the cerebellum (between the occipital lobes and the cerebellum) and the saddle diaphragm (above the Turkish saddle, in which the pituitary gland is located). In the places of origin of the processes, the dura mater exfoliates, forming sinuses, where the venous blood of the brain, dura mater, and skull bones flows into the system of external veins through the graduates.

Arachnoidof the brain is located under the solid and covers the brain, not entering its furrows, spreading over them in the form of bridges. On its surface there are outgrowths - pachyon granulations that have complex functions. Between the arachnoid and the choroid, a subarachnoid space is formed, well expressed in the cisterns, which are formed between the cerebellum and the medulla oblongata, between the brain legs, in the area of \u200b\u200bthe lateral groove. The subarachnoid space of the brain communicates with those of the spinal cord and the fourth ventricle and is filled with circulating cerebral fluid.

Choroid the brain consists of 2 plates, between which are located arteries and veins. It is closely intertwined with the substance of the brain and enters all the cracks and grooves and participates in the formation of vascular plexuses, rich in blood vessels. Penetrating into the ventricles of the brain, the choroid produce cerebral fluid, thanks to its vascular plexus.

Lymphatic vessels in the membranes of the brain are not found.

The innervation of the membranes of the brain is carried out by the V, X, XII pairs of cranial nerves and the sympathetic nerve plexus of the internal carotid and vertebral arteries.

Terms used

Position relative to the center of mass and the longitudinal axis of the body or outgrowth of the body

• Abaxial (antonym: adaxial) - located further from the axis.
• Adaxial (antonym: abaxial) - located closer to the axis.
• Apical (antonym: basal) - located at the top.
• Basal (antonym: apical) - located at the base.
• Distal (antonym: proximal) - distant.
• Lateral (antonym: medial) - lateral.
• Medial (antonym: lateral) - middle.
• Proximal (antonym: distal) - close.

Position relative to the main body parts

• Aboral (antonym: adoral) - located at the opposite pole of the mouth of the body.
• Adoral (oral) (antonym: aboral) - located near the mouth.
• Ventral (antonym: dorsal) - abdominal.
• Dorsal (antonym: ventral) - dorsal.
• Caudal (antonym: cranial) - caudal, located closer to the tail or to the rear end of the body.
• Cranial (antonym: caudal) - head, located closer to the head or to the front end of the body.
• Rostral - nasal, literally - located closer to the beak. Located closer to the head or to the front end of the body.

Basic planes and cuts

• Sagittal - an incision in the plane of bilateral symmetry of the body.
• Parasagittal - an incision running parallel to the plane of bilateral symmetry of the body.
• Frontal - an incision running along the anteroposterior axis of the body perpendicular to the sagittal one.
• Axial - an incision in the transverse plane of the body

Methods of drug administration

• orally - through the mouth;
• intradermally, intradermally (lat. intracutaneous or intradermal);
• subcutaneously (lat. subcutaneous);
• intramuscularly (lat. intramuscular);
• intravenously (lat. intravenous);
• rectally - through the anus;
• sublingually - under the tongue.

Directions

In animals, there is usually a head at one end of the body, and a tail at the opposite end. The head end in anatomy is called cranial, cranialis (cranium - skull), and the tail is called caudal, caudalis (cauda - tail). On the head itself, they are guided by the nose of the animal, and the direction to its tip is called rostral, rostralis (rostrum - beak, nose).

The surface or side of the animal's body directed upwards, against gravity, is called dorsal, dorsalis (dorsum - back), and the opposite side of the body, which is closest to the ground, when the animal is in its natural position, that is, it walks, flies or swims - ventral, ventralis (venter - belly). For example, a dolphin's dorsal fin is located dorsally, and the udder of the cow on ventral side.

Right, dexterand left, sinister, the sides are designated as they could be presented from the point of view of the studied animal. Term homolateral, less often ipsilateral indicates location on the same side and contralateral - located on the opposite side. Bilaterally - means location on both sides.

All descriptions in human anatomy are based on the assumption that the body is in the position of the anatomical stand, that is, the person is standing straight, arms are lowered, palms are facing forward.

Areas closer to the head are called upper; farther - lower... Upper, superior, corresponds to the concept cranial, and the bottom, inferior, - the concept caudal. Front, anteriorand rear, posterior, correspond to the concepts ventral and dorsal... Moreover, the terms front and rear in relation to four-legged animals are incorrect, the concepts should be used ventral and dorsal.

Central - located in the center of the body or anatomical region;
peripheral - external, remote from the center.

When describing the position of organs lying at different depths, the following terms are used: deep, profundusand surface, superficialis.

Concepts outer, externusand interior, internusare used to describe the position of structures in relation to various body cavities.

The term visceral, visceralis (viscerus - the inside) denote belonging and close location with any organ. AND parietal, parietalis (paries - wall) - means related to any wall. For example, visceral pleura covers the lungs, while parietal the pleura covers the inner surface of the chest wall.

Limbs

The surface of the upper limb relative to the palm is designated by the term palmaris - palmar, and the lower limb relative to the sole - plantaris - plantar.

The edge of the forearm from the side of the radius is called ray, radialis, and from the side of the ulna - elbow, ulnaris... On the lower leg, the edge where the tibia is located is called tibial, tibialis, and the opposite edge, where the fibula lies - fibular, fibularis.

Proximal and distal

Proximal (from lat. proximus - closest) term indicating the location of an organ or its part closer to the center of the body or to its median (median) plane; opposite to term distal, for example, in a human hand, the shoulder is the proximal section, and the hand is the distal one.

Planes

In animal and human anatomy, the concept of the main projection planes is accepted.

• The vertical plane divides the body into left and right parts;
• the frontal plane divides the body into dorsal and ventral parts;
• a horizontal plane divides the body into cranial and caudal parts.

Application in human anatomy

The ratio of the body to the main projection planes is important in medical imaging systems such as computed and magnetic resonance imaging, positron emission tomography. In such cases, the body of a person in anatomical rack, is conventionally placed in a three-dimensional rectangular coordinate system. In this case, the plane YX turns out to be located horizontally, the axis X located in anteroposterior direction, axis Y goes left to right or right to left, and the axis Z goes up and down, that is, along the human body.

• Sagittal plane, XZ, separates the right and left halves of the body. A special case of the sagittal plane is median plane, it passes exactly in the middle of the body, dividing it into two symmetrical halves.
• Frontal plane, or coronal, YZ, also located vertically, perpendicular to the sagittal, it separates the anterior (ventral) part of the body from the posterior (dorsal) part.
• Horizontal, axial, or transverse plane, XY, perpendicular to the first two and parallel to the surface of the earth, it separates the overlying parts of the body from the underlying ones.

These three planes can be drawn through any point of the human body; the number of planes can be arbitrary. In addition, in systematic anatomy, a number of other planes are used to determine the topography of internal organs: horizontal transpyloric, planum transpyloricum, which passes through the middle of the line connecting the notch of the sternum with the pubic symphysis; horizontal: hypochondrium, planum subcostale, passing through the lowest points of the costal arch; supra-crestal, planum supracristale, connecting the uppermost points of the iliac crests; intertubular plane, planum intertuberculare, passing through the upper anterior iliac spine of the iliac bones, etc.

Movement

The term flexion, flexio, indicate the movement of one of the bone levers around frontal axis, at which the angle between the articulating bones decreases. For example, when a person sits down, flexion in the knee joint decreases the angle between the thigh and lower leg. Movement in the opposite direction, that is, when the limb or trunk is straightened, and the angle between the bony levers increases, is called extension, extensio.

An exception is the ankle (supratar) joint, in which extension is accompanied by upward movement of the fingers, and when flexing, for example, when a person stands on tiptoe, the fingers move downward. Therefore, flexion of the foot is also called plantar flexion, and foot extension is denoted by the term dorsiflexion.

Movements around sagittal axis are bringing, adductioand diversion, abductio... Adduction - the movement of the bone towards the median plane of the body or (for fingers) to the axis of the limb, abduction characterizes the movement in the opposite direction. For example, when the shoulder is abducted, the hand is raised to the side, and the adduction of the fingers leads to their closure.

Under rotation, rotatiounderstand the movement of a body part or bone around their longitudinal axis... For example, head rotation occurs due to the rotation of the cervical spine. Rotation of the limbs is also indicated by the terms pronation, pronatio, or inward rotationand supination, supinatio, or outward rotation... During pronation, the palm of the freely hanging upper limb turns back, and during supination - forward. Pronation and supination of the hand are carried out due to the proximal and distal radioulnar joints. The lower limb rotates around its axis mainly due to the hip joint; pronation orients the toe of the foot inward, and supination - outward. If, when moving around all three axes, the end of the limb describes a circle, such a movement is called circular, circumductio.

Tooth surfaces. For the convenience of describing the features of the relief or localization of pathological processes, 5 surfaces of the tooth crown are conventionally distinguished (Fig. 1).

Fig. 1 . Surface (a), edge (b) and axis (c) of the tooth

1. Occlusal surface (fades occlusalis) faces the teeth of the opposite jaw. It is found in molars and premolars. The incisors and canines at the ends facing the antagonists have incisal edge (margo incisalis).

2. Vestibular surface (facies vestibularis) is oriented in the vestibule of the mouth. For the front teeth that come in contact with the lips, this surface may be called labial (facies labialis), and at the back, adjacent to the cheek, - buccal (facies buccalis).

The continuation of the tooth surface to the root is indicated as vestibular root surface, and the wall of the dental alveoli, covering the root from the vestibule of the mouth, is like vestibular alveolar wall.

3. Lingual surface (facies lingualis) facing the mouth towards the tongue. For upper teeth, the name applies palatal surface (facies palatinalis)... Also called the surface of the root and the walls of the alveoli, directed into the actual oral cavity.

4. Proximal surface (facies approximalis) adjacent to the adjacent tooth. There are two such surfaces: mesial surface (facies mesialis)facing the middle of the dental arch, and distal (facies distalis)... Similar terms are used to refer to the roots of the teeth and the corresponding parts of the alveoli. On these surfaces is area contingens.

Also common are terms denoting directions in relation to the tooth: medially, distally, vestibularly, lingually, occlusally and apically.

When examining and describing teeth, the terms "vestibular norm", "occlusal norm", "lingual norm", etc. are used. The norm is the position established during the study. For example, the vestibular norm is such a position of the tooth in which it faces the investigator with the vestibular surface.

Crown and root of the tooth it is customary to divide into thirds. So, when dividing a tooth with horizontal planes, the occlusal, middle and cervical (cervical) thirds are distinguished in the crown, and in the root - the cervical (cervical), middle and apical (apical) thirds. With sagittal planes, the crown of the anterior teeth is divided into medial, middle and distal third, and by the frontal planes - on the vestibular, middle and lingual third.

The dental system as a whole. The protruding parts of the teeth (crowns) are located in the jaws, form dental arches (or rows): the upper ( arcus dentalis maxillaris (superior) and lower (arcus dentalis mandibularis (inferior)... In adults, both dental arches contain 16 teeth: 4 incisors, 2 canines, 4 small molars, or premolars, and 6 large molars, or molars. When the jaws are closed, the teeth of the upper and lower dental arches are in certain relationships with each other. So, the cusps of molars and premolars of one jaw correspond to the indentations on the teeth of the same name of the other jaw. Opposite incisors and canines touch one another in a certain order. This ratio of closed teeth of both dentition is called occlusion (Fig. 2).

Fig. 2. The ratio of the upper and lower dentition in the central occlusion:

a - the direction of the axes of the teeth; b - diagram of the location of antagonist teeth

The contacting teeth of the upper and lower jaws are called antagonistic teeth... As a rule, each tooth has two antagonists - the main one and the additional one. The exception is the medial lower incisor and the 3rd upper molar, which usually have one antagonist each. The teeth of the same name on the right and left sides are called antimers.

Dental formula. The order of the teeth is recorded in the form of a dental formula, in which individual teeth or their groups are recorded in numbers or letters and numbers. In the complete formula of the teeth, the teeth of each half of the jaws are recorded ordinal Arabic numerals... This formula for an adult looks like the writer examines the teeth of the person sitting in front of him. This formula is called clinical. When examining patients, clinicians note missing teeth. If all teeth are preserved, the dentition is called complete.

Each tooth, in accordance with the complete clinical formula, can be designated separately: upper right - by a sign; top left; lower right; lower left. For example, left lower second molar is designated and right upper second premolar.

The World Health Organization (WHO) has adopted a complete clinical dental formula in a different form:

Milk teeth in the full formula are denoted by Roman numerals:

Individual deciduous teeth are indicated in the same way.

According to the WHO classification, the complete clinical dental formula for the milk dentition is written as follows:

In this case, the lower left canine is 73 and the upper right first molar is 54.

There are group dental formulas, reflecting the number of teeth in each group by half of the jaw, which can be used in anatomical studies (for example, in comparative anatomical studies). This formula is called anatomical. The group dental formulas of an adult and a child with milk teeth are as follows:

Such a group formula of teeth means that in each half of the upper and lower jaws (or half of the dentition) there are 2 incisors, 1 canine, 2 premolars, 3 molars. Since both halves of the dental arches are symmetrical, you can write one half or a quarter of the formula.

The group dental formula can be written using the initial letters of the Latin names of the teeth (I - incisors, C - canines, P - premolars, M - molars). Permanent teeth are designated in uppercase, milk teeth - in lowercase letters. Teeth formulas are as follows:

In letters and numbers, you can write down the complete formula of the teeth:

It is convenient to use this alphanumeric formula when examining children with milk teeth, whose permanent teeth have partially erupted. For example, a 10-year-old child's complete tooth formula might be:

Individual teeth according to this formula are designated with an angle sign, indicating the tooth group and its serial number. For example, a right upper second premolar should be written like this:, left lower second molar:, milk right upper first molar: t 1.

Human anatomy S.S. Mikhailov, A.V. Chukbar, A.G. Tsybulkin