External nose structure. External nose
The tissues of the lungs are quite delicate, and therefore the air entering them must have certain characteristics - be warm, moist and clean. When breathing through the mouth, these qualities cannot be achieved, which is why nature created the nasal passages, which, together with neighboring sections, make the air ideal for the respiratory organ. With the help of the nose, the inhaled stream is cleared of dust, moistened and warmed. Moreover, it does this while passing through all departments.
Functions of the nose and nasopharynx
The nose consists of three parts. They all have their own characteristics. All sections are covered with a mucous membrane and the more of it, the better the air is processed.
It is important that this type of tissue is not susceptible to pathological conditions. In general, the nose performs the following functions:
- Heating cold air and preserving it;
- Cleansing from pathogens and air pollutants (using the mucous surface and hairs on it);
- Thanks to the nose, each person has his own and unique timbre of voice, that is, the organ also works as a resonator;
- Discrimination of odors by olfactory cells located in the mucosa.
Each part of the nose is structured differently and is responsible for a specific job. At the same time, the rather complex structure of osteochondral tissue allows for better processing of the incoming air flow into the lungs.
General structure
When we talk about departments, we mean the three components of the nasal system. They differ in their structure. Moreover, for each person, some elements may differ in general, but at the same time play their role in the process of breathing and smell, as well as protection. Therefore, to simplify, the following parts are distinguished:
- Outdoor;
- Nasal cavity;
- Sinuses.
They all have common features among all people, but at the same time they also have differences. This depends on the individual anatomical characteristics, as well as on the age of the person.
Structure of the external part
The outer part is formed by the bones of the skull, cartilaginous plates, muscle and skin tissue. The shape of the external nose resembles a triangular irregular pyramid, in which:
- The apex is the bridge of the nose between the eyebrows;
- The dorsum is the surface of the olfactory organ, consisting of two lateral bones;
- Cartilaginous tissue continues the bone, forming the tip and wings of the nose;
- The tip of the nose meets the columella, a septum that forms and separates the nostrils;
- All this is covered from the inside with mucous membranes and hairs, and on the outside – with skin.
The wings of the nose are supported by muscle tissue. A person does not actively use them, and therefore they are attributed more to the facial department, which helps to reflect the emotional state of a person.
The skin in the nose area is quite thin and equipped with a large number of blood vessels and nerve endings. The columella is usually not perfectly straight and has a slight curvature. At the same time, in the area of the septum there is also a Kisselbach zone, where there is a large accumulation of blood vessels and nerve endings, almost at the very surface of the integument.
This is why nosebleeds occur most often here. Also, this area, even with minimal trauma to the nose, gives severe pain.
If we talk about the differences in this part of the olfactory organ in different people, then in adults it can differ in shape (which is influenced by previous injuries, pathologies, as well as heredity), and in adults and children – in structure.
The nose is formed until about 15 years of age, although according to statistical data from researchers, the nose “matures” and grows with a person throughout life.
Newborns have a different nose from an adult. The outer part is quite small, although it consists of the same sections. But at the same time, it is just beginning to develop, and therefore children of this period often immediately pick up all sorts of inflammations and pathogens.
The olfactory organ in children cannot perform the same functions as in adults in full. The ability to warm air develops at about 5 years of age. Therefore, even in frosts of -5 - -10 degrees, the tip of a child’s nose quickly freezes.
The picture shows a diagram of the structure of the human nasal cavity
Anatomy of the nasal cavity
The physiology and anatomy of the nose primarily implies the internal structure in which vital processes occur. The organ cavity has its own boundaries, which are formed by the bones of the skull, oral cavity, and eye sockets. Consists of the following parts:
- The nostrils, which are the entrance gates;
- Hoan - two holes in the back of the internal cavity that lead to the upper half of the pharynx;
- The septum consists of cranial bones with a cartilaginous plate, which forms the nasal passages;
- The nasal passages, in turn, consist of walls: superior, medial internal, lateral external, and also formed by the maxillary bones.
If we talk about the departments of this area, they can be conditionally divided into lower, middle, upper with the corresponding respiratory passages. The upper passages exit to the frontal sinuses, the lower one carries the lacrimal secretion into the cavity. The middle one leads to the maxillary sinuses. The nose itself consists of:
- The vestibules are zones of epithelial cells within the wings of the nose with a large number of hairs;
- The respiratory zone is responsible for producing mucus to humidify and cleanse the air of pollutants;
- The olfactory area helps to distinguish odors due to the presence of corresponding receptors and olfactory cilia in the tissues.
In children, the internal structure is generally similar to that of an adult, but at the same time it is located quite densely due to the underdevelopment of the department. That is why this department gives frequent complications in the form.
The passages of the nose are narrow, and the structure of the mucous membrane is distinguished by a large number of blood vessels, which provokes almost immediate swelling under the influence of hypothermia, a pathogen or an allergen.
Simple and accessible information about the structure of the nasal cavity in our video:
The structure of the paranasal sinuses
The sinuses are an additional device for air ventilation, which are also lined with mucous surfaces and are a natural extension of the nasal passage system. The department consists of:
- The maxillary sinuses are the largest section of this type with a wide opening that is covered by the mucous membrane, leaving only a small gap. It is precisely because of the peculiarities of this structure that all sorts of infectious lesions of this section often develop with difficult removal of “waste products”. They are located on the sides of the nose in the area of the cheeks under the eyes.
- The frontal sinus is located in the area above the eyebrows just above the bridge of the nose.
- The third largest section is the cells of the ethmoid bone.
- The sphenoid sinus is the smallest.
Each department can be affected by a specific disease, which is named accordingly. In general, pathologies of this part of the nose are called sinusitis.
The paranasal sinuses are extremely important in the structure of the nose, as they ultimately warm and moisturize the air flow coming from the outside, and also organize the sense of smell. Free cavities reduce the weight of the skull, reducing the load on the spine. In case of injury, they help soften the force of the blow, and also participate in the formation of the timbre of the voice.
At birth, a child has formed cells of the ethmoid labyrinth and the rudiments of the maxillary sinuses. Gradually, the structure of the labyrinth changes, increasing in volume. The maxillary cavities are finally formed only by the age of 12. The frontal and sphenoid sinuses begin to develop only from 3-5 years.
Visual video with diagrams of the structure and location of the paranasal sinuses:
Common pathologies and diseases
External nose
Taking into account the peculiarities of the anatomical structure of the nose, each section can affect its own range of diseases and injuries. For the external department it is:
- Erysipelas;
- Burns and injuries;
- Developmental anomalies;
- Eczema;
- Sycosis of the nasal vestibule;
- and rosacea.
Nasopharynx
The inside of the nose, in turn, can be affected by the following pathologies.
The nose (nasus) consists of the external nose and the nasal cavity.
The external nose (nasus externus) is represented by a pyramid-shaped osteocartilaginous frame (Fig. 1.1), covered with skin. It distinguishes between the tip, root (bridge of the nose), back, slopes and wings.
Rice. 1.1. External nose.
: 1 - nasal bone; 2 - frontal process of the upper jaw; 3 - triangular lateral cartilage; 4 - large cartilages of the wings of the nose; 5 - cartilage of the nasal septum, b - side view: 6 - sesamoid cartilage.
The bony part of the skeleton consists of paired flat nasal bones and the frontal processes of the upper jaw. These bones, together with the anterior nasal spine, form the pyriform opening of the facial skeleton. The cartilaginous part of the skeleton consists of paired triangular and alar cartilages, as well as accessory cartilages; the wings of the nose in their lower posterior part lack a cartilaginous base.
The skin in the lower third of the nose has many sebaceous glands. Bending over the edge of the entrance to the nose (nostrils), it lines the walls of the vestibule of the nose (vestibulum nasi) for 4-5 mm.
Here there is a large amount of hair on the skin, which causes the possibility of boils and sycosis.
In the area of the wings of the nose, under the skin, there are muscles that widen and narrow the entrance to the nose.
The external nose, like all soft tissues of the face, is characterized by an abundant blood supply: it receives anastomosing branches from the maxillary and orbital arteries, from the system of the external and internal carotid arteries, respectively. The veins of the external nose drain blood through the anterior facial vein into the internal jugular vein and in large quantities through the veins of the nasal cavity, then through the orbital veins into the venous plexus of the pterygopalatine fossa (plexus pterygoideus) and into the cavernous sinus (sinus cavernosus), middle cerebral (v. meningea media) and then into the internal jugular (v.jugularis interna) vein.
Lymphatic flow from the external nose is carried out mainly to the submandibular lymph nodes. The muscles of the external nose are nerved by the branches of the facial nerve (n.facialis), the skin - by the first (ophthalmic nerve - n.ophtalmicus) and second (maxillary nerve - n.maxillaris) branches of the trigeminal nerve, supraorbital (n.supraorbitalis) and infraorbital (n.infraorbitalis) nerves.
The plastic skin-cartilaginous structure of the anterior part of the external nose allows it to be shifted to the sides within certain limits without subsequent permanent deformation. However, a strong mechanical impact on the bony part of the nose is often accompanied by fractures of the nasal bones, often with displacement of fragments, and with a more severe injury - a fracture of the frontal processes of the upper jaw.
Basic anatomical formations of the head and neck.
The nose is the most prominent part of the face, located in close proximity to the brain. To understand the mechanisms of development of pathological processes and ways to prevent the spread of infection, it is necessary to know the structural features. The basics of studying at a medical university begin with the alphabet, in this case with the study of the basic anatomical structures of the sinuses.
Being the initial link of the respiratory tract, it is connected with other organs of the respiratory system. The connection with the oropharynx suggests an indirect relationship with the digestive tract, since often mucus from the nasopharynx enters the stomach. Thus, one way or another, pathological processes in the sinuses can affect all these structures, causing diseases.
In anatomy, it is customary to divide the nose into three main structural parts:
- External nose;
- Directly the nasal cavity;
- Paranasal sinuses.
Together they form the main olfactory organ, the main functions of which are:
- Respiratory. It is the first link in the respiratory tract; it is through the nose that inhaled air normally passes; the wings of the nose play the role of auxiliary muscles in case of respiratory failure.
- Sensitive. It is one of the main sense organs, thanks to the receptor olfactory hairs, it is able to capture odors.
- Protective. The mucus secreted by the mucous membrane allows it to retain dust particles, microbes, spores and other large particles, preventing them from passing deep into the body.
- Warming. Passing through the nasal passages, cool air is heated thanks to the mucous capillary vascular network located close to the surface.
- Resonator. Participates in the sound of one’s own voice, determines the individual characteristics of voice timbre.
The video in this article will help you better understand the structure of the paranasal cavities
Let's look at the structure of the nose and sinuses in pictures.
External departments
The anatomy of the nose and paranasal sinuses begins with the study of the external nose.
The outer part of the olfactory organ is represented by bone and soft tissue structures in the form of a triangular pyramid of irregular configuration:
- The upper part is called the dorsum, which is located between the brow ridges - this is the narrowest part of the external nose;
- Nasolabial folds and wings limit the organ on the sides;
- The tip of the nose is called the apex;
Below, on the base, are the nostrils. They are represented by two round passages through which air enters the respiratory tract. Bounded by the wings on the lateral side, and by the septum on the medial side.
The structure of the external nose.
The table shows the main structures of the external nose and the designations where they are located in the photo:
Structure | How they work |
---|---|
Bone frame | · Nasal bones (2), two pieces; · Nasal region of the frontal bone (1); · Processes from the upper jaw (7). |
Cartilaginous part | · Quadrangular cartilage, forming the septum (3); · Lateral cartilages (4); · Large cartilages that form the wings (5); Small cartilages that form wings (6) |
Nasal muscles. | These are predominantly rudimentary, belong to the facial muscles and can be regarded as auxiliary, since they are connected during respiratory failure: · Raising the wing of the nose; · Elevator of the upper lip. |
Blood supply. | The venous network communicates with the intracranial vessels of the head, so hematogenously, infection from the nasal cavity can enter the brain structures, causing serious septic complications. Arterial system: Venous system: |
The structure of the external nose.
Nasal cavity
It is represented by three choanae or nasal conchas, between which the human nasal passages are located. They are localized between the oral cavity and the anterior fossa of the skull - the entrance to the skull.
Characteristic | Top stroke | Average stroke | Bottom stroke |
---|---|---|---|
Localization | The space between the middle and superior conchae of the ethmoid bone. | · The space between the inferior and middle conchae of the ethmoid bone; · divided into basal and sagittal parts. | · The lower edge of the ethmoid bone and the bottom of the nasal cavity; · connected to the ridge of the upper jaw and the bone of the palate. |
Anatomical structures | The olfactory region is the receptor zone of the olfactory tract, exiting into the cranial cavity through the olfactory nerve. The main sinus opens. | Almost all sinuses of the nose open, except for the main sinus. | · Nasolacrimal duct; · The mouth of the Eustachian (auditory) tube. |
Function | Sensitive – smells. | Air flow direction. | Provides outflow of tears and communication with the inner ear (resonator function). |
Structure of the nasal cavity.
When performing rhinoscopy, the ENT doctor can only see the middle passage; beyond the rhinoscope are the upper and lower ones.
Sinuses
The facial bones contain hollow spaces that are normally filled with air and connect to the nasal cavity - these are the paranasal sinuses. There are four types in total.
Photo of the structure of the human sinuses.
Characteristic | Wedge-shaped (basic) (3) | Maxillary (maxillary) (4) | Frontal (frontal) (1) | Lattice (2) |
---|---|---|---|---|
Are opening | Exit to the top passage. | Exit to the middle passage, anastomosis in the upper medial corner. | Middle nasal passage. | · Front and middle – in middle speed; · Rear – to the top. |
Volume | 3-4 cm 3 | 10.-17.3 cm 3 | 4.7 cm 3 | Different |
Peculiarities | Common boundaries with the base of the brain, where are: Pituitary gland, - optic nerves Carotid arteries. | The biggest; Have a triangular shape | From birth they are not visualized; full development occurs by the age of 12. | · Individual quantity for each person – from 5 to 15 rounded hollow holes; |
Blood supply | Pterygopalatine artery; branches of the meningeal arteries | Maxillary artery | Maxillary and ophthalmic arteries | Ethmoidal and lacrimal arteries |
Inflammation of the sinuses | Sphenoiditis | Sinusitis | Frontit | Ethmoiditis |
Normally, air flows through the sinuses. In the photo you can see the structure of the nasal sinuses and their relative position. With inflammatory changes, the sinuses are often filled with mucous or mucopurulent contents.
The paranasal sinuses also communicate with each other, which is why the infection often spreads and flows from one sinus to another.
Maxillary
They are the largest and have a triangular shape:
Wall | Structure | Structures |
---|---|---|
Medial (nasal) | The bony plate corresponds to most of the middle and lower passages. | Excretory anastomosis connecting the sinus to the nasal cavity |
Front (front) | From the lower edge of the orbit to the alveolar process of the upper jaw. | Canine (canine) fossa, 4-7 mm deep. At the upper edge of the fossa, the infraorbital nerve emerges. A puncture is made through this wall. |
Superior (orbital) | Borders the orbit. | The infraorbital nerve passes through the thickness; The venous plexus borders the orbit through the cavernous sinus, located in the dura mater of the brain. |
Rear | Tubercle of the upper jaw. | Pterygopalatine ganglion; Maxillary nerve; Pterygopalatine venous plexus; Maxillary artery; |
Lower (bottom) | Alveolar process of the maxilla. | Sometimes there is protrusion into the sinus of the roots of the teeth. |
Formations of the maxillary paranasal sinus
Lattice
The ethmoid labyrinth is a single bone where the ethmoid sinuses are located in humans, it borders on:
- frontal superior;
- wedge-shaped at the back;
- maxillary from the side.
It may spread into the orbit in the anterior or posterior sections, depending on the individual characteristics of the anatomical structure. Then they border on the anterior fossa of the skull through the cribriform plate.
This justifies the instructions when opening the sinuses - only in the lateral direction, so as not to damage the plate. The optic nerve also passes close to the plate.
Frontal
They have a triangular shape and are located in the scales of the frontal bone. They have 4 walls:
Wall | Peculiarities |
---|---|
Orbital (lower) | Is the upper wall that forms the orbit; Located next to the cells of the ethmoid bone labyrinth and the nasal cavity; The canal is located - this is the connection between the nasal sinuses and the middle nasal meatus, 10-15 mm long and 4 mm wide. |
Facial (front) | The thickest is 5-8 mm. |
Brain (posterior) | Borders the anterior fossa of the skull; Consists of compact bone. |
Medial | Is the septum of the frontal sinuses |
Wedge-shaped
Formed by walls:
Wall | Peculiarities |
---|---|
Lower | Forms the roof of the nasopharynx; the roof of the nasal cavity; Consists of spongy bone. |
Upper | The lower surface of the sella turcica; Above is the area of the frontal lobe (olfactory gyri) and the pituitary gland. |
Rear | Basilar region of the occipital bone; The thickest. |
Lateral | It borders the cavernous sinus and is in close proximity to the internal carotid artery; The oculomotor, trochlear, first branch of the trigeminal and abducens nerves pass through. Wall thickness – 1-2 mm. |
The video in this article will help you understand where exactly the paranasal sinuses are located and how they are formed:
All medical workers and people suffering from sinusitis need to know about the anatomy of the paranasal sinuses. This information will help to understand where the pathological process develops and how it can spread.
The anatomy of the nose and paranasal sinuses is of great clinical importance, since in close proximity to them there is not only the brain, but also many great vessels that contribute to the rapid spread of pathogenic processes.
It is important to understand exactly how the nasal structures communicate with each other and with the surrounding space in order to understand the mechanism of development of inflammatory and infectious processes and effectively prevent them.
The nose, as an anatomical formation, includes several structures:
- external nose;
- nasal cavity;
- paranasal sinuses.
External nose
This anatomical structure is an irregular pyramid with three sides. The external nose is very individual in appearance and has a wide variety of shapes and sizes in nature.
The dorsum delimits the nose from the upper side, it ends between the eyebrows. The top of the nasal pyramid is the tip. The lateral surfaces are called wings and are clearly separated from the rest of the face by nasolabial folds. Thanks to the wings and the nasal septum, such a clinical structure as the nasal passages or nostrils is formed.
The structure of the external nose
The outer nose includes three parts
Bone frame
Its formation occurs due to the participation of the frontal and two nasal bones. The nasal bones on both sides are limited by processes extending from the upper jaw. The lower part of the nasal bones participates in the formation of the pyriform opening, which is necessary for attaching the external nose.
Cartilaginous part
Lateral cartilages are necessary for the formation of the lateral nasal walls. If you go from top to bottom, you will notice the junction of the lateral cartilages with the large cartilages. The variability of small cartilages is very high, since they are located next to the nasolabial fold and can vary from person to person in number and shape.
The nasal septum is formed by quadrangular cartilage. The clinical significance of cartilage is not only in hiding the inside of the nose, that is, organizing a cosmetic effect, but also in the fact that due to changes in the quadrangular cartilage, a diagnosis of deviated nasal septum may appear.
Soft tissues of the nose
A person does not experience a strong need for the functioning of the muscles surrounding the nose. Basically, muscles of this type perform facial functions, helping the process of identifying odors or expressing an emotional state.
The skin is closely adjacent to the tissues surrounding it, and also contains many different functional elements: glands that secrete sebum, sweat, hair follicles.
The hair that blocks the entrance to the nasal cavities performs a hygienic function, serving as additional air filters. Hair growth causes the formation of a nasal threshold.
After the nasal threshold there is a formation called the intermediate belt. It is tightly connected to the perichondral part of the nasal septum, and when deepened into the nasal cavity it transforms into the mucous membrane.
To correct a deviated nasal septum, an incision is made exactly in the place where the intermediate belt is tightly connected to the perichondrium.
Circulation
The facial and orbital arteries provide blood flow to the nose. The veins follow the course of the arterial vessels and are represented by the external and nasofrontal veins. The veins of the nasofrontal region merge in an anastomosis with the veins that provide blood flow to the cranial cavity. This happens due to the angular veins.
Because of this anastomosis, infection can easily spread from the nasal area into the cranial cavities.
The flow of lymph is ensured through the nasal lymphatic vessels, which flow into the facial vessels, and those, in turn, into the submandibular vessels.
The anterior ethmoidal and infraorbital nerves provide sensation to the nose, while the facial nerve controls muscle movement.
The nasal cavity is limited by three formations. This:
- anterior third of the cranial base;
- eye sockets;
- oral cavity.
The nostrils and nasal passages anteriorly limit the nasal cavity, and posteriorly it extends into the upper part of the pharynx. The transition places are called choanae. The nasal cavity is divided by the nasal septum into two approximately equal components. Most often, the nasal septum may deviate slightly to one side, but these changes are not significant.
Structure of the nasal cavity
Each of the two components has 4 walls.
Inner wall
It is created through the participation of the nasal septum and is divided into two sections. The ethmoid bone, or rather its plate, forms the posterosuperior section, and the vomer forms the posteroinferior section.
Outer wall
One of the complex formations. Consists of the nasal bone, the medial surface of the maxillary bone and its frontal process, the lacrimal bone adjacent posteriorly, and the ethmoid bone. The main space of the posterior part of this wall is formed by the participation of the palate bone and the main bone (mainly the internal plate belonging to the pterygoid process).
The bony part of the outer wall serves as the attachment point for the three nasal conchae. The bottom, fornix and shells participate in the formation of a space called the common nasal passage. Thanks to the nasal conchas, three nasal passages are also formed - upper, middle and lower.
The nasopharyngeal passage is the end of the nasal cavity.
Superior and middle turbinates
Nasal turbinates
They are formed due to the participation of the ethmoid bone. The outgrowths of this bone also form the vesicular concha.
The clinical significance of this shell is explained by the fact that its large size can interfere with the normal process of breathing through the nose.
Naturally, breathing becomes difficult on the side where the concha is too large. Its infection must also be taken into account when inflammation develops in the cells of the ethmoid bone.
Lower sink
This is an independent bone that is attached to the crest of the maxillary bone and the palate bone.
The lower nasal passage has in its anterior third the mouth of a canal intended for the outflow of tear fluid.
The turbinates are covered with soft tissues that are very sensitive not only to the atmosphere, but also to inflammation.
The median passage of the nose has passages into most of the paranasal sinuses. The exception is the main sinus. There is also a semilunar fissure, the function of which is to provide communication between the middle meatus and the maxillary sinus.
Top wall
The perforated plate of the ethmoid bone provides the formation of the nasal arch. The holes in the plate give passage to the olfactory nerves into the cavity.
Bottom wall
Blood supply to the nose
The nasal cavity is supplied with blood by the sphenopalatine artery. The same artery gives off several branches to supply blood to the wall located behind. The anterior ethmoidal artery supplies the lateral wall of the nose with blood. The veins of the nasal cavity merge with the facial and ophthalmic veins. The ophthalmic branch has branches going to the brain, which is important in the development of infections.
The deep and superficial network of lymphatic vessels ensure the outflow of lymph from the cavity. The vessels here communicate well with the spaces of the brain, which is important for accounting for infectious diseases and the spread of inflammation.
The mucosa is innervated by the second and third branches of the trigeminal nerve.
Paranasal sinuses
The clinical significance and functional properties of the paranasal sinuses are enormous. They work in close contact with the nasal cavity. If the sinuses are exposed to an infectious disease or inflammation, this leads to complications on important organs located in close proximity to them.
The sinuses are literally dotted with various openings and passages, the presence of which contributes to the rapid development of pathogenic factors and aggravation of the situation in diseases.
Paranasal sinuses
Each sinus can cause infection to spread into the cranial cavity, eye damage and other complications.
Maxillary sinus
It has a pair and is located deep in the bone of the upper jaw. The sizes vary greatly, but the average is 10-12 cm.
The wall inside the sinus is the lateral wall of the nasal cavity. The sinus has an entrance to the cavity, located in the last part of the semilunar fossa. This wall is endowed with a relatively small thickness, and therefore it is often pierced in order to clarify the diagnosis or carry out therapy.
The wall of the upper part of the sinus has the smallest thickness. The posterior sections of this wall may not have a bone base at all, making do with cartilage tissue and many crevices of bone tissue. The thickness of this wall is penetrated by the canal of the inferior orbital nerve. The infraorbital foramen opens this canal.
The canal does not always exist, but this does not play any role, since if it is absent, then the nerve passes through the sinus mucosa. The clinical significance of this structure is that the risk of developing complications inside the skull or inside the orbit increases if a pathogenic factor affects this sinus.
From below, the wall represents the sockets of the most posterior teeth. Most often, the roots of the tooth are separated from the sinus by only a small layer of soft tissue, which is a common cause of inflammation if the condition of the teeth is not monitored.
Frontal sinus
It has a pair, is located deep in the forehead bone, in the center between the scales and the plates of part of the eye sockets. The sinuses can be delimited using a thin bone plate, and not always equally. It is possible that the plate may shift to one side. There may be holes in the plate that provide communication between the two sinuses.
The size of these sinuses is variable - they may be absent altogether, or they may have a huge distribution throughout the frontal scales and the base of the skull.
The wall in front is where the nerve of the eye exits. The exit is provided by the presence of a notch above the orbit. The notch cuts the entire upper part of the orbit of the eye. In this place, it is customary to perform a sinus opening and trephine puncture.
Frontal sinuses
The wall below is the smallest in thickness, which is why infection can quickly spread from the sinus to the eye orbit.
The brain wall provides separation of the brain itself, namely the lobes of the forehead from the sinuses. It also represents a point of entry for infection.
The canal passing in the frontonasal region provides interaction between the frontal sinus and the nasal cavity. The anterior cells of the ethmoid labyrinth, which have close contact with this sinus, often intercept inflammation or infection through it. Also, through this connection, tumor processes spread in both directions.
Lattice Maze
It is cells separated by thin partitions. The average number is 6-8, but it can be more or less. The cells are located in the ethmoid bone, which is symmetrical and unpaired.
The clinical significance of the ethmoidal labyrinth is explained by its close location to important organs. Also, the labyrinth may be adjacent to the deep parts that form the facial skeleton. The cells located in the back of the labyrinth are in close contact with the canal in which the nerve of the visual analyzer runs. Clinical diversity appears to be an option when the cells serve as the direct path of the canal.
Diseases affecting the labyrinth are accompanied by a variety of pains, varying in location and intensity. This is explained by the peculiarities of the innervation of the labyrinth, which is provided by a branch of the orbital nerve, called the nasociliary. The cribriform plate also provides passage for the nerves necessary for the functioning of the sense of smell. That is why, if there is swelling or inflammation in this area, olfactory disturbances are possible.
Lattice Maze
Main sinus
The sphenoid bone, with its body, provides the location of this sinus directly behind the ethmoid labyrinth. The choanae and the nasopharynx will be located on top.
In this sinus there is a septum that has a sagittal (vertical, dividing the object into right and left parts) location. It most often divides the sinus into two unequal lobes and does not allow them to communicate with each other.
The wall in front consists of a pair of formations: the ethmoidal and nasal. The first occurs in the region of the labyrinth cells located posteriorly. The wall is characterized by a very small thickness and, thanks to its smooth transition, almost merges with the wall below. In both parts of the sinus there are small round passages that allow the sphenoid sinus to communicate with the nasopharynx.
The wall at the back has a frontal position. The larger the size of the sinus, the thinner this septum, which increases the likelihood of injury during surgical interventions in this area.
The wall on top is the bottom region of the sella turcica, which is the location of the pituitary gland and the chiasm of the nerve that provides vision. Often, if the inflammatory process affects the main sinus, it spreads to the optic chiasm.
The wall below is the vault of the nasopharynx.
The walls on the sides of the sinus are closely adjacent to the bundles of nerves and vessels that are located on the side of the sella turcica.
In general, infection of the main sinus can be called one of the most dangerous. The sinus is closely adjacent to many brain structures, for example, the pituitary gland, subarachnoid and arachnoid membranes, which simplifies the spread of the process to the brain and can be fatal.
Pterygopalatine fossa
Located behind the tubercle of the mandibular bone. A large number of nerve fibers pass through it, so the significance of this fossa in a clinical sense is difficult to exaggerate. Inflammation of the nerves passing through this fossa is associated with a large number of symptoms in neurology.
It turns out that the nose and the formations that are closely connected with it are a very complex anatomical structure. Treatment of diseases affecting the nasal systems requires maximum care and caution from the doctor due to the close location of the brain. The main task of the patient is not to let the disease progress, bringing it to a dangerous limit, and to promptly seek help from a doctor.
10-01-2013, 20:57
Description
External nose consists of a cartilaginous (mobile) part and a bone skeleton formed in the upper part by the nasal processes (processes nasales) of the frontal bone and nasal bones, to which the frontal processes of the maxillary bone adjoin below and to the sides.The cartilaginous part is composed of a number of cartilages (paired triangular and alar cartilages, as well as sesamoids, varying in both number and size).
Triangular lateral cartilage(cartilago triangularis) the medial side is located parallel to the bridge of the nose; the lower part merges with the cartilaginous part of the nasal septum. The posterior part of the triangular cartilage reaches the lower edge of the nasal bone, and its lower side borders the upper edge of the alar cartilage.
Wing cartilages(cartilagines alares) of both sides, touching along the midline, form the tip of the nose and take part in the formation of the solid base of the wing of the nose, limiting the nasal openings - nostrils (nares) of each side.
The cartilages are connected to each other by fibrous tissue.
The muscles of the external nose are located in the area of the nasal wings and serve to expand the entrance to the nose (mm. levatores alae nasi) and narrow the nasal openings (mm. compressores nasi et depressores alae nasi).
Blood supply to the external nose carried out through the branches of the external and internal maxillary arteries, namely a. dorsalis nasi (from a. ophthalmica - system of internal carotid artery), anastomosing with a. angularis, branch a. maxillaris externa (external carotid artery system), as well as from a. septi mobilis nasi (from a. labialis).
Blood from the veins of the external nose flows to the anterior facial vein. The venous system of the external nose is closely connected with the venous system of the nasal mucosa.
The lymphatic system is connected to the submandibular and anterior parotid glands.
Motor innervation of the external nose carried out by branches of the facial nerve, and sensory fibers come from the ethmoidal nerve (from the n. ophthalmicus I branch of the trigeminal nerve) and the inferior orbital (from the n. maxillaris - II branch of the trigeminal nerve) nerve to the cartilaginous part of the external nose and from the upper and lower orbital nerves to the bony skeleton of the nose.
The nasal cavity is located between the eye sockets, the oral cavity and the anterior cranial fossa (Fig. 1).
Rice. 1. Bone skeleton of the nasal cavity; anterior sections. Front view (according to V.P. Vorobyov).
In front, it communicates through the anterior nasal openings with the outer surface of the face, and behind, through the choanae, with the upper part of the pharynx (nasopharynx). The nasal septum divides the nasal cavity into two non-communicating halves (right and left), each of which has an external opening and choana (Fig. 2).
Rice. 2. Bone skeleton of the nasal cavity from behind (frontal cut through the anterior sections of the zygomatic arches).
Vestibule of the nasal cavity(vestibulum nasi). The skin covering the external nose is tucked inward and retains its properties throughout the entire vestibule; it is covered with a significant number of hairs (vibrissae), especially in older men. Hairs are, to a certain extent, a filter that traps large dust particles, but in some cases they can become a source of development of boils, since staphylococci nest in the hair follicles.
The entrance to the bony part of the nose (apertura piriformis) is pear-shaped, the edges of which are formed by the frontal processes of the upper jaw and the lower edges of both nasal bones.
The nasal cavity itself, being a continuation of the canal of the vestibule of the nose, bounded by the bony skeleton and covered by mucous membrane. In addition to the nasopharynx, it communicates with the paranasal cavities and through the foramen sphenopalatinum - with the pterygopalatine fossa, as well as with the nasolacrimal canal and through it with the conjunctival sac.
The canal of each half of the nasal cavity is limited by four walls: internal (common to both halves), external, upper (roof) and lower (bottom).
The inner, or medial, wall is the nasal septum. It consists of a perpendicular plate hanging downwards (lamina perpendicularis ossis ethmoidalis; Fig. 1, e, Fig. 2), supplemented downwards and posteriorly by a vomer (vomer; Fig. 3, b),
Rice. 3. Bone skeleton of the nasal cavity, posterior sections. Frontal cut through the temporal processes of the zygomatic bones (according to V.P. Vorobyov). a - choanae; b - opener; c - vomer wings; d - horizontal plate of the palatine bone; d - vertical plate of the palatine bone; e - crista turbinalis; g - maxillary sinus; h - mastoid process; and - zygomatic process of the temporal bone (sawed off); k - foramen sphenopalatinum; l - cells of the ethmoid labyrinth; m - opening of the main sinus; k - optic nerve opening.
and anteriorly - by quadrangular cartilage, which at the border of the nasal cavity and the vestibule passes into the skin part of the septum. The last two sections make up the movable part of the nasal septum, as opposed to the fixed bony part (posterior part of the septum). The outer wall of the nasal cavity, common with the inner wall of the maxillary sinus, is the most complex in its anatomical structure. Familiarity with the topographic anatomy of the lateral wall of the nasal cavity is mandatory not only for the rhinologist, but also for the ophthalmologist, since the nasolacrimal canal passes here.
Outer wall(Fig. 4 and 5)
Rice. 4. The outer wall of the skeleton of the nasal cavity (according to V.P. Vorobyov). a - frontal sinus; b - nasal bone; c - spina frontalis; g - lacrimal bone; d - inferior nasal concha; e - canalis incisivus; g - alveolar process; h - crista galli; and - palatine process of the maxillary bone; k - lower nasal passage; l-middle nasal passage; m - upper nasal passage; n - middle turbinate; o - superior nasal concha; n - main cavity; p - foramen sphenopalatinura; c - opening of the main sinus.
Rice. 5. The outer wall of the skeleton of the nasal cavity (after removal of the upper, middle and part of the lower nasal concha) (according to V.P. Vorobyov). a - frontal sinus; b - a probe from the frontal cavity protrudes into the lumen of the semilunar fissure; c - semicanalis obliquus (hiatus semilunaris); g-proc. uncinatus ossis ethmoidalis; d - bulla ethmoidalis; e - os lacrimale; g - inferior nasal concha; h - probe in the nasolacrimal canal; and - canalis incisivus; j - palatine process of the maxillary bone; l - maxillary sinus; m - body of the main bone; k - sella turcica; o - optic nerve opening; n - main sinus; p - opening of the posterior cells of the ethmoidal labyrinth; c - sieve-shaped, or perforated, plate; t - opening of the anterior cells of the ethmoidal labyrinth; y - middle turbinate (cut off); f - superior turbinate (cut off); x - main cavity opening.
formed by the nasal bone, the nasal (medial) surface of the body of the maxillary bone with its frontal process, the lacrimal bone, the ethmoid bone (with its superior and middle nasal conchae, bulla ethmoidalis et processus uncinatus), the vertical plate of the palatine bone and the pterygoid process of the sphenoid bone, which participates in the formation of the choana. In addition to the superior and middle turbinates (Fig. 4, o and n), which belong to the ethmoid bone, on the outer wall of the nose there is an inferior nasal concha (Fig. 4, e), which is an independent bone (os turbinale). It is attached with its upper edge in front to the linear protrusion (crista turbinalis; Fig. 3, f) on the frontal process of the upper jaw, and behind - to the crest of the palatine bone. The outlet of the nasolacrimal canal opens under the arch of the inferior concha (Fig. 5, h).
When one of the anterior cells of the ethmoidal labyrinth enters the anterior end of the middle shell, this shell takes the form of a swollen bubble (concha bullosa).
According to the three shells, three nasal passages are distinguished:
- inferior (the space between the inferior turbinate and the bottom of the nasal cavity),
- middle (between the middle and inferior turbinates)
- and upper (above the middle shell) (Fig. 4, j, l, m).
The area bounded on the medial side by the nasal septum, and on the external side by the conchae, is called the common nasal passage (meatus nasi communis). It is usually divided into two sections: upper (regio olfactoria) and lower (regio respiratoria).
In clinical and diagnostic terms, the most important part of the outer wall of the nasal cavity is middle nasal passage(Fig. 4, l), into which the excretory openings of the maxillary and frontal cavities, as well as the anterior and partly middle cells of the ethmoidal labyrinth open.
On a macerated skull, this area corresponds to the hiatus maxillaris, significantly narrowed, since it is covered with bone formations (uncinate process - proc. uncinatus of the ethmoid bone, processes of the inferior turbinate). Places devoid of bone are covered with fontanelles (fontanelles), i.e., a duplication of fused layers of the mucous membrane of the nasal and maxillary cavities. There are usually two fontanelles, of which the posterior one is bounded by the ethmoidal process, the posterior end of the uncinate process and the perpendicular plate of the palatine bone, and the anterior one is located between the uncinate process, the inferior concha and its ethmoidal process.
On a fresh specimen after removal of the middle turbinate or part of it, a semilunar or crescent-shaped fissure is visible (hiatus semilunaris; Fig. 5, c), first described by N. I. Pirogov and called semicanalis obliquus.
It is limited in front and below by the above-mentioned uncinate process of the ethmoid bone (Fig. 5, d) with bone protrusions extending from it downwards and posteriorly, and behind and above - by a convexity (bone bubble) of one of the cells of the ethmoid labyrinth (bulla ethmoidalis; Fig. 5 , d). Small gaps between the individual protrusions of the uncinate process lead into the maxillary sinus, and in a fresh specimen they are covered with a duplication of the mucous membrane. Only the posterior part of the semilunar fissure remains free from the mucous membrane and is a permanent opening of the maxillary sinus (ostium maxillare). In the posterior part of the semilunar fissure there is an expansion that narrows towards the maxillary cavity in the form of a funnel (infundibulum), at the bottom of which there is an outlet of the maxillary sinus (ostium maxillare).
Along with a permanent hole, it is often possible to see accessory opening of the maxillary sinus(ostium maxillare accessorium), also opening into the middle meatus.
The outlet of the frontal cavity opens into the anterior-superior part of the semilunar fissure (ductus naso-frontalis; Fig. 5, b).
The anterior and part of the posterior cells of the ethmoidal labyrinth usually open on the anterior and posterior walls of the semilunar fissure, as well as in the angle between the bulla ethmoidalis and the middle turbinate. Sometimes, near the outlet of the frontal sinus, one of the anterior cells of the ethmoidal labyrinth opens.
We will dwell on the question of options for the location of the excretory ducts of the accessory cavities in the middle meatus when we talk about the anatomy of the sinuses.
At empyema of the anterior sinuses, namely the maxillary and frontal sinuses, as well as the anterior and part of the middle cells of the ethmoidal labyrinth, pus flows through the above excretory ducts and accumulates in the recess of the semilunar fissure. Using rhinoscopy, in such cases it is possible to detect pus in the middle nasal meatus.
The posterior and part of the middle cells of the ethmoid labyrinth, as well as the main cavity, open with their excretory openings into the upper nasal passage and into the recess located between the surface of the body of the sphenoid bone and the superior nasal concha (recessus spheno-ethmoidalis). The presence of pus detected during posterior rhinoscopy always indicates a purulent process in the posterior paranasal cavities.
The upper wall of the nasal cavity is mainly formed by sieve-shaped or perforated plate(lamina cribrosa), supplemented in front by the frontal and nasal bones, the frontal processes of the upper jaw, and in the back by the anterior wall of the main cavity. The sieve, or perforated, plate (Fig. 5, c) is pierced by a large number of holes through which the fila olfactoria pass; the fibers of the olfactory nerve penetrate the olfactory bulb (bulbus olfactorius) of the corresponding half of the nose, which lies on the cranial surface of the sieve plate, lateral to the cockscomb. Through the openings of the cribriform plate, the anterior ethmoidal artery and the veins and nerve of the same name also penetrate from the nose into the cranial cavity.
Lower wall of the nasal cavity formed by the palatine processes of the upper jaw (Fig. 2), supplemented posteriorly by horizontal plates of the palatine bone (Fig. 3, d), and is concave in the frontal and sagittal plane.
The mucous membrane covering the respiratory region of the nose, from the vestibule to the olfactory region, is covered with stratified columnar ciliated epithelium. The mucous membrane of the olfactory region, which extends to the surface of the superior concha, the upper part of the middle concha and the part of the nasal septum corresponding to these areas, is lined with a special olfactory epithelium, which consists of cells of two genera: olfactory and support. Olfactory cells are peripheral nerve receptors of the olfactory analyzer. The central processes of the olfactory cells, extending from the bottom of the flask, form olfactory fibers (fila olfactoria) in the openings of the sieve plate, through which they penetrate, heading towards the olfactory nerve.
The arteries of the nasal cavity arise from the common and external carotid arteries.
Arterial nutrition provided by a. sphenopalatina from a. maxillaris interna - VIII branch of the external carotid artery, entering from the fossa pterygopalatina into the nasal cavity through the foramen sphenopalatinum and breaking up here into aa. nasales posteriores with branches (a. nasalis posterior lateralis et a. nasalis posterior septi nasi) and on a. nasopalatina. Through these branches, the lower, middle and upper turbinates, their corresponding nasal passages, as well as part of the nasal septum are supplied with arterial blood.
The upper part of the outer wall of the nose and part of the septum receive blood from the anterior and posterior ethmoidal arteries, which are branches of a. ophthalmica.
The veins of the nasal cavity follow the course of the arteries of the same name. A large number of venous plexuses connect the veins of the nasal cavity with the veins of the orbit, skull, face and pharynx.
In the pathology of inflammatory diseases of the orbit, the connection between the anterior and posterior ethmoidal veins and the orbital veins is of great importance, and through the orbital veins there is a connection with the cavernous sinus. One of the branches of the anterior ethmoid vein, penetrating through the cribriform plate into the cranial cavity, connects the nasal cavity, and with it the orbit, with the venous plexus of the pia mater.
The lymphatic system of the nasal cavity consists of superficial and deep layers of vessels that are connected to the subdural and subarachnoid space of the meninges.
Sensory innervation of the nasal cavity carried out by the second branch of the trigeminal nerve, as well as due to the ganglion sphenopalatinum.
From the first branch of the trigeminal nerve (n. ophthalmicus and its branches n. nasociliaris) the nn are directed to the nasal cavity. ethmoidales anterior et posterior, as well as rr. nasales mediales et laterales.
From the second branch of the trigeminal nerve (n. maxillaris) branches n. extend to the nasal cavity. infraorbitalis - rr. nasales externi et interni.
From the olfactory epithelium of the mucous membrane of the nasal cavity, nerve fibers (fila olfactoria) of each side go through the holes in the sieve plate to the olfactory bulb and further, as part of the tractus olfactorius et trigonum olfactorium, forming a common trunk, they reach first the subcortical centers of smell in the gray matter, and then the brain cortex (gyrum hippocampus et gyrus subcallosus).
The connection between the innervation of the nasal cavity and the eye is provided through n. nasociliaris et ganglion nasociliare.
Sympathetic innervation stands in connection with the superior cervical sympathetic ganglion. Sympathetic fibers originating from the plexus caroticus are directed to the gasser node, and from there, as part of n. ophthalmicus and n. maxillaris (I and II branches of the trigeminal nerve) penetrate the nasal cavity, paranasal sinuses and orbit. The bulk of the fibers are composed of n. maxillaris through the pterygopalatine ganglion (ganglion spheno-palatinum), in which they are not interrupted, and then branch in the nasal cavity and paranasal sinuses. A smaller part of the fibers (anterior and posterior ethmoidal nerves - branches of n. ophthalmicus) penetrates the nose through the corresponding openings on the inner wall of the orbit.
Parasympathetic fibers, starting in the corresponding centers of the medulla oblongata, are part of the facial nerve and along n. petrosus major reach the pterygopalatine ganglion, where they are interrupted, and then, in the form of postganglionic fibers, reach the nasal cavity and orbit.
From the above data it follows that there is a close nervous connection between the nasal cavity, its paranasal sinuses and the orbit, which is carried out due to trigeminal sympathetic and parasympathetic innervation through the ganglion cervicalis superior, ganglion Gasseri, ganglion, ciliaris (in the orbit) and ganglion sphenopalatinum (in nose).