Human nose anatomy

The human nose is a sensory and respiratory organ that performs a number of important functions related to providing tissues with oxygen, forming speech, recognizing odors and protecting the body from negative external factors. Next, we will take a closer look at the structure of the human nose and answer the question of what a nose is for.

General structure and function

It is a unique part of the human body. In nature, there are no living beings with such a nose structure. Even the closest relatives of people - monkeys - are very different both in appearance and internal structure, and in the principles of its work. Many scientists associate the way the nose is arranged and the peculiarities of the development of the sense organ with upright posture and the development of speech.

The external nose can vary quite a lot depending on gender, race, age, individual characteristics. As a rule, it is smaller in women, but wider than in men.

In groups of European peoples, leptorinia (a narrow and high sense organ) is more often observed, in representatives of the Negroid race, indigenous Australians and Melanesians, hamerinia (wider). However, the internal anatomy and physiology of the nose is the same in all people.

The human nose is the initial section of the upper respiratory system. It consists of three main segments:

• nasal cavity;
• outdoor area;
• accessory voids communicating with the cavity through thin channels.

The most important functions of the nose, which provide an answer to the question of why a person needs a nose:

• Respiratory. Providing body tissues with the necessary amount of oxygen. The peculiarity of the structure of the human nose is such that only through it a sufficient amount of oxygen is supplied for the full functioning of the main systems of the body. It has been proven that when breathing through the mouth, only 78% of the required volume of the air mixture is delivered.
• Thermoregulatory. Heats the cold air flow entering the respiratory system by separating it, creating turbulent eddies and rapid heat transfer from numerous blood vessels. This process avoids hypothermia of the pharynx and brain, and also ensures the preservation of heated air.
• Moisturizing. The dry stream is saturated with moisture by evaporation of secretions from the tissues of the ciliated epithelium, which can take up to 0.5 liters of moisture per day under normal conditions, and up to 2 liters in case of inflammatory processes.
• Protective. Filtration of incoming air to remove germs and dust. The hairs trap larger particles, small suspended particles are bound by mucus and subsequently evacuated. Enzymes (mucin, lysozyme) contained in the secretion reduce the number of microorganisms in the inhaled air by 10 times. NSWhen the mucous membrane is irritated, the cavities are cleared by sneezing and profuse lacrimation.
• Resonator. Participation in the formation of speech, creating a resonance of the voice, giving it individual characteristics, timbre, tonality and sonority. If the nasal anatomy is disturbed, the voice becomes nasal.
• Olfactory. Recognizing odors using the olfactory cells. Promotes the secretion of saliva and gastric juice. It gradually loses its vital importance for people.

The structure of the outer part

The outer nose is located on the outer part of the face, is clearly visible and looks like a triangular irregular pyramid. Its shape is created by bone, soft and cartilage tissue.

The bony section (back, root) is formed by paired nasal bones, which are connected to the nasal processes of the frontal bone and the frontal processes of the upper jaw adjacent to the side. It creates an immobile bone skeleton, to which a mobile cartilaginous section is attached, the components of which are:

• Paired lateral cartilage (cartilago nasi lateralis) has the shape of a triangle, takes part in the creation of the wing and back. Its posterior edge adjoins the beginning of the nasal bone (a hump is often formed there), the inner edge grows together with the cartilage of the same name on the opposite side, and the lower edge - to the nasal septum.
• Paired large wing cartilage (cartilago alaris major), surrounds the entrance to the nostrils. It is subdivided into lateral (crus laterale) and medial (crus mediale) legs. The medial ones divide the nostrils and form the tip of the nose, the lateral ones are longer and wider, form the structure of the nasal wings and are supplemented by another 2-3 small cartilages in the posterior parts of the wings.

All cartilages are connected to bones and to each other by fibrous tissue and are covered by the perichondrium.

The outer nose has mimic muscles located in the area of ​​the wings, with the help of which people can narrow and widen the nostrils, raise and lower the tip of the nose. From above it is covered with skin, which contains many sebaceous glands and hairs, nerve endings and capillaries. Blood supply is carried out from the systems of the internal and external carotid arteries through the external and internal jaw arteries. The lymphatic system is focused on the submandibular and parotid lymph nodes. Innervation - from the facial and 2 and 3 branches of the trigeminal nerve.

Due to its prominent location, the external nose is most often subjected to correction by plastic surgeons, to whom people turn in the hope of getting the desired result.

Correction can be performed to align the hump at the junction of the bone and cartilage, however, the main object of rhinoplasty is the tip of the nose. An operation in clinics can be performed both according to medical requirements and at the request of a person.

Common causes of rhinoplasty:

• change in the shape of the apex of the sense organ;
• decrease in the size of the nostrils;
• birth defects and consequences of trauma;
• deviated septum and asymmetrical tip of the nose;
• violation of nasal breathing due to deformation.

You can also correct the tip of the nose without surgery using special Aptos threads or fillers based on hyaluronic acid, which are injected subcutaneously.

Anatomy of the nasal cavity

The nasal cavity is the initial segment of the upper respiratory tract. Anatomically located between the oral cavity, the anterior cranial fossa and the orbits. In the front part it goes to the surface of the face through the nostrils, in the back - to the pharyngeal region through the choanae. Its inner walls are formed by bones, it is separated from the mouth by a hard and soft palate, it is divided into three segments:

• the threshold;
• respiratory area;
• olfactory area.

The cavity opens with a vestibule located next to the nostrils. From the inside, the vestibule is covered with a strip of skin 4-5 mm wide, equipped with numerous hairs (especially in older men). Hair is a barrier to dust, but often cause boils due to the presence of staphylococci in the bulbs.

The inner nose is an organ divided into two symmetrical halves by a bony and cartilaginous plate (septum), which is often curved (especially in men). Such a curvature is within normal limits, if it does not interfere with normal breathing, otherwise it is necessary to correct it surgically.

Each half has four walls:

• the medial (internal) is the septum;
• lateral (external) - the most difficult. It consists of a number of bones (palatine, nasal, lacrimal, maxillary);
• upper - sigmoid plate of the ethmoid bone with holes for the olfactory nerve;
• lower - part of the upper jaw and the process of the palatine bone.

On the bony component of the outer wall, on each side, there are three shells: the upper, middle (on the ethmoid bone) and the lower (independent bone). In accordance with the scheme of the shells, nasal passages are also distinguished:

• The lower one is between the bottom and the lower shell. Here is the outlet of the lacrimal canal, through which the ocular discharge flows into the cavity.
• The middle one is between the lower and middle shells. In the area of ​​the lunar gap, first described by M.I. Pirogov, the outlet openings of most of the accessory chambers open into it;
• The upper one - between the middle and upper shells, is located behind.

In addition, there is a common passage - a narrow gap between the free edges of all shells and the septum. The passages are long and winding.

The respiratory area is lined with a mucous membrane consisting of secretory goblet cells. Mucus has antiseptic properties and suppresses the activity of microbes; in the presence of a large number of pathogens, the volume of secreted secretions also increases. From above, the mucous membrane is covered with a cylindrical multi-row ciliated epithelium with miniature cilia. The cilia are constantly moving (flickering), in the direction of the choanas and further the nasopharynx, which allows you to remove mucus with associated bacteria and foreign particles. If there is too much mucus and the cilia do not have time to evacuate it, then a runny nose (rhinitis) develops.

Under the mucous membrane there is a tissue permeated with a plexus of blood vessels. This makes it possible, by instantaneous swelling of the mucous membrane and narrowing of the passages, to protect the sensory organ from irritants (chemical, physical and psychogenic).

The olfactory area is located at the top. It is lined with epithelium, which contains receptor cells responsible for the sense of smell. The cells are spindle-shaped. At one end, they emerge on the surface of the shell in bubbles with cilia, and at the other end they pass into the nerve fiber. The fibers are woven into bundles to form the olfactory nerves. Aromatic substances through mucus interact with receptors, excite the nerve endings, after which the signal goes to the brain, where the smells differ. A few molecules of the substance are enough to excite the receptors. A person is able to smell up to 10 thousand smells.

The structure of the paranasal sinuses

The anatomy of the human nose is complex and includes not only the sensory organ itself, but also the voids (sinuses) that surround it, and with which it is in close interaction, connecting through channels (anastomosis). The sinus system includes:

• wedge-shaped (main);
• maxillary (maxillary);
• frontal (frontal);
• lattice maze cells.

The maxillary sinuses are the largest of all, their volume can reach 30 cubic centimeters. The chambers are located on the upper jaw between the teeth and the lower part of the eye sockets, they consist of five walls:

• The nasal plate is a bone plate that smoothly passes into the mucous membrane. The hole connecting to the nasal passage is located in its angular part. With a difficult outflow of secretions, an inflammatory process develops, called sinusitis.
• Facial is palpable, the densest, covered with cheek tissues. Located in the canine fossa of the jaw.
• The orbital is the thinnest, it has a plexus of veins and an infraorbital nerve, through which infection can pass to the eyes and the brain membrane.
• The posterior one goes to the maxillary nerve and maxillary artery, as well as the pterygopalatine node.
• The lower one is adjacent to the oral cavity, the roots of the teeth can protrude into it.

The frontal sinuses are located in the thickness of the frontal bone, between its anterior and posterior walls.

In newborns, it is absent, begins to form from the age of 3, the process usually continues until the end of a person's sexual development. About 5% of people have no frontal voids at all. The sinuses are composed of 4 walls:

• Orbital. Adjacent to the orbit, it has a long narrow connecting channel, with edema of which frontitis develops.
• Facial - a part of the frontal bone up to 8 mm thick.
• The cerebral is adjacent to the dura mater and the anterior cranial fossa.
• The inner part divides the void into two chambers, often unequal.

The sphenoid sinus is located deep in the thickness of the bone of the same name, it is divided by a septum into two parts of different sizes, each of which independently connects to the upper passage.

As well as frontal voids, it is formed in children from the age of three and develops up to 25 years. This sinus is in contact with the cranial base, carotid arteries, optic nerves and pituitary gland, which can lead to serious inflammation. However, diseases of the sphenoid sinus are very rare.

Ethmoid sinus (labyrinth) consists of interconnecting individual ethmoid bone cells, arranged in a row, 5-15 pieces on each side. Depending on the depth of the location, internal ones are distinguished (they go into the upper course), middle and front ones (connected to the middle course).