Nasal cavity

The nasal cavity (cavum nasi) is divided by the nasal septum into right and left halves. In front of the face, the nasal cavity opens through the nostrils, and behind it communicates with the nasopharynx through the choanae. The nasal septum (septum nasi) is divided into membranous, cartilaginous and bony parts. The membranous and cartilaginous parts are movable. Each half of the nasal cavity is divided into an anterior part - the vestibule - and the nasal cavity itself, located at the back. The vestibule of the nasal cavity (vestibulum nasi) is limited at the top by a small elevation - the nasal threshold (limen nasi), formed by the upper edge of the large cartilage of the ala of the nose. On the lateral walls of the nasal cavity there are three elevations protruding into the nasal cavity - the nasal turbinates. Under the upper, middle and lower turbinates there are depressions: the upper, middle and lower nasal passages. The upper nasal passage is present only in the posterior parts of the nasal cavity. Between the nasal septum and the medial surface of the nasal conchae on each side is the common nasal meatus, which looks like a narrow vertical slit oriented in the sagittal plane. The sphenoid sinus and the posterior cells of the ethmoid bone open into the superior nasal meatus; the frontal sinus (through the ethmoid infundibulum), the maxillary sinus (through the semilunar cleft), and the anterior and middle cells of the ethmoid bone open into the middle nasal meatus. The middle nasal meatus communicates with the pterygopalatine fossa via the sphenopalatine foramen; the inferior nasal meatus communicates with the orbit (through the nasolacrimal duct).

The mucous membrane of the vestibule of the nasal cavity is lined with flat epithelium, which is a continuation of the skin. Sebaceous glands and the roots of bristle hairs are located in the connective tissue layer under the epithelium. The nasal cavity is divided into olfactory and respiratory regions. The olfactory region (regio olfactoria) occupies the superior nasal turbinates, the upper part of the middle nasal turbinates and the upper part of the nasal septum. The olfactory and respiratory regions are lined with ciliated pseudostratified epithelium. The epithelial cover of the olfactory region contains neurosensory bipolar cells. The epithelium of the rest of the mucous membrane of the nasal cavity (respiratory region, regio respiratoria) contains a large number of goblet cells that secrete mucus. Mucus covers the epithelium and humidifies the air. Due to the movement of the cilia, mucus with foreign particles is removed to the outside. The proper plate of the mucous membrane is thin, contains a significant number of elastic fibers, as well as numerous serous and mucous glands. In the thickness of the proper plate of the mucous membrane there are many blood vessels, especially thin-walled veins, the presence of which helps warm the inhaled air. The muscular plate of the mucous membrane is poorly developed, the submucosa is thin, contains vascular and nerve plexuses, lymphoid tissue, mast and other cells, glands.

Air from the nasal cavity through the choanae enters the nasal, then the oral part of the pharynx, then the larynx. The structure of the pharynx is described above.

Roentgen anatomy of the nasal cavity. Roentgenography of the nasal cavity is performed in the nasomental and nasofrontal projections. The nasal conchae, nasal passages, nasal septum, and paranasal sinuses are visible on the X-ray image.

Innervation of the mucous membrane of the nasal cavity: sensory (anterior part) - anterior ethmoidal nerve from the nasociliary nerve; posterior part of the lateral wall of the nasal cavity and nasal septum - nasopalatine nerve and posterior nasal branches (from the maxillary nerve). The glands of the mucous membrane receive secretory innervation from the pterygopalatine ganglion.

Blood supply: sphenopalatine artery (from the maxillary artery), anterior and posterior ethmoidal arteries (from the ophthalmic artery). Venous drainage: sphenopalatine vein (tributary of the pterygoid plexus).

Lymph drainage: to the submandibular and submental lymph nodes.

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Age-related features of the nasal cavity

In a newborn, the nasal cavity is low (its height is 17.5 mm) and narrow. The nasal turbinates are relatively thick. The superior nasal passage is absent, the middle and lower ones are poorly developed. The nasal turbinates do not reach the nasal septum, the common nasal passage remains free, and the newborn breathes through it, the choanae are low. By 6 months, the height of the nasal cavity increases to 22 mm and the middle nasal passage is formed, by 2 years - the lower, after 2 years - the upper. By 10 years, the nasal cavity increases in length by 1.5 times, and by 20 years - by 2 times. By this age, its width increases. Of the paranasal sinuses, a newborn has only a poorly developed maxillary sinus. The remaining sinuses begin to form after birth. The frontal sinus appears in the 2nd year of life, the sphenoid sinus - by 3 years, the ethmoid cells - by 3-6 years. By the age of 8-9 years, the maxillary sinus occupies almost the entire body of the bone. The opening through which the maxillary sinus communicates with the nasal cavity is oval in a 2-year-old child, and by

7 years - round. The frontal sinus by the age of 5 has the size of a pea. Narrowing downwards, it communicates with the middle nasal passage through the ethmoid funnel. The size of the sphenoid sinus in a child aged 6-8 years reaches 2-3 mm. The sinuses of the ethmoid bone at the age of 7 are tightly adjacent to each other; by the age of 14, their structure is similar to the ethmoid cells of an adult.

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