Human Anatomy, Part 1 - K. A. Dyubenko, A. K. Kolomiysev, Yu. B. Chaykovsky 2002

Special Section
Axial skeleton, sceleton axiale — The Skull as a Whole
Nasal cavity

The Nasal Cavity, cavum nasi, is a sagittal passage extending from the piriform aperture to the choanae, and is divided by the nasal septum into two halves. The nasal cavity is bounded by five walls: superior, inferior, lateral, and medial.

The superior wall is formed by the Frontal bone, the inner surface of the nasal bones, the lamina cribrosa of the Ethmoid bone, and the body of the Sphenoid bone.

The inferior wall is formed by the bony palate, palatinum osseum, which comprises the palatine process of the Maxilla and the horizontal plate of the Palatine bone.

The lateral wall is formed by the body of the maxilla, the Nasal bone, the frontal process of the maxilla, the Lacrimal bone, the labyrinth of the ethmoid bone, the Inferior nasal concha, the perpendicular plate of the palatine bone, and the medial plate of the pterygoid process.

The medial wall, or nasal septum, septum nasi osseum, divides the nasal cavity into two halves. It is formed by the perpendicular plate of the ethmoid bone and the Vomer (Fig. 54); superiorly by the nasal spine of the frontal bone, spina nasalis; posteriorly by the sphenoidal crest, crista sphenoidalis, of the sphenoid bone; and inferiorly by the nasal crest, crista nasales, of the maxilla and the palatine bone. The nasal cavity opens anteriorly through the piriform aperture, apertura piriformis, and posteriorly through the choanae. The choanae, choanae, are paired internal openings of the nasal cavity that connect it with the nasal part of the Pharynx.

Class="center">

Fig. 54. Nasal septum, septum nasi osseum (after F. Kiss and J. Szentágothai)

Fig. 55. Lateral wall of the nasal cavity

On the lateral wall of the nasal cavity, there are three nasal conchae: superior, middle, and inferior, concha nasalis superior, media et inferior (Fig. 55). The superior and middle nasal conchae belong to the ethmoid labyrinth, whereas the inferior concha is an independent bone. These conchae bound three nasal meatuses: superior, middle, and inferior, meatus nasalis superior, medius et inferior.

The superior nasal meatus, meatus nasalis superior, runs between the superior and middle nasal conchae. The posterior ethmoidal Cells open into it. Near the posterior end of the superior nasal concha lies the sphenopalatine foramen, foramen sphenopalatinum, which leads into the fossa pterygopalatina. Above the superior nasal concha is the spheno-ethmoidal recess, recessus spheno-ethmoidalis, into which the sphenoidal sinus, sinus sphenoidalis, opens.

The middle nasal meatus, meatus nasalis medius, is located between the middle and inferior nasal conchae. Within it, after removal of the middle concha, the semilunar hiatus, hiatus semilunaris, opens. The posterior-inferior part of the semilunar hiatus features an expansion at the bottom of which is the maxillary hiatus, hiatus maxillaris, leading into the maxillary sinus, sinus maxillaris. In the anterior-superior part of the nasal cavity, the semilunar hiatus expands to form the ethmoidal infundibulum, infundibulum ethmoidale, into which the frontal sinus, sinus frontalis, opens. In addition, the anterior and some middle ethmoidal cells open into the middle nasal meatus and the semilunar hiatus.

The inferior nasal meatus, meatus nasalis inferior, lies between the bony palate and the inferior nasal concha. The nasolacrimal canal, canalis nasolacrimalis, opens into it. In clinical (otolaryngological) practice, puncture of the maxillary sinus is performed through the inferior nasal meatus for diagnostic and therapeutic purposes.

The slit-like space between the posterior Regions of the nasal conchae and the bony nasal septum is called the common nasal meatus, meatus nasi communis. The region of the nasal cavity located posterior to the nasal conchae and the bony nasal septum forms the nasopharyngeal meatus, meatus nasopharyngeus, which opens into the posterior nasal apertures, the choanae.

Buttresses are bone thickenings in specific areas of the cranium interconnected by transverse struts, through which chewing pressure is transmitted to the cranial vault. These buttresses balance the forces generated during mastication, impacts, and jumping. Thinner bony structures, known as weak points, are located between these thickenings. Fractures most commonly occur precisely here under physical stress that does not coincide with the physiological acts of chewing, swallowing, and speech. In clinical practice, fractures are most frequently observed in the neck of the Mandible, the mandibular angle, the maxilla, as well as the Zygomatic bone and its arch. The presence of apertures, fissures, and weak points in the cranial bones determines the lines of these fractures, which is crucial to consider in maxillofacial surgery. In the maxilla, the following buttresses are distinguished: frontonasal, zygomaticoalveolar, palatine, and pterygopalatine; in the mandible, the alveolar and ascending buttresses.