Nasal meatus

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Nasal meatus
Gray855.png
Meatuses shown on lateral wall
Identifiers
FMA 53146
Anatomical terminology

In anatomy, the term nasal meatus [1] can refer to any of the three meatuses (passages) through the skull 's nasal cavity: the superior meatus (meatus nasi superior), middle meatus (meatus nasi medius), and inferior meatus (meatus nasi inferior).

Contents

The nasal meatuses are the spaces beneath each of the corresponding nasal conchae. In the case where a fourth, supreme nasal concha is present, there is a fourth supreme nasal meatus.

Structure

Coronal section of nasal cavity Gray859.png
Coronal section of nasal cavity

The superior meatus is the smallest of the three. It is a narrow cavity located obliquely below the superior concha. This meatus is short, lies above and extends from the middle part of the middle concha below. From behind, the sphenopalatine foramen opens into the cavity of the superior meatus and the meatus communicates with the posterior ethmoidal cells. Above and at the back of the superior concha is the sphenoethmoidal recess which the sphenoidal sinus opens into. The superior meatus occupies the middle third of the nasal cavity’s lateral wall.

The middle meatus is the middle-sized and located nasal opening, lying underneath the middle concha and above the inferior concha where the meatus extends along its length. On it is a curved fissure, the hiatus semilunaris, limited below by the edge of the uncinate process of the ethmoid and above by an elevation named the bulla ethmoidalis; the middle ethmoidal cells are contained within this bulla and open on or near to it.

Through the hiatus semilunaris the meatus communicates with a curved passage termed the infundibulum, which communicates in front with the anterior ethmoidal cells and in rather more than fifty percent of skulls is continued upward as the frontonasal duct into the frontal air-sinus; when this continuity fails, the frontonasal duct opens directly into the anterior part of the meatus.

Below the bulla ethmoidalis and hidden by the uncinate process of the ethmoid is the opening of the maxillary sinus (ostium maxillare); an accessory opening is frequently present above the posterior part of the inferior nasal concha.

The inferior meatus is the largest of the three. It lies below the inferior concha and above the nasal cavity. It extends most of the length of the nasal cavity’s lateral wall. It is broader in the front than at the back, and presents anteriorly the lower orifice of the nasolacrimal canal.

Related Research Articles

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<span class="mw-page-title-main">Inferior nasal concha</span>

The inferior nasal concha is one of the three paired nasal conchae in the nose. It extends horizontally along the lateral wall of the nasal cavity and consists of a lamina of spongy bone, curled upon itself like a scroll,. The inferior nasal conchae are considered a pair of facial bones. As the air passes through the turbinates, the air is churned against these mucosa-lined bones in order to receive warmth, moisture and cleansing. Superior to inferior nasal concha are the middle nasal concha and superior nasal concha which both arise from the ethmoid bone, of the cranial portion of the skull. Hence, these two are considered as a part of the cranial bones.

<span class="mw-page-title-main">Nasal cavity</span> Large, air-filled space above and behind the nose in the middle of the face

The nasal cavity is a large, air-filled space above and behind the nose in the middle of the face. The nasal septum divides the cavity into two cavities, also known as fossae. Each cavity is the continuation of one of the two nostrils. The nasal cavity is the uppermost part of the respiratory system and provides the nasal passage for inhaled air from the nostrils to the nasopharynx and rest of the respiratory tract.

<span class="mw-page-title-main">Nasal concha</span> Piece of bone in the breathing passage of humans and other animals

In anatomy, a nasal concha, also called a nasal turbinate or turbinal, is a long, narrow, curled shelf of bone that protrudes into the breathing passage of the nose in humans and various animals. The conchae are shaped like an elongated seashell, which gave them their name. A concha is any of the scrolled spongy bones of the nasal passages in vertebrates.

<span class="mw-page-title-main">Orbital part of frontal bone</span>

The orbital or horizontal part of the frontal bone consists of two thin triangular plates, the orbital plates, which form the vaults of the orbits, and are separated from one another by a median gap, the ethmoidal notch.

<span class="mw-page-title-main">Uncinate process of ethmoid bone</span>

In the ethmoid bone, a sickle shaped projection, the uncinate process, projects posteroinferiorly from the ethmoid labyrinth. Between the posterior edge of this process and the anterior surface of the ethmoid bulla, there is a two-dimensional space, resembling a crescent shape. This space continues laterally as a three-dimensional slit-like space - the ethmoidal infundibulum. This is bounded by the uncinate process, medially, the orbital lamina of ethmoid bone, laterally, and the ethmoidal bulla, posterosuperiorly. This concept is easier to understand if one imagine the infundibulum as a prism so that its medial face is the hiatus semilunaris. The "lateral face" of this infundibulum contains the ostium of the maxillary sinus, which, therefore, opens into the infundibulum.

<span class="mw-page-title-main">Agger nasi</span>

The agger nasi is a small ridge on the lateral side of the nasal cavity. It is located midway at the anterior edge of the middle nasal concha, directly above the atrium of the middle meatus. It is formed by a mucous membrane that is covering the ethmoidal crest of the maxilla.

<span class="mw-page-title-main">Ethmoid sinus</span> Air-filled space near the nasal cavity

The ethmoid sinuses or ethmoid air cells of the ethmoid bone are one of the four paired paranasal sinuses. Unlike the other three pairs of paranasal sinuses which consist of one or two large cavities, the ethmoidal sinuses entail a number of small air-filled cavities. The cells are located within the lateral mass (labyrinth) of each ethmoid bone and are variable in both size and number. The cells are grouped into anterior, middle, and posterior groups; the groups differ in their drainage modalities, though all ultimately drain into either the superior or the middle nasal meatus of the lateral wall of the nasal cavity.

<span class="mw-page-title-main">Frontal sinus</span> Airspace below ridge of eyebrow in humam anatomy

The frontal sinuses are one of the four pairs of paranasal sinuses that are situated behind the brow ridges. Sinuses are mucosa-lined airspaces within the bones of the face and skull. Each opens into the anterior part of the corresponding middle nasal meatus of the nose through the frontonasal duct which traverses the anterior part of the labyrinth of the ethmoid. These structures then open into the semilunar hiatus in the middle meatus.

<span class="mw-page-title-main">Semilunar hiatus</span>

The semilunar hiatus is a crescent-shaped/semicircular/ curved slit/groove upon the lateral wall of the nasal cavity at the middle nasal meatus just inferior to the ethmoidal bulla. It is the location of the openings for the frontal sinus, maxillary sinus, and anterior ethmoidal sinus. It is bounded inferiorly and anteriorly by the sharp concave margin of the uncinate process of the ethmoid bone, superiorly by the ethmoidal bulla, and posteriorly by the ethmoidal process of the inferior nasal concha. It leads into the ethmoidal infundibulum; it marks the medial limit of the ethmoidal infundibulum.

<span class="mw-page-title-main">Ethmoidal labyrinth</span>

The ethmoidal labyrinth or lateral mass of the ethmoid bone consists of a number of thin-walled cellular cavities, the ethmoid air cells, arranged in three groups, anterior, middle, and posterior, and interposed between two vertical plates of bone; the lateral plate forms part of the orbit, the medial plate forms part of the nasal cavity. In the disarticulated bone many of these cells are opened into, but when the bones are articulated, they are closed in at every part, except where they open into the nasal cavity.

The ethmoid bulla is a rounded elevation upon the lateral wall of the middle nasal meatus produced by one or more of the underlying middle ethmoidal air cells. It varies significantly based on the size of the underlying air cells.

<span class="mw-page-title-main">Sphenoethmoidal recess</span>

The sphenoethmoidal recess is a small triangular space of the superior nasal meatus of the nasal cavity into which the sphenoidal sinus and the posterior ethmoidal air cells open. The sphenoethmoidal recess is situated superoposterior to the superior nasal concha, between the superior nasal concha and the anterior aspect of the body of the sphenoid bone.

<span class="mw-page-title-main">Maxillary hiatus</span>

The maxillary hiatus is the opening of a maxillary sinus into the middle nasal meatus of the nasal cavity. It is situated superoposteriorly upon the lateral nasal wall, opening into the nasal cavity at the posterior portion of the ethmoidal infundibulum. Its opening in the maxillary sinus is present upon the superior part of the medial wall of the sinus near the roof of the sinus; because of the position, gravity cannot drain the maxillary sinus contents when the head is erect.

The frontonasal duct is a duct through which either frontal sinus drains into the nasal cavity. Each frontal sinus opens into the frontonasal duct by an opening on the inferomedial part of the floor of the sinus. The frontonasal duct pases inferior-ward to open either into the middle nasal meatus at the anterior end of the ethmoidal infundibulum, or into the anterior ethmoidal air cells.

<span class="mw-page-title-main">Perpendicular plate of palatine bone</span>

The perpendicular plate of palatine bone is the vertical part of the palatine bone, and is thin, of an oblong form, and presents two surfaces and four borders.

<span class="mw-page-title-main">Frontal process of maxilla</span> Plate which forms part of the lateral boundary of the nose

The frontal process of the maxilla is a strong plate, which projects upward, medialward, and backward from the maxilla, forming part of the lateral boundary of the nose.

<span class="mw-page-title-main">Ethmoidal infundibulum</span>

The ethmoidal infundibulum is a funnel-shaped/slit-like/curved opening/passage/space/cleft upon the anterosuperior portion of the middle nasal meatus at the hiatus semilunaris. The anterior ethmoidal air cells, and (usually) the frontonasal duct open into the ethmoidal infundibulum. The ethmoidal infundibulum extends anterosuperiorly from its opening into the nasal cavity.

<span class="mw-page-title-main">Human nose</span> Feature of the human face

The human nose is the most protruding part of the human face. It bears the nostrils and is the first organ of the respiratory system. It is also the principal organ in the olfactory system. The shape of the nose is determined by the nasal bones and the nasal cartilages, including the nasal septum which separates the nostrils and divides the nasal cavity into two.

<span class="mw-page-title-main">Outline of human anatomy</span> Overview of and topical guide to human anatomy

The following outline is provided as an overview of and topical guide to human anatomy:

References

PD-icon.svgThis article incorporates text in the public domain from the 20th edition of Gray's Anatomy (1918)

  1. Maynard, Robert Lewis; Downes, Noel (2019). "Nasal Cavity". Anatomy and Histology of the Laboratory Rat in Toxicology and Biomedical Research. Elsevier. pp. 109–121. doi:10.1016/b978-0-12-811837-5.00010-1. ISBN   978-0-12-811837-5.