anatomy Anatomy () is the branch of morphology concerned with the study of the internal structure of organisms and their parts. Anatomy is a branch of natural science that deals with the structural organization of living things. It is an old scien ...

, the term nasal meatus can refer to any of the three

meatus In anatomy, a meatus (, , : meatus or meatuses)Entry "meatus" in Merriam-Webster Onlin ...

skull The skull, or cranium, is typically a bony enclosure around the brain of a vertebrate. In some fish, and amphibians, the skull is of cartilage. The skull is at the head end of the vertebrate. In the human, the skull comprises two prominent ...

nasal cavity 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 nas ...

: the superior meatus (''meatus nasi superior''), middle meatus (''meatus nasi medius''), and inferior meatus (''meatus nasi inferior''). The nasal meatuses are the spaces beneath each of the corresponding nasal conchae. In the case where a fourth,

supreme nasal concha The supreme nasal concha or highest nasal concha is a nasal concha (turbinate) that occurs in some cases. It is shaped like a seashell and found on the posterosuperior part of the lateral nasal wall.Supreme nasal concha. (n.d.) ''Medical Dictionary ...

is present, there is a fourth supreme nasal meatus.

Structure

The superior meatus is the smallest of the three. It is a narrow cavity located obliquely below the

superior concha The superior nasal concha is a small, curved plate of bone representing a medial bony process of the labyrinth of the ethmoid bone. The superior nasal concha forms the roof of the superior nasal meatus. Anatomy Anatomical relations The super ...

. This meatus is short, lies above and extends from the middle part of the

middle concha The medial surface of the labyrinth of ethmoid consists of a thin lamella, which descends from the under surface of the cribriform plate, and ends below in a free, convoluted margin, the middle nasal concha (middle nasal turbinate). It is rough, ...

below. From behind, the

sphenopalatine foramen The sphenopalatine foramen is a foramen of the skull that connects the nasal cavity and the pterygopalatine fossa. It gives passage to the sphenopalatine artery, nasopalatine nerve, and the superior nasal nerve (all passing from the pterygopala ...

opens into the cavity of the superior meatus and the meatus communicates with the posterior

ethmoidal cell 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 ...

s. Above and at the back of the

is the

sphenoethmoidal recess The sphenoethmoidal recess is a small triangular space superior to the superior nasal meatus of the nasal cavity into which the sphenoidal sinus opens. The sphenoethmoidal recess is situated supero posterior to the superior nasal concha The supe ...

which the

sphenoidal sinus The sphenoid sinus is a paired paranasal sinus in the Body of sphenoid bone, body of the sphenoid bone. It is one pair of the four paired paranasal sinuses.Illustrated Anatomy of the Head and Neck, Fehrenbach and Herring, Elsevier, 2012, page 64 T ...

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 The inferior nasal concha (inferior turbinated bone or inferior turbinal/turbinate) 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 bon ...

where the meatus extends along its length. On it is a curved fissure, the

hiatus semilunaris The semilunar hiatus (eg, hiatus semilunaris) 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 ...

, limited below by the edge of the

uncinate process of the ethmoid 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 sp ...

and above by an elevation named the

bulla ethmoidalis The ethmoid bulla (or ethmoidal bulla) is a rounded elevation upon the lateral wall of the middle nasal meatus (nasal cavity inferior to the middle nasal concha) produced by one or more of the underlying middle ethmoidal air cells (which open i ...

; the middle

ethmoidal cells 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 smal ...

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 An infundibulum (Latin for ''funnel''; plural, ''infundibula'') is a funnel-shaped cavity or organ. Anatomy * Brain: the pituitary stalk, also known as the ''infundibulum'' and ''infundibular stalk'', is the connection between the hypothalamus an ...

, 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 The pyramid-shaped maxillary sinus (or antrum of Nathaniel Highmore (surgeon), Highmore) is the largest of the paranasal sinuses, located in the maxilla. It drains into the middle meatus of the noseHuman Anatomy, Jacobs, Elsevier, 2008, page 209- ...

(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 The nasolacrimal duct (also called the tear duct) carries tears from the lacrimal sac of the eye into the nasal cavity. The duct begins in the eye socket between the maxillary and lacrimal bones, from where it passes downwards and backwards. The o ...

References

External links

* * — Coronal section {{Authority control

meatus In anatomy, a meatus (, , : meatus or meatuses)Entry "meatus" in Merriam-Webster Onlin ...

Otorhinolaryngology