Upper one third is olfactory areas (mucosa)
Lower two thirds is respiratory areas (mucosa)
Boundaries (walls) of nasal cavity
Nasal conchae
Three horizontal projections from lateral wall
Superior, middle and inferior nasal conchae
Divide nasal cavity into four areas
Superior meatus
Middle meatus
Inferior meatus
Sphenoethmoid recess
Superior meatus
Between superior and middle conchae
Has openings from posterior ethmoidal sinuses
Middle meatus
Wider and longer than superior
Depressed area-atrium-at anterior end
Ethmoid infundibulum at anterior end
Leads to frontonasal duct
Duct leads to frontal sinus
Ethmoidal bulla (swelling)
Rounded projection at inferior root of middle meatus
Represents bulge of ethmoid air cells (sinuses)
Groove called semilunar hiatus immediately beneath leads to infundibulum
Contains openings for frontal, maxillary, and anterior ethmoidal sinuses
Frontal sinus opening at anterior end of semilunar hiatus/infundibulum
Maxillary sinus opening at posterior end of semilunar hiatus
Variable openings for ethmoid air cells
Inferior meatus
Below inferior concha
Receives nasolacrimal duct opens into anterior end
Sphenoethmoidal recess:
Posterior and superior to superior concha
Receives opening of sphenoidal sinus
Innervation
Posterior region of nasal cavity
Nasal septum: maxillary nerve (CN V 2 ) → nasopalatine nerve to nasal septum
Lateral wall: lateral branches of lateral palatine nerve
Anterior and superior regions of nasal cavity: anterior and posterior ethmoidal nerves, branches of nasociliary nerve from ophthalmic
nerve (CN V 1 )
Olfactory epithelium innervated by olfactory nerve (CN I)
Arterial supply
Sphenopalatine artery (branch of maxillary artery)
Anterior and posterior ethmoidal arteries
Greater palatine artery
Superior labial and lateral nasal branches of facial artery
Venous drainage
Plexus of veins beneath nasal mucosa drains to
Sphenopalatine veins
Facial veins
Ophthalmic veins
Lymphatic drainage
Posterior nasal cavity to retropharyngeal nodes
Anterior nasal cavity to submandibular nodesParanasal sinuses
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Sinus Description
Frontal Paired sinuses, lying anteriorly in frontal bone and draining into semilunar hiatus of middle meatus
Ethmoid Paired anterior, middle, and posterior sinuses in ethmoid bone; anterior and middle draining into middle meatus
(hiatus semilunaris and ethmoid bulla, respectively), and posterior, into superior nasal meatus
SphenoidalPaired sinuses, in sphenoid bone, draining into sphenoethmoidal recess
Maxillary Paired sinuses, in maxilla, draining into middle meatus (semilunar hiatus); largest sinus (20-30 ml)
There are four pairs of paranasal sinuses, which are open chambers within several of the bones surrounding the nose and orbits. They are lined
with respiratory epithelium, assist in warming and humidifying the inspired air, and drain their mucus secretions into the nasal cavities. Blowing the
nose clears the nasal cavity and sinuses of excess secretions.
Extensions of nasal cavity into maxillary, ethmoid, frontal, and sphenoid bones
Lined with respiratory epithelium
Present at birth and increase in size until adulthood
Air filled
Frontal sinuses (2)
Between inner and outer tables of frontal bone
Can be detected around age 7
Maxillary sinuses (2)