Download Region 8: Nose, Nasal Cavity, and Paranasal Sinuses External

Region 8: Nose, Nasal Cavity, and Paranasal Sinuses
External Nose
--anterior nasal apertures (nostrils/nares)
*bounded laterally by the ala of the nose
--Cartilages of the External Nose
a. lateral nasal cartilage
b. great alar cartilages
c. septal cartilage (part of septum of nose)
--Inn of Exteral Nose
a. supratrochlear and infratrochlear nn from CN V1
b. infraorbital (nasal branch) n from CN V2
c. external nasal n: from ant. ethmoidal branch of nasociliary n
--Blood Supply of External Nose
a. angular artery: branch of facial a.
b. septal branch: from facial artery
**Veins: there is free anastomosis b/w blood vessels that can drain into
cavernous sinus
Nasal Cavity
--right and left sides are separated by nasal septum
--posterior nasal aperture (choana) in back
--separated from oral cavity by palate
--posteriorly: opens into nasopharynx
--portion in the confines of the alar carilages is called the vestibule (hairy)
--upper part of nasal cavity is lined with olfactory muvosa
--each nasal vavity ahs a floor, roof, medial, and lateral wall
*floor: palatine processes of the maxillar and horizontal plate of the palatine
bone (superior surface of hard palate)
*Medial wall: nasal septum, partition b/w right and left cavity (formed front
to back by septal cartilage, perpendicular plate of ehtmoid bone, and vomer)
a. nerves of the septum: nasopalatine n (from pterygopalatine
ganglion)
b. special sense of olfaction: olfactory nn through cribiform plate
c. BS of septum: anterior and posterior ethmoidal aa, septal branches
of sphenopalatine artery
*Lateral wall: uneven and complicated, formed by labyrinth and concha of
ethmoid bone, and inferior nasal concha
a. subdivided by delicate medial projections (sup, middle, inf conchae)
b. spaces underlying the concha (meatuses)
--spheno-ethmoidal recess
--superior meatus: underlies superior concha
--middle meatus: underlies middle concha  includes
ethmoidal bulla, hiatus semilunaris (curved slit below
ethmoid bulla that receives opening of maxillary sinus),
uncinate process (ridge located below semilunar hiatus),
ehtmoidal infundibulum (narrow passage that runs upward
and forward from semilunar hiatus, receives openings of
frontal sinus)
--inferior meatus: underlies inferior conchae  inferior concah
is a separate bone, nasolacrimal duct (from lacrimal sac
terminates in inferior meatus
c. nerves to lateral nasal wall
--special sense of olfaction: olfactory nerves through cribiform
plate
--general sensations of touch, pressure, pain, temp: V1 and V2
--secretory motor fibers: pterygopalatine ganglion containing
fibers from greater petrosal nerve (CN VII)
d. arteries of lateral nasal wall
--maxillary artery: sphenopalatine artery
Paranasal Sinuses
--cavities in the maxilla, frontal, sphenoid, and ethmoid bones
--Frontal Sinus
*drain into the middle meauts through the frontonasal duct
--Ethmoid sinuses (air cells)
*located in ethmoid labyrinth in honeycomb arrangement
--Maxillary Sinuses
*opens in the hiatus semilunaris or onto the uncinate process (middle
meatus)
--Sphenoid Sinuses
*opens into sphenoethmoidal recess
Pterygopalatine Fossa
--Communications of the Fossa
a. pterygomaxillary fissure
b. foramen rotundum
c. pterygoid canal
*nerve of the pterygoid canal (Vidian nerve): entryway for greater
petrosal branch of CN VII carrying preganglionic parasympathetic
nerve fibers, entry way for deep petrosal nerve carrying
postganglionic sympathetic fibers
d. inferior orbital fissure
*passageway for maxillary nerve, its zygomatic branch
e. sphenopalatine foramen
*passageway into nasal cavity for sphenopalatine artery
*passageway also for nasopalatine n
f. pterygopalatine canal: leading into the greater and lesser palatine foramina
--Contents of the Pterygopalatine Fossa
a. maxillary nerve
*zygomatic n branch: divides into zygomaticofacial and
zygomatiotemporal branches to supply skin on face and temporal
region
*posterior superior alveolar nn
*infraorbital n: freaches the face through the infraorbital foramen
b. pterygopalatine ganglion
*parasympathetic ganglion receiving preganglionic fibers from facial n
*located in pterygopalatine fossa below maxillary n and suspended by
pterygopalatine nn
*supplies secretory fibers to lacrimal gland and to mucosal glands in
the nasal, oral, and pharyngeal cavities
*Nerves from pterygopalatine ganglion:
--greater palatine branches
--lesser palatine branches
--nasopalatine nerve: passes through sphenopalatine foramen,
crosses roof of nasal cavity to reach nasal septum, supplies
nasal septum as it passes toward the incisive canal
c. Maxillary artery
*infraorbital artery
*sphenopalatine artery