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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