Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content +++ Nasal Cavity ++ Nasal embryology The embryologic precursors of the nasal turbinates arise in the eighth week of gestation as ridges along the lateral nasal wall. Maxilloturbinal: originates inferiorly from the maxillary process and gives rise to inferior turbinate. Ethmoturbinals: arise superiorly from ethmoid bone, five arise with only four persisting throughout development. First ethmoturbinal: Ascending portion gives rise to agger nasi Descending portion gives rise to uncinate process (UP) Regresses during development Second ethmoturbinal: gives rise to middle turbinate Third ethmoturbinal: gives rise to superior turbinate Fourth and fifth ethmoturbinals: gives rise to supreme turbinate (when present) Primary furrows: form the recesses separating the ethmoturbinals and gives rise to meati First primary furrow: separates first and second ethmoturbinals; gives rise to middle meatus Second primary furrow: gives rise to superior meatus Third primary furrow: gives rise to supreme meatus External nasal anatomy Subcutaneous layers of the nose Mnemonic = “Subcutaneous Fat DeeP S = Superficial fatty layer (connected to dermis) F = Fibromuscular layer (nasal superficial musculoaponeurotic system [SMAS]) D = Deep fatty layers (contains neurovascular system) P = Periosteum/perichondrium Optimal plane of dissection is located between D and P as it is avascular and heals with minimal fibrosis External nasal landmarks Nasion: corresponds to nasofrontal suture Radix: nasal root; centered at nasion, extends inferiorly to the level of the lateral canthus and superiorly by equivalent distance Rhinion: corresponds to bony-cartilaginous junction along nasal dorsum Supratip break: a break in the nasal profile separating the nasal dorsum and lobule located immediately superior to the tip defining point Supratip lobule: portion of lobule located superior to tip-defining point Tip defining point: two points located at the highest, medial, and cephalic portion of the lateral crus; corresponds to light reflex externally Infratip lobule: portion of lobule located inferior to tip-defining point and superior to infratip break Infratip break: lobule-columella junction Nasal sill: nostril rim located between columella and alar facial attachment Nasal tip support Major tip supports Medial and lateral crura Attachment of medial crura to caudal edge of quadrangular cartilage Attachment of upper lateral cartilage to lower lateral cartilage (“scroll area”) Minor tip supports Skin-soft tissue envelope (attachment of lower lateral cartilage to overlying skin and musculature) Sesamoid complex (located between lateral crura and pyriform aperture) Interdomal ligament (located between lower lateral cartilages) Anterior nasal spine Cartilaginous septal dorsum Membranous nasal septum Nasal osteology Two nasal bones fuse in the midline to form a pyramidal shape Nasal bones are thicker superiorly than inferiorly Nasal bone attachments = Superior: nasal process of frontal bone Lateral: frontal process of maxilla Pyriform aperture = bony opening into the nasal cavity bounded by Superior: caudal margin of nasal bones Inferior: alveolar process of maxilla Lateral: frontal process of maxilla Medial: nasal septum Nasal cartilages Upper lateral cartilage (ULC) Attached superiorly to nasal bones Articulates inferiorly with ... Your Access profile is currently affiliated with '[InstitutionA]' and is in the process of switching affiliations to '[InstitutionB]'. Please click ‘Continue’ to continue the affiliation switch, otherwise click ‘Cancel’ to cancel signing in. Get Free Access Through Your Institution Learn how to see if your library subscribes to McGraw Hill Medical products. Subscribe: Institutional or Individual Sign In Username Error: Please enter User Name Password Error: Please enter Password Forgot Password? Forgot Username? Sign in via OpenAthens Sign in via Shibboleth You already have access! Please proceed to your institution's subscription. Create a free a profile for additional features.