Anatomy of the Nose and Paranasal Sinuses Flashcards
Turbinates (Conchae)
Inferior, middle, superior, supreme
Covered by erectile mucosa
Increases interior surface area
Warms, moisturizes and filters airflow
Superior Meatus
Area under superior turbinate
Drainage pathway of sphenoid and posterior ethmoid sinuses
Middle Meatus
Area underneath middle turbinate
Drainage pathway of the frontal, anterior ethmoid and maxillary sinuses
Inferior Meatus
Area underneath the inferior turbinate
Contains orifice of nasolacrimal duct
Uncinate Process
Sickle-shaped bone covered by mucoperiosteum
Part of the ethmoid bone
Anteriorly attaches to lacrimal bone
Inferiorly attaches to inferior turbinate
Superiorly attaches to lamina papyracea (80%), skull base or middle turbinate
Ethmoid Infundibulum
Pyramidal space
Houses the drainage pathways of maxillary, anterior ethmoid and frontal sinuses
Seems synonymous with OMC from this description
Recess Terminalis
When the uncinate inserts superiorly into the lamina papyracea, a blind pouch in the infundibulum is formed. This is the name of that pouch
Semilunar Hiatus
Gap emptying the ethmoid infundibulum
Between uncinate process and ethmoid bulla
Sphenopalatine Foramen
Posterior to the inferior attachment of the middle turbinate
Contains SPA, sensory nerve fibers, secretomotor fibers (parasympathetics from vidian nerve to pterygopalatine ganglion)
Concha Bullosa
Pneumatized turbinate (middle turb most common) May obstruct nasal cavity or OMC
Paradoxical Middle Turbinate
Middle turbinate that “turns” medially instead of laterally
Ostiomeatal Complex (OMC)
Region of the anterior ethmoids that contains the ostia of maxillary, frontal and ethmoid sinuses, lateral to the middle turbinate
Nasal Fontanelles
Areas of lateral nasal wall where no bone exists
Located above the insertion of the inferior turbinate
May be the site of the accessory maxillary ostia
Draw the anatomy of the lateral nasal wall including vascular supply
See Page 3 of Pasha to confirm
Nasolacrimal Duct and Sac
Duct lateral to anterior uncinate process
Sac lateral to agger nasi
Sac opens into inferior meatus via Hasner’s valve
Where is Hasner’s Valve
Inferior meatus
3 - 6mm anterior to level of maxillary sinus ostium
When does the Frontal Sinus develop?
Last sinus to develop
Does not pneumatize until 5 - 6 years old
Volume of an adult Frontal Sinus
4 - 7 mL by age 12 - 20 years old
5 - 10% will be aplastic/hypoplastic
Drainage of Frontal Sinus
Frontal Recess
Drains into anterior middle meatus
Most commonly medial to uncinate (when uncinate attaches superiorly to skull base or middle turb)
Vasculature in Frontal Sinus
Supraorbital Artery
Anterior Ethmoid Artery
Ophthalmic Vein (to Cavernous Sinus)
Supraorbital Vein (to anterior facial veins)
Innervation of Frontal Sinus
Supraorbital Nerve (V1)
Frontal Recess
Drainage between the frontal sinus and semilunar hiatus/middle meatus Boundaries: Posterior wall of agger nasi Lamina papyracea Middle Turbinate
Frontal Sinus Infundibulum
Space that drains into frontal recess
Superior to agger nasi
Foramina of Breschet
Small venules that drain sinus mucosa into dural veins
Frontal Cells
Anterior ethmoid cells that pneumatize frontal recess
May cause obstruction or pesistent disease
Posterior to agger nasi
4 Types
Type I Frontal Cell
Single cell above agger nasi
Below floor of frontal sinus (infundibulum)
Type II Frontal Cell
Multiple Cells above agger nasi
May extend into the frontal sinus proper
Type III Frontal Cell
Single large cell that extends supraorbitally through the floor of the frontal sinus
Attaches to the anterior table
Type IV Frontal Cell
Single isolated cell that is within the frontal sinus
When does the Maxillary Sinus Develop?
First do develop
Biphasic growth:
Age 3
Age 7 - 18
Volume of Adult Maxillary Sinuses
15mL
Largest paranasal sinus
Drainage of Maxillary Sinus
Ethmoid infundibulum (Middle meatus) 10 - 30% have accessory ostium
Vasculature of Maxillary Sinus
Branches of the maxillary artery
Corresponding veins to facial vein/pterygoid plexus
Innervation of Maxillary Sinus
Branches of Maxillary Nerve (V2)
Structures Adjacent to Maxillary Sinus
Lateral nasal wall
Alveolar process of maxilla (contains second bicuspid and first and second molars)
Orbital floor
Posterior maxillary wall (contains pterygopalatine fossa housing maxillary artery, pterygopalatine ganglion, branches of V2)
When do the Ethmoid Sinuses develop?
3 - 4 cells present at birth
Most developed paranasal sinus at birth)
Formed from 5 ethmoturbinals
Reach adult size by age 12 - 15 years old
Derivatives of First Ethmoturbinal
Agger Nasi
Uncinate
Derivative of Second Ethmoturbinal
Middle Turbinate
Derivative of Third Ethmoturbinal
Superior Turbinate
Derivative of Fourth - Fifth Ethmoturbinals
Supreme Turbinate
Volume of adult ethmoid sinuses
2 - 3 mL
Distributed among 10 - 15 aerated cells
Drainage of Ethmoid Sinuses
Anterior Cells: Into ethmoid infundibulum
Posterior Cells: Into superior meatus
Vasculature of the ethmoid sinuses
Anterior ethmoid artery Posterior ethmoid artery (from ophthalmic) Branches of SPA Maxillary veins Ethmoid veins (to cavernous sinus)
Distance relationship of anterior lacrimal crest, anterior/posterior ethmoid arteries and optic foramen
24/12/6 rule
Anterior Lacrimal Crest to AEA: 24mm
AEA to PEA: 12mm
PEA to Optic Foramen: 6mm
Innervation of ethmoid sinuses
Anterior ethmoidal nerve
Posterior ethmoidal nerve
From nasociliary nerve (V1)
Structures adjacent to the ethmoid sinuses
Skull base
Anterior ethmoidal artery (roof or anterior ethmoid cells)
Nasal Cavity
Orbit
Agger Nasi Cells
Most anterior or anterior ethmoid cells
Found anterior and superior to middle turbinate attachment to lateral nasal wall
Posterior wall of the agger nasi forms anterior wall of the frontal recess
Ethmoid Bulla
Largest of the anterior ethmoid cells
Lies above the infundibulum
Anterior ethmoid artery courses superior and posterior to this cell
Basal Lamella
Bony attachment of the middle turbinate to the lateral nasal wall
Separates anterior and posterior ethmoids
Anterior part inserts vertically into crista ethmoidalis
Middle part inserts obliquely into lamina papyracea
Posterior third attaches to the lamina horizontally
Onodi Cells
Ethmoid cells that pneumatize lateral or posterior to anterior wall of the sphenoid
Commonly mistaken as sphenoid cells
Optic nerve or carotid artery may indent into lateral wall
Haller Cells
Ethmoid cells that extend into the maxillary sinus above the ostium
Pneumatize medial and inferior orbital walls
Lamina Papyracea
Lateral thin bony wall of ethmoid sinus
Separates orbit from ethmoid cells
Part of the medial orbital wall
Fovea Ethmoidalis
Roof of ethmoid sinus
Supraorbital Cell
Pneumatization of posterior orbital plate of the frontal bone
Often forms septations in the frontal recess
Olfactory Fossa
Depression in anterior cranial cavity
Floor formed by cribriform plate
Olfactory cleft lies below
Keros Classification
Relationship between olfactory fossa and ethmoid roof (how deep is lateral lamella)
Type 1: 1 - 3mm
Type 2: 4 - 7mm
Type 3: 8 - 16mm
Lamellae of Ethmoid Bone
1 - Uncinate Process
2 - Bulla Ethmoidalis
3 - Basal Lamella of Middle Turbinate
4 - Lamella of Superior Turbinate
Embryology of Sphenoid Sinus
Evagination of nasal mucosa into sphenoid bone
Reaches adult size at 12 - 18 years old
Volume of an adult sphenoid sinus
0.5 - 8 mL
Drainage of Sphenoid Sinus
Sphenoethmoidal Recess (SER)
Vasculature of the Sphenoid Sinus
Posterior Ethmoidal Artery
Sphenopalatine Artery
Maxillary Vein (to Pterygoid Plexus)
Innervation of Sphenoid Sinus
Posterior Ethmoidal Nerves (V1)
Structures adjacent to the sphenoid sinus
Pons Sella Turcica (and therefore Pituitary) Carotid Artery (Lateral wall, 25% dehiscent) Optic Nerve (Lateral wall, 5% dehiscent) Cavernous Sinus (laterally) V1, V2 Clivus Septal branch of the SPA (inferior aspect of the sphenoid os)
Piriform Aperture
Bony anterior opening to nasal cavity
Bounded inferolaterally by maxilla
Bounded superiorly by nasal bones
Upper Lateral Cartilage
Paired cartilage supporting nasal sidewall
Inferior to nasal bone
Lower Lateral Cartilage
Paired cartilage forming the alae
Inferior to the lower lateral cartilage
Composed of lateral and medial crura
Lesser Alar Cartilage
Also called sesamoid cartilages?
Small cartilaginous plates lateral to the lower lateral cartilages
Muscles attached to the external nose
Procerus Nasalis Dilator naris anterior Depressor septi Levator labii superioris alaeque nasi All innervated by VII
Components of Nasal Septum
Quadrangular Cartilage
Perpendicular plate of the Ethmoid bone
Vomer
Nasal Crest (Maxillary and Palatine Bones)
Anterior Nasal Spine (Bony projection anterior to piriform aperture)
Blood Supply to Nasal Septum
Anterior Ethmoid Artery Posterior Ethmoid Artery Sphenopalatine Artery Greater Palatine Artery Superior Labial Artery
Nasal Vestibule
Just inside the naris
Anterior to the limen nasi (ridge that marks beginning of nasal cavity)
Lined by keratinized stratified squamous epithelium
Contains coarse hair-bearing skin inferiorly
Roof of Nasal Cavity
Bounded by nasal/frontal bone anteriorly
Bounded by cribriform plate and sphenoid face posteriorly
Floor of Nasal Cavity
Formed by palatine process of maxilla and horizontal plate of palatine bone
Communicates with piriform aperture anteriorly
Communicates with choana posteriorly
Sensory innervation to external nose
Nasal Dorsum: Supratrochlear, infratrochlear nerves (V1)
Nasal Tip: External branch of anterior ethmoid nerve (V1)
Malar, lateral nose, subnasal regions: Infraorbital nerve (V2)
Sensory innervation to Nasal Cavity
Anterosuperior Nasal Cavity: Internal nasal branch of anterior ethmoid nerve (V1)
Posterosuperior Nasal Cavity: Posterior ethmoid nerve (V1)
Posterior and Inferior Septum: Nasopalatine Nerve (V2)
Posterior lateral wall, floor and roof: Greater Palatine Nerve (V1)
Anterior septum, floor, lateral wall: Superior Alveolar Nerve (V2)
Branches of External Carotid Supplying the Nose
iMax > Descending Palatine Artery > Greater Palatine and lesser Palatine Arteries
iMax > Sphenopalatine Artery > Medial (Nasoseptal) and Lateral nasal arteries
Facial > Superior labial artery (columella, nasal septum, alar branches)
Facial > Lateral nasal artery
Facial > Angular artery (nasal sidewall, tip, dorsum)
Branches of Internal Carotid Supplying the Nose
Ophthalmic > Anterior ethmoid artery (lateral nasal wall and septum)
Ophthalmic > Posterior ethmoid artery (superior turbinate and septum)
Ophthalmic > Dorsal nasal artery (external nose)
Venous Drainage of Nose
Greater Palatine Vein > Posterior Facial Vein (EJ) and Cavernous Sinus
Septal Vein > Anterior Facial Vein (IJ)
Sphenopalatine Vein > Cavernous Sinus and Maxillary Vein (IJ)
Anterior and Posterior Ethmoidal Veins > Opthalmic Veins (Cavernous Sinus)
Angular Vein > Anterior Facial Vein (IJ) or Ophthalmic Veins (Cavernous Sinus)
Danger Triangle
Bounded by oral commissures and nasal bridge
Retrograde drainage from superficial veins may lead to intracranial extension of infection
Lymphatic Drainage of the Nose
External: Primarily to Level IB, root of nose drains to superficial parotid nodes
Internal: Anterior nasal cavity drains superficially, then to IB, remainder drains to retropharyngeal and upper cervical nodes
Nasal Cycle Overview
Airflow regulated by volume of venous sinusoids in nasal erectile tissue (inferior turb and anterior septum)
Hypothalamus also stimulates sympathetic tone via superior cervical sympathetic ganglia for vasoconstriction
Nasal Flow Formula
Pressure/Resistance
Flow may be laminar or turbulent
Sneeze Pathway
Allergens, ammonia, viral infections, exercise or other irritants stimulate trigeminal afferents
Complex efferent input triggers:
Slow inspiratory phase, glottic and velopharyngeal closure (increase subglottic pressure), sudden glottic opening (sneeze)
Asymmetric Congestive Response (Nasal Cycle)
Normal physiologic congestion/decongestion cycle
Alternates between nasal sides every 2 - 7 hours
Symmetric Congestive Response
Temporary bilateral congestion
Induced by exercise, changes in body position, hyperventilation, cold air, sulfur, histamine, other irritants
Lasts 15 - 30 minutes
Role of microvasculature in nasal congestion
Regulates volume, humidity and heat exchange
Resistance Vessels of the Nasal Mucosa
Arterioles and precapillary sphincters
Regulate blood flow to the nasal mucosa
Subepithelial Capillaries of the Nasal Mucosa
Fenestrated vessels
Allow for transport of solutes and fluids
Venous sinusoids of the nasal mucosa
Capacitance vessels
Determine blood volume and nasal congestion
Arteriovenous Anastomoses of the Nasal Mucosa
Regulate nasal blood flow
Allow blood to flow directly from resistance vessels to venous sinusoids
Sympathetic Regulation of Nasal Microvasculature
Provides vasoconstrictor tone to arteries and capacitance veins
Primarily via norepinephrine
Also via Neuropeptide Y (weak vasoconstrictor, enhances function of norepinephrine)
Lastly via Avian Pancreatic Polypeptide (APP)
Parasympathetic Regulation of Nasal Microvasculature
Controls secretions, dilates resistance vessels
Primarily via Acetylcholine
Also using Vasoactive Intestinal Peptide (VIP)
Also using Peptide Histamine Isoleucine (PHI)
Function of Nasal Mucociliary System
Humidification
Filtering
Eliminating debris and excess secretions from sinuses and nasal airway
Pattern of Nasal Mucociliary Flow
1cm/minute
Migration begins at floor of maxillary sinus > Natural Ostium > Nasal Cavity > Nasopharynx
Components of Nasal Mucociliary System
Ciliated, Pseudostratified Columnar Epithelium
Double-Layered Mucous Blanket
Mucus-Producing Glands
Location of Ciliated, Pseudostratified Columnar Epithelium within the nasal cavity
Anterior border begins at limen nasi
Double-Layered Mucous Blanket in the Nose
Deep: Less viscous, serous periciliary fluid (sol phase)
Superficial: More viscous, mucous fluid (gel phase)
Mucus-Producing Glands in the Nose
Goblet cells (Columnar, basal nucleus, secretory granules at lumen end) Deep and superficial seromucinous glands (serous or mucous acini with cuboidal-lined duct complexes) Intraeptihelial glands (20 - 50 mucous cells around a single duct)
Major Composition of Nasal Mucus
95% water 3% glycoproteins (mucin) 2% salts IgA Lysozymes (bacteriolytic) Lactoferrin (bacteriostatic)
