THE NOSE & PARANASAL SINUSES Surgical Anatomy
Ramon Antonio B. Lopa, MD Clinical Associate Professor Department of Otorhinolaryngology UP-PGH
External Triangles of the Nose
External Nose: Bones and Cartilages
Valves of the Nose
Walls of the Nasal Cavity !
Medial: nasal septum (not always in the midline)
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Lateral wall: turbinates
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Roof: cribriform plate
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Floor: palate
Anterior: nares
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Posterior: choanae
Nasal Septum
Nasal Septum, Cadaver
Pseudostratified Columnar Ciliated
Nasal septum with mucosa -Respiratory epithelium -Covered with mucosal blanket -Ciliary beat of epithlium is backwards to pharynx -Vascular
Nasal septal arteries Kiesselbach’s plexus or Little’s area: common cause of bleeding in children
Nasal septum: cadaver
Sphenopalatine artery
Nasopalatine nerve
Kiesselbach’s Plexus
Nasal septal nerves
Marked Septal Deviation
Lateral Nasal Wall
Posterior Choanae
3Turbinates & 3 Meati
CT Scan of Turbinates & Meati
LNW, with Mucosa, Cadaver
Erectile Tissues
Supreme Turbinate
LNW with Turbinates Cut Hiatus semilunaris Ethmoidal bulla Uncinate process Nasolacrimal duct
Airflow Patterns
Laminar Air Flow by the Turbinates
Nasal Heating & Humidification
Acts Like a Car Radiator
Under the Inferior Turbinate: Nasolacrimal Duct
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LNW: turbinates cut, cadaver Hiatus Semilunaris Bulla Uncinate Process
Nasolacrimal Duct
Uncinate Process !
Sharp ridge of bone, sagittally-oriented
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Boomerang-shaped
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Superior border is concave, parallel to ethmoidal bulla
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Has varied insertions to LNW which affects formation of frontal recess
Uncinate Process, Endoscopic View
Hiatus Semilunaris A 2-D cleft between the uncinate process & ethmoidal bulla
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Sagittally oriented
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Superior HSL leads to lateral sinus when present
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Inferior HSL serves as “door” to the ethmoidal infundibulum
Hiatus semilunaris
Ethmoidal bulla
Uncinate process
Ethmoidal Bulla !
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The largest & most consistent air cell in the anterior ethmoid group Posterior to uncinate process Part of the ostiomeatal complex of nose
gl mt b hsl
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up
Ethmoidal bulla, endoscopic
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Ethmoidal Infundibulum !
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A 3D space extending from HSL anteroinferiorly & anterosuperiorly to the LNW, with the maxillary ostium in its floor Lateral to the uncinate process
Ethmoidal Infundibulum !
Boundaries: – Medially: uncinate process – Laterally: lamina papyracea – Posteriorly: anterior surface of bulla
Four Bony Walls of the LNW
Blood Supply of the LNW
Nasal Cavity, Coronal View
Ostiomeatal Complex
Significance of OMU !
Blockage of the OMU by secretions, tumors, foreign bodies or anatomical defects lead to development of sinusitis
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Treatment: removal of offending blockers or surgical correction of defect to facilitate easy drainage of the sinuses
Ostiomeatal Complex
Ostiomeatal Complex, Axial View 1 Hiatus semilunaris (inferior) 2 Infundibulum 3 Superior Hiatus semilunaris 4 Lateral Sinus Dnl – nasolacrimal duct Cm – middle turbinate Lp – lamina papyracea Glm – ground lamella S
-- septum
Lateral Sinus !
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Suprabullar recess and retrobullar recess, not constant Boundaries: – – – – –
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Inferiorly: roof of the bulla Superiorly: roof of ethmoid Laterally: lamina papyracea Medially: middle turbinate Retrobullar recess: ground lamella posteriorly and ethmoid bulla anteriorly
Accessed through the superior HSL
Before & After ESS of the OMC
Ground Lamella, Rt Middle Turbinate, Lateral View STABILITY
SAGITTAL
CORONAL
AXIAL
Posterior
Anterior
Paranasal Sinuses FRONTAL ETHMOID -Anterior -Middle -Posterior MAXILLARY SPHENOID
The Paranasal Sinuses
The Paranasal Sinuses !
Maxillary : the largest
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Ethmoid : most complex & frequently infected, divided into anterior, middle & posterior groups
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Frontal : between the frontal bones
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Sphenoid : on top of the nasopharynx, under the sella
Functions of the Paranasal Sinuses !
Resonance of voice
Air reservoir
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Lighten the skull
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Serve as “crumple zone” for the face in trauma
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Protects the brain from direct injury
Openings of the Sinuses !
Maxillary : middle meatus via infundibulum
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Ethmoids: anterior & middle--middle meatus; posterior--superior meatus
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Frontal : middle meatus via infundibulum
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Sphenoid : spheno-ethmoidal recess in the superior meatus
Development of the Sinuses
Maxillary Sinus, Coronal CT
Fluid in the Maxillary Sinus
Maxillary Sinus Drainage
Mucociliary Clearance of Sinuses
Surgery for Maxillary Sinusitis
Caldwell Luc Surgery for Maxillary Sinus
ETHMOID SINUS GROUP
Fovea Ethmoidalis Crista Galli Cribriform Plate Septum
Lateral Lamina
Ethmoidal cells
Lamina Papyracea Turbinates
ETHMOIDS
ETHMOIDS
Ethmoidal Labyrinth !
Boundaries: – Lateral wall: lamina papyracea – Medial wall: superior & middle turbinates – Superiorly: walled off by fovea ethmoidalis of frontal bone
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Open in the other directions
Ethmoidal Air Cells
Ethmoid Air Cells, Axial View
Agger Nasi Cell
Agger Nasi Cell
Haller Cell !
Infraorbital ethmoidal cell
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Found inferior and lateral to ethmoidal bulla
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Intimately related to infundibulum
Onodi Cell !
Sphenoethmoidal cell
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Posterior ethmoid cell lateral & superior to sphenoid sinus
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Intimately related to optic nerve
Ethmoidal Parts !
Ethmoidal roof – Lateral part is thick, formed by fovea ethmoidalis of frontal bone, 0.5 mm – Medial part is thin, formed by lateral lamella of cribriform plate, 0.2 mm
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Olfactory fossa – Lateral is the lateral lamella – Floor is the cribriform plate
Type 1 Cribriform Plate
Type 2 Cribriform Plate
Type 3 Cribriform Plate
Assymetric Cribriform Plate
Course of the Anterior Ethmoid Artery, Right 1 Orbital 2 Labyrinthine 3 Cranial 4 Nasal
3 2 4
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Anterior Ethmoidal Artery
AEA at the Dome of the Ethmoid
Frontal Sinus
Frontal Sinus Drainage
Hourglass-shaped Frontal Sinus & Frontal Recess Frontal sinus ostium
Drainage The frontal sinus drains via a small outflow tract into the ethmoid sinus/nasal cavity. The outflow tract is hour-glass shaped with the true ostium (3-4 mm) at the narrowest portion.
Frontal Recess !
Lower part of hourglass; upper part is floor of frontal sinus; narrowest part is frontal sinus ostium
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“Frontonasal duct” a misnomer
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May be narrow if bulla is large or agger nasi is anterior
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Opens into middle meatus or infundibulum depending attachment of uncinate process
Frontal Recess, CT Scans
Uncinate Process Variation
Sphenoid Sinus
Sphenoid Sinus & Relations
Sphenoid Sinus & Cavernous Sinus
Sphenoid Sinus Ostium
