1. The paranasal sinuses are air-filled cavities within the bones of the face and skull. They include the maxillary, frontal, ethmoid, and sphenoid sinuses. 2. The sinuses are lined with mucous membrane and ciliated cells that help clear debris and bacteria through the mucociliary system towards the nasal cavity. 3. In addition to humidifying inhaled air, the sinuses may help with facial growth, resonance of the voice, and absorbing shock from facial impacts.

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Paranasal Sinuses:
Anatomy and Function
Glen T. Porter, MD
Francis B. Quinn, MD
UTMB Department of Otolaryngology
Galveston, TX
January 2002

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Case Report—1000B.C.

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7 bones
4 paired sinuses
4 turbinates
3 meati
Drainage system
Nervous supply
Vascular supply
Related structures
Sinus Anatomy Overview

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Maxilloturbinal
Ethmoturbinal
Middle turbinate
Superior turbinate
Supreme turbinate
Agger nasi
Uncinate process
Ethmoid infundibulum
Sinuses
Maxillary
Ethmoid
Embryology

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Sinus
Development

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Pediatric Sinuses

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Ethmoid
Maxilla
Palatine
Lacrimal
Pterygoid plate of
Sphenoid
Nasal
Inferior Turbinate
Bony Structure

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Arterial Supply
External Carotid
Maxillary A.
Sphenopalatine
Internal Carotid
Ophthalmic A.
Ant. Ethmoid
Post. Ethmoid
Supraorbital
Supratrochlear

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Innervation

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Neurovascular Supply

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Sinus Drainage Schema

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Ethmoid Sinus
Development
! Present at birth
! Anterior/Posterior
! Variability
Structure
! Volume/shape
! Roof
! Lateral wall

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Ethmoid Roof
•Anterior 2/3
•Posterior 1/3
Keros I
Keros II
Keros III

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Ethmoid
Cells
Supraorbital, Frontal Bulla, Concha Bullosa, Haller’s, Onodi Cells

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Ethmoid Sinus—Related
Structures
Basal Lamella of the Middle Turbinate
! Three planes
Agger nasi cell
! Childhood sinus
Ethmoid Bulla
! Hiatus Semiluninaris/Superior Hiatus Semilunaris
! Suprabullar/retrobullar recesses (Sinus Lateralis)
Ethmoid Infundibulum/Uncinate Process
Anterior/Posterior Ethmoid Arteries
Osteomeatal complex

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Basal/Ground
Lamella
Basal/Ground Lamella
Of the Middle Turbinate

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The Agger Nasi Cell

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Ethmoid Bulla
Uncinate Process
Hiatus Semilunaris

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Ethmoid Infundibulum

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Suprabullar/Retrobullar Recess

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Ethmoid Arteries

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Osteomeatal Complex
Middle meatus
Maxillary Sinus Ostium
Anterior Ethmoid
Drainage

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Maxillary Sinus
Development
! Present at birth
! Biphasic growth
! Level of the floor
Structure
! Volume & shape
! Walls, floor, roof

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Maxillary Sinus

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Maxillary
Sinus

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Maxillary Sinus
Related Structures
! Fontanelles
! Natural ostium
! Haller’s Cells &Sinusitis
! Osteomeatal complex
! Accessory Ostium
! Nasolacrimal duct

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Fontanelles

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Natural Ostium
-Haller’s cells
Accessory Ostium

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Nasolacrimal Duct

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Frontal Sinus
Development
! Frontal bone at birth
! Age 5
Structure
! Volume and shape
! Ostium
! Walls
! Anterior vs. posterior
Related Structures
! Frontal recess

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Frontal Sinus
Ostium
Frontal recess
Boundaries
Dumbbell shape
Sinus Lateralis
Frontal Bulla

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Sphenoidal Sinus
Development
Arise within the nasal capsule (no pouch)
Age 3 begins to pneumatize
Structure
! Volume/variable pneumatization
! Wall thickness
! Position within the sphenoid
! Relation to sella turcica
! Sellar and postsellar relationships

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Sphenoid Sinus Pneumatization

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Sphenoid Sinus
Sphenoid Sinus

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Sphenoid Sinus

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Sphenoid Sinus
Ostium
! Size (.5-4mm)
! Location (sinus floor, anterior nasal floor, anterior
sinus wall, superior turbinate, cribiform plate)
! Bony dehiscence
Related Structures
! Sphenoethmoidal recess
! Sphenoid rostrum
! Onodi cell

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Sphenoid Ostium
Sphenoethmoid Recess
Sphenoid Rostrum

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The Onodi Cell

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Microscopic Anatomy
Mucosa
! Cilliated columnar epithelial cells
! Anatomy
! Beat frequency
! Inhibitory effects of contact
! Noncilliated columnar cells
! Distribution
! Function
! Basal cells

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Microscopic Anatomy—Cont’d
Goblet Cells
! Glycoproteins—viscosity and elasticity
! Innervation (para=thick, symp=thin)
Basement membrane
! Submucosal glands
! Distribution

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Microscopic Anatomy

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Mucous Blanket
Two layers
! Superficial layer
! Sol layer
Function
! Superficial layer traps bacteria and
particulate matter.
! Enzymes, antibodies, immune cells

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Mucociliary Transport
Directional Flow of Mucous
! Toward the choanae
Ostium drainage—a stubborn beast
! Hilding, MD
Contact inhibition
! Haller’s cells
! Surgery

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Mucociliary Transport

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Function of Paranasal Sinuses
Humidifying and warming inspired air
Regulation of intranasal pressure
Increasing surface area for olfaction
Lightening the skull
Resonance
Absorbing shock
Contribute to facial growth

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New Frontiers
Sleep apnea and the sinuses
! Humidification contributes up to 6.9mm Hg serum
pO2
! Mouth breathers noted to have decreased end-tital
CO2—increased serum CO2—apneas (high
baseline)
Nitric Oxide (NO)
! NO produced primarily in sinuses
! Toxic to bacteria, fungi, viruses
! Increases cilliary motility

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Case Report
39 yom with h/o sinus disease c/o
headache, rhinorrhea.
PMHx of “sinus surgery” years ago
ROS reveals h/o two episodes of
meningitis in past few years
PE: right superior nasal mass. S/p
FESS. Clear rhinorrhea.

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References
Anon, Jack B., et al, Anatomy of the Paranasal Sinuses, Theime, New York,
c1996.
Bhatt, Nikhil J., Endoscopic Sinus Surgery: New Horizons, Singular
Publishing Group, Inc., San Diego, c1997.
Bailey, Byron J., et al, Head & Neck Surgery -- Otolaryngology, Lippincott
Williams & Wilkins, Philadelphia, c2001.
Lundberg, J., Weitzberg, E. Nasal Nitric Oxide in Man. Thorax 1999;
54(10):947-952.
McCaffrey, Thomas V., Rhinologic Diagnosis and Treatment, Thieme, New
York, c1997.
Marks, Steven C. Nasal and Sinus Surgery, W.B. Saunders Co., Philadelphia,
c2000.
Navarro, Joao A.C., The Nasal Cavity and Paranasal Sinuses, Springer,
Berlin, c2001.
Watelet, J.B., Cauwenberge P. Van, Applied Anatomy and Physiology of the
Nose and Paranasal Sinuses. Allergy 1999; 54, Supp 57:14-25.