12: Paranasal Sinuses

CHAPTER 12

PARANASAL SINUSES

Overview and Topographic Anatomy

Frontal Sinus

Ethmoid Sinus

Maxillary Sinus

Sphenoid Sinus

Clinical Correlates

Imaging

Questions

Overview and Topographic Anatomy

GENERAL INFORMATION

Paranasal sinuses: invaginations from the nasal cavity that drain into spaces associated with the lateral nasal wall

Each is lined by a respiratory epithelium

Morphology of the sinuses is highly variable

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DRAINAGE OF THE PARANASAL SINUSES AND ASSOCIATED STRUCTURES

All paranasal sinuses drain into the nasal cavity

Different sinuses serve as drainage conduits for different regions

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Frontal Sinus

GENERAL INFORMATION

The two frontal sinuses typically are asymmetrical

Rudimentary at birth and usually well-developed by the age of 7 or 8 years

Display a prime expansion when the 1st deciduous molars erupt and another when the permanent molars begin to appear at about age 6

Drainage varies; often drain in front of, above, or into the ethmoidal infundibulum

Primary lymphatic drainage is to the submandibular lymph nodes

The frontal sinus receives its nerve supply from branches of the ophthalmic division of the trigeminal nerve

Relations of Sinus

Superior: anterior cranial fossa and contents

Inferior: orbit, anterior ethmoidal sinuses, nasal cavity

Anterior: forehead, superciliary arches

Posterior: anterior cranial fossa and contents

Medial: other frontal sinus

Location of Ostium

Middle meatus

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ARTERIAL SUPPLY

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NERVE SUPPLY

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Ethmoid Sinus

GENERAL INFORMATION

May find 3 to 18 ethmoid air cells on each side

Ethmoid air cells may invade any of the other 3 sinuses

The middle ethmoid air cells produce the swelling on the lateral wall of the middle meatus called the ethmoid bulla

Primary lymphatic drainage is to the submandibular lymph nodes for the anterior and middle ethmoid sinuses; and the retropharyngeal lymph nodes for the posterior ethmoid sinus

Relations of Sinus

Superior: anterior cranial fossa and contents, frontal bone with sinus

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Jan 5, 2015 | Posted by in General Dentistry | Comments Off on 12: Paranasal Sinuses
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