PARANASAL AIR SINUS

INTRODUCTION

paranasal air sinus are air spaces in the bone surrounding the nasal cavity

we have 4 air sinus that open into the nasal cavity through lateral wall

• ethmoidal air sinus

• frontal air sinus

• sphenoidal air sinus

• maxillary air sinus

AIR SINUS

air cavities present in the skull

they are rudimentary at birth developed at age 6-7

they make the skull lighter and humidify the air

sinus infection is common in cold, they are called sinusitis

FRONTAL SINUS

lies deep in the superciliary arch

• anterior- eyebrow

• posterior - the medial roof of the orbit

opens in the middle meatus through the infundibulum or frontonasal duct

right and left sinus are unequal in size

better developed in males than females

• vessels

  • artery - supraorbital artery

  • vein - ophthalmic vein

  • lymph drain - submandibular nodes

  • nerve supply - supraorbital nerve

MAXILLARY AIR SINUS

lies in the body of the maxilla

largest paranasal sinus

pyramidal

opens in middle meatus in the lower part of hiatus semilunaris

• site of the opening is reduced due to overlapping of meatus by

  • ethmoid

  • lacrimal bone

  • palatine

  • thickness of mucosa

first paranasal sinus to develop

• Anatomy

  • roof

    • floor of orbit

  • floor

    • alvelar process of maxilla

    • has conical elevations by upper molar

  • canine may project to the anterolateral wall

• vessels

  • artery

    • facial

    • infraorbital

    • greater palatine

  • veins

    • facial vein

    • pterygoid venous plexus

  • lymph drain

    • submandibular node

  • nerve supply

    • superior alveolar nerve

SPHENOIDAL AIR SINUS

lies within the body of the sphenoid

they are separated by a septum

opens into sphenoethmoidal recess

• Relations

  • superior - optic chiasma

  • lateral - internal carotid artery

  • posterior - cavernous sinus

• vessels

  • artery supply

    • posterior ethmoidal

    • internal carotid artery

  • venous drainage

    • pterygoid venous plexus

    • cavernous sinus

  • lymph drainage

    • retropharyngeal nodes

  • nerve supply

    • the posterior ethmoidal nerve.

    • orbital branches of pterygopalatine gangion

ETHMOIDAL SINUS

numerous small interconnected space

• Anterior ethmoidal sinus

  • 1- 11 air sinus

  • opens in the anterior part of hiatus semilunaris

  • nerve supply - anterior ethmoidal nerve

  • lymph drain - submandibular

• Middle ethmoidal air sinus

  • 1-7 air sacs

  • opens in the middle meatus

  • nerve supply

    • anterior ethmoidal nerve

    • orbital branch of the pterygopalatine ganglion

  • lymph drain - submandibular lymph node

• Posterior ethmoidal air sinus

  • 1-7 air sacs

  • opens in superior meatus of the nose

  • nerve supply

    • posterior ethmoidal nerve

    • orbital branch of the pterygopalatine ganglion

    • lymph drain - retropharyngeal lymph nodes