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 - reterophyrangeal lymph nodes