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
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