1. Paranasal sinuses

2. Paranasal sinuses
Are air filled cavities found in the interior of frontal, maxillary, sphenoid and ethmoid bones
They communicate with nasal cavity through small openings or apertures
Maxillary and sphenoid rudimentary at birth, enlarge at 8years and fully formed in adolescent

5. functions of sinuses Immune system Resonating chamber for voice
Decrease weight of skull
Warm & moisten air
Shock absorbers
Immune system

6. Maxillary sinuses Are the largest sinuses
Paired, one on each side and equal size.
Pyramidal in shape with the body forming the lateral wall of the nose, and apex in zygomatic process of maxilla
Superolateral surface (Roof) is related to orbit
Anterolateral surface is related below to roots of upper molar and premolar teeth and to face in front
Posterior wall is related behind to infratemporal fossa

7. Sinus opens into middle meatus of the nose through hiatus semilunaris
Is innervated by infra-orbital and alveolar branches of maxillary nerve
Blood supply infra – orbital and superior alveolar branches of maxillary arteries

10. Frontal sinuses Two, contained within frontal bones
Are variable in size, most superior and second largest
Each is triangular in shape, extending upward above medial end of eyebrow and backward into medial part of the roof of orbit
Each drains onto lateral wall of middle meatus via frontonasal duct
Innervation by branches of supra – orbital nerve from ophthalmic nerve
Blood supply – branches of anterior ethmoidal arteries

11. Ethmoidal sinuses
Are formed by variable number of individual air chambers divided into anterior, middle and posterior groups bases on the location of their apertures on lateral wall of nasal cavity
Anterior group opens into ethmoidal infundibulum or frontonasal duct
Middle group onto ethmoidal bulla or lateral wall just above ethmoidal bulla
Posterior group onto lateral wall of superior nasal meatus

12. Ethmoidal sinuses are innervated by anterior and posterior branches of nasociliary nerve from ophthalmic nerve
Maxillary nerve from via orbital branches from pterygopalatine ganglion
Blood supply is from branches of anterior and posterior ethmoidal arteries

13. Sphenoidal sinuses They are two located within the sphenoid bone
Opens into the roof of nasal cavity through the apertures on the posterior wall of spheno – ethmoidal recess
Relations
above to cranial cavity (pituitary gland and to optic chiasma
Laterally tocranial cavity esp cavenous sinuses
Below and infront to nasal cavities

14. Innervation is provided by
Posterior ethmoidal branch of ophthalmic nerve
Maxillary nerve via orbital branches from pterygopalatine ganglion
Blood supply is via branches of pharyngeal arteries from the maxillary arteries