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Anatomy lec #17
Apirl,17,2011
Paranasal Sinuses
-they are air-filled spaces within specific bones of the skull.
-named according to the bone located within.
-they drain their mucous secretion through tiny openings called osteium.
-outgrowth of the nasal cavity therefore they drain in it
(similar to the salivary gland they drain there secretion in the oral cavity:origin).
-lined with Respiratory Epithelium .
-N supply: Trigeminal n(v1 & v2).
Function
-lighten the skull weight.
-Resonance of sound.
-Alter the shape of the face.
-improve olfaction.
Maxillary Sinus
-located with maxillary bone.
- it is the largest sinus.
- pyramidal in shape.
-approximate volume 15ml.
-it open in the nasal cavity through tiny aperture (osteium)
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Into the middle meatus (floor of Hiatus Semilunaris).
-this sinus will not evacuate it content except when its filled.
-lined with Schneiderian Membrane (mix Respiratory epithelium with Endostium)
Which make it tougher than other sinuses.
Relation
Roof : floor of the orbit.
Floor : roots of maxillary molars (may extend to reach the canine ).
Medial : lateral wall of the nose.
Anterior : anterior wall of the maxilla.
Posterior : pterygopalatine fossa.
Arterial supply
Maxillary artery : -posterior superior alveolar
-infraorbital(middle superior alveolar & anterior superior alveolar branches)
Venous drainage
Pterygoid venous plexus.
Nerve supply
1) Posterior superior alveolar
Trigeminal N maxillary (pass through foramen rotundum)pterygopalatine fossa
(there it will give branches: posterior superior alveolar n)pass through its own
foramen on the posterior wall of the maxilla target the upper molar except the
mesobuccal root of 1st molar.
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On the posterior wall of the sinus.
2) Middle superior alveolar
From infraorbital nerve within the infraorbital groove.
On the lateral wall of the sinus.
3) Infraorbital
(middle superior alveolar & anterior superior alveolar branches)
On the roof of the sinus.
*Maxillary sinus like 2 papers in between spongy bone via it artery & nerve pass.
*Accumilation of fluid will compress nerve ending pain.
Development of the Maxillary sinus
-Rudimentary at birth .
-has 2 growth phases: slowduring first 3 yr
Rapid7-18 yr
Paralleling eruption of maxillary permanent dentition .
-rarely sinusitis in young age because they are still not developed.
Frontal sinus
-located within the frontal bone under the forehead which vary in different races.
- paired , separated by septum rarely equal in size.
-drain at infundibulum of middle meatus.
-nerve supply : supraorbital nerve
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Sphenoid sinus
-located within sphenoid bone.
-paired , separated by septum.
-drain into sphenoethmoidal recess.
- nerve supply : posterior ethmoidal nerve branch from ophthalmic.
-Relation :  Above :sella turcica(pituitary gland situated on it),optic chiasma.
lateral : cavernous sinus.
anterior: nasal cavity.
-sinusitis may cause : the optic chiasma blidness
infection to pituitary gland
meningitis
Development of the sinuses
Exactly As the silde no addition….
Forgive me for any mistake!
Done by : Asmaa al-Khoujah