sinuses


 * Paranasal Sinuses**
 * Frontal - pair
 * Ethmoidal - pair
 * Spenoidal
 * Maxillary - pair
 * Frontal Sinus**
 * Lies between the outer and inner tables of the frontal bones.
 * It is variable in size.
 * It may be absent.
 * It may extend up to the sphenoid.
 * The fontal sinus empties into the middle meatus through the ethmoidal infundibulam or frontonasal duct.
 * Ethmoidal**
 * They lie between the orbit and the upper part of the nasal cavity.
 * It connects the multiple thin walled cavities.
 * It has multiple communications with the nasal foscia.
 * The sinus is separated from the orbit by the thin orbital plate of ethmoid.
 * Infection may spread to the orbit from sinuses through this, causing orbital cellulitis.
 * Sphenoidal Sinuses**
 * Contained within the body of the sphenoid bone.
 * They may communicate.
 * One may be longer than the other.
 * Relationship: Superiorly - Pituitary, optic chiasma
 * Maxillary Sinus**
 * Longest paranasal sinus.
 * Occupy the maxillary bone.
 * Pyramidal in shape.
 * Roof formed by floor of orbit
 * Floor formed by alveolar process (Roots of teeth may project into the sinus).
 * Medially - Nasal Fossa.
 * Laterally - Zygomatris process.
 * Drains into the middle meatus. ||
 * [[image:http://www.meddean.luc.edu/lumen/MedEd/Radio/curriculum/ENT/salena127c.jpg width="350" height="414"]] || [[image:http://www.meddean.luc.edu/lumen/MedEd/Radio/curriculum/ENT/salena125c.jpg width="350" height="470"]] ||  ||
 * [[image:http://www.meddean.luc.edu/lumen/MedEd/Radio/curriculum/ENT/jay3b.jpg width="350" height="350"]] || [[image:http://www.meddean.luc.edu/lumen/MedEd/Radio/curriculum/ENT/salena126b.jpg width="350" height="363"]] ||  ||
 * [[image:http://www.meddean.luc.edu/lumen/MedEd/Radio/curriculum/ENT/image589c.jpg width="540" height="540"]] ||  ||
 * **Applied Anatomy** ||  ||
 * **Applied Anatomy** ||  ||
 * **Applied Anatomy** ||  ||