Sinusitis is a very common clinical complaint, which is attributed with inflammation of the membrane lining of any sinus, especially one of the Para nasal sinuses. The muco ciliary clearance function is affected as a result of anatomical or pathological abnormalities.

     Para nasal Sinuses are air filled spaces present within the bones around the nasal cavities. They are Frontal, Maxillary, Sphenoid and Ethmoid.

Frontal Sinus
     The paired frontal sinuses lie in the frontal bone deep in the supraciliary arch. It extends upwards above the medial end of eyebrow and backwards into medial part of the roof of the orbit. It opens in to the middle meatus of nose at the anterior end of the hiatus semilunaris either through the infundibulum or through the frontonasal duct. The right and left sinuses are usually unequal in size and rarely one or both may be absent.

Maxillary Sinus
     Maxillary sinus lies in the body of the maxilla and it is the largest of all the paranasal sinuses. It is pyramidal in shape, with its base directed medially towards the lateral wall of the nose and the apex directed laterally in the zygomatic process of the maxilla. It is the first Para nasal Sinus to develop.

Sphenoid Sinus
     The right and left sphenoid sinuses lie within the body of the sphenoid bone. They are unequal in size and separated by a septum. Each sinus opens into the sphenoethmoidal recess of the corresponding half of the nasal cavity.

Ethmoid Sinus
     These are numerous small inter communicating spaces which lie within the labyrinth of the ethmoid bone. The orbital plate of the frontal bone completes them from above, from behind by the sphenoidal conchae and the palatine bone and anteriorly by the lacrimal bone.