**2.3 Mucociliary clearance**

*Rhinosinusitis*

may not be the case [2]. In the lateral nasal wall there lie openings of maxillary, frontal, ethmoid, and sphenoid sinuses. The lateral nasal wall is convoluted and has got three turbinates: superior, middle, and inferior turbinate. Sometimes there can also be a supreme turbinate. Beneath each turbinate lies the corresponding meatus, namely superior meatus, middle meatus, and inferior meatus, respectively. Superior meatus is confined to the posterior third of lateral wall, the middle meatus about two thirds of the length, and inferior meatus extends along the whole length of the lateral wall. Superior meatus has opening of posterior ethmoids, while the sphenoid opens in the sphenoethmoidal recess. Middle meatus harbours the opening of frontal, maxillary, and anterior ethmoidal sinuses. The

The superior and middle turbinate are the part of ethmoid bone, while inferior turbinate is a separate bone. Middle turbinate is the most important landmark for the sinus surgery, and therefore, its attachments are important. The anterior portion lies in the sagittal plane and inserts into the lateral border of cribriform plate of ethmoidal bone. The central portion rotates in the coronal plane and is attached to the lamina papyracea. This part is known as basal or ground lamella of middle turbinate. The ground lamella separates anterior ethmoidal cells from the posterior ethmoidal cells. The posterior portion of the middle turbinate runs in the horizontal plane and is attached to the perpendicu-

The sinuses are arranged in pairs in relation to each nasal cavity, comprising two groups: anterior and posterior. The maxillary, frontal, and anterior ethmoids form the anterior group and these drain into the middle meatus. The posterior ethmoids and sphenoid form the posterior group which drain into superior meatus and sphenoethmoidal recess, respectively. The maxillary sinus exists at birth as small but definitive cavity adjacent to the middle meatus and it gradually enlarges with the eruption of primary dentition, and by the age of 7th year, it reaches the level of nasal floor. It attains the maximum dimension by the age of 21 years, when its floor lies 4–5 mm below the floor of nose [3]. The natural ostium is located in the superior aspect of the medial wall of the sinus and drains into hiatus semilunaris. Frontal sinus is rudimentary at birth and it reaches the level of orbital roof at the age of 9 years and its development is completed by 20 years. There is minimal development of sphenoid sinus until 3 years of age after this sphenoid sinus begins to pneumatise the sphenoid bone. There is a great variation in the extent of pneumatisation of the sphenoid sinus. It may be present as a small pit in a predominantly nonpneumatised sphenoid bone—Conchal Type. It may extend up to the anterior wall of sella turcica—Presellar type. It may pneumatise the entire sphenoid body below and behind the sella turcica so that the pituitary forms distinct bulge in its posterosuperior wall—Sellar Type [4]. Ethmoidal sinuses are the most complex of the sinuses and they are present at

The term OMC is used to refer collectively the maxillary sinus ostium, ethmoid infundibulum, hiatus semilunaris, middle meatus, frontal recess, ethmoidal bulla, and uncinate process. It describes the final drainage pathway of the anterior group

nasolacrimal duct opens in the inferior meatus.

birth and attain adult size by the age of 12 years.

**2.2 Osteomeatal complex**

lar plate of palatine bone.

**2.1 Paranasal sinuses**

**58**

of sinuses.

Secretions of nose and sinuses form a sheet called mucous blanket. Mucous blanket consists of a superficial mucus layer, floating on the top of cilia which constantly beat like a conveyer belt towards the nasopharynx; the inspired bacterial viruses and dust particles are entrapped on the mucous blanket and carried to the nasopharynx to be swallowed. Hampering of the mucociliary mechanism leads to the stasis of secretions and subsequent sinusitis [5].
