What are the main functions of the paranasal sinuses?

The paranasal sinuses lighten the skull, resonate the voice, humidify and warm inspired air, and contribute to facial growth during development.

How are the paranasal sinuses classified based on drainage?

The paranasal sinuses are classified into an anterior group (frontal, anterior and middle ethmoidal, and maxillary sinuses draining into the middle meatus) and a posterior group (posterior ethmoidal and sphenoidal sinuses not draining into the middle meatus).

Which is the largest paranasal sinus and what are its key features?

The maxillary sinus is the largest, pyramidal in shape, located in the maxilla. It opens high on the medial wall into the middle meatus, and its floor is related to the roots of molars and premolars, often causing drainage issues and dental-related infections.

What are the clinical implications of maxillary sinusitis?

Maxillary sinusitis is the most common sinus infection, often causing pain in the upper teeth or infraorbital area. Drainage is challenging due to the high ostium, potentially requiring procedures like antral puncture or Caldwell-Luc operation for relief.

How do the ethmoidal sinuses differ from other sinuses?

The ethmoidal sinuses are multiple small air cells in the ethmoidal labyrinth, divided into anterior, middle, and posterior groups that drain into different nasal meatuses. Their thin walls can allow infections to spread into the orbit.

What are the key anatomical relations of the sphenoidal sinus?

The sphenoidal sinus is in the sphenoid bone, with important relations above to the pituitary gland and optic chiasma, laterally to the cavernous sinus and internal carotid artery, and below to the nasopharynx, making it susceptible to spreading infections.

Why is frontal sinusitis clinically significant?

Frontal sinusitis causes frontal headaches and pain, and its proximity to the frontal lobe and orbit means infections can spread to the anterior cranial fossa or orbit, potentially causing abscesses or cellulitis.

Paranasal Sinuses – Drainage & Clinical

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