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How do the paranasal sinuses reduce skull weight and affect the voice?

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Illustration showing different animals and their respiratory organs: a spider with book lungs, a chicken with lungs, a sponge with labeled inflow and outflow pores, a fish with gills, and a caterpillar with spiracles. — Respiratory system Different methods of respiration in animals.

It is a common suggestion that the paranasal sinuses serve to lighten the skull and act as resonance chambers for the voice; however, it is important to note that scientific evidence for these specific functional theories is currently lacking.1

While some anatomical texts describe the paranasal sinuses as air-filled cavities that help keep the weight of the skull within reasonable limits and serve as resonance chambers for human speech, these remain theoretical roles. In the study of phonation, the primary resonators are identified as the cavities formed by the pharynx, nasopharynx, nose, and oral cavity, which can be varied in size and shape to modulate the voice.23

The paranasal sinuses—comprising the maxillary, frontal, ethmoidal, and sphenoidal sinuses—are primarily characterized as outgrowths of the nasal cavity lined with mucous membrane.12