Which sinuses are present at birth?

At birth, the maxillary and ethmoid sinuses are indeed present and fully developed. The maxillary sinuses are the largest of the paranasal sinuses and are located within the maxillary bones. They play a crucial role in vocal resonance and the development of the facial skeleton. The ethmoid sinuses, which are situated between the eyes, consist of a collection of small air cells that contribute to the function of the nasal cavity. Both of these sinuses are critical at birth and serve important functions early in life.

The frontal and sphenoid sinuses, on the other hand, do not develop until later in childhood. The frontal sinuses typically begin to develop around two years of age and do not reach full size until late adolescence. The sphenoid sinuses also begin to develop in early childhood but are not present at birth. This timing of development is crucial for understanding the anatomy of the sinuses and their role in different age groups. Therefore, recognizing that only the maxillary and ethmoid sinuses are present at birth aligns with the established developmental timeline for these anatomical structures.