From the Guidelines
The four sinuses develop at different ages throughout childhood and adolescence, with the maxillary and ethmoid sinuses present at birth, the sphenoid sinuses developing around age 3-5 years, and the frontal sinuses beginning to develop around age 6-8 years. The development of the sinuses is a gradual process that occurs over several years. The maxillary sinus is the first to begin significant pneumatization between birth and 12 months, and its floor reaches the level of the floor of the nose by approximately 12 years of age 1. The ethmoid sinuses are present at birth and reach adult size at 12 to 14 years of age 1. The sphenoid sinuses begin to develop around age 3-5 years and reach full development by adolescence, typically around age 12-15. The frontal sinuses are the last to develop, beginning around age 6-8 years and continuing to develop through adolescence, often not reaching full size until late adolescence or early adulthood (around age 18-20). Key points to consider include:
- The maxillary sinus develops first, with significant pneumatization occurring between birth and 12 months
- The ethmoid sinuses are present at birth and reach adult size by 12-14 years of age
- The sphenoid sinuses develop around age 3-5 years and reach full development by adolescence
- The frontal sinuses begin to develop around age 6-8 years and continue to develop through adolescence. This sequential development explains why certain sinus infections or conditions are more common in specific age groups, such as ethmoid sinusitis in young children and frontal sinusitis in adolescents 1.
From the Research
Development of the Four Sinuses
The development of the four sinuses (maxillary, frontal, ethmoid, and sphenoid) occurs at different stages of growth.
- The maxillary sinus is present at birth and increases in size until the end of the 18th year 2.
- The ethmoidal labyrinth is also of appreciable size in newborns, while the sphenoidal and frontal sinuses are still only predispositioned 3.
- The frontal and sphenoidal sinuses develop later, with the frontal sinus already developed in 4-year-olds and the sphenoidal sinus developed by this age as well 3.
- By the age of 12, the paranasal sinuses reach their final form and a size equivalent to the adult 3.
Age-Related Changes
Age-related changes in the dimensions and volume of the normal maxillary sinus have been investigated, with the most extensive period of growth occurring during the first 8 years 2.
- The growth pattern of the maxillary sinus includes changes in vertical, horizontal, and antero-posterior directions 2.
- No bilateral dimorphism was observed, but gender-related differences were found in children over the age of 8 years 2.
- The maximal values of all diameters and volume of the maxillary sinus are reached by the end of the 16th year 2.
Clinical Importance
Understanding the development of the paranasal sinuses is important for accurate interpretation of diagnostic imaging and for planning surgical interventions 4, 5.
- Knowledge of the unique anatomy and pneumatization of children's sinuses is essential for understanding the pathogenesis of sinusitis and its complications 4.
- A practical guide for assessing normal paranasal sinuses in children based on the relationship of the sinuses to anatomical landmarks at various stages of development can help pediatric radiologists provide accurate interpretation of diagnostic imaging 5.