ABSTRACT
The maxillary and anterior ethmoidal sinuses arise as out-pouchings from the lateral nasal wall at an early stage of fetal development. At birth small maxillary, ethmoid and sphenoid sinuses are present. The sphenoid may be regarded as embryologically arising from a posterior ethmoidal cell whilst the frontal sinuses do not begin to develop until some months after birth and should be regarded developmentally as deriving from the anterior ethmoidal system.
