The Embryological Development of the Middle Ear Space — A New Concept

The classical embryology of the middle ear and associated spaces was described by Hammar in 1902.1 He held that these cavities were lined by an unbroken entodermal membrane derived from the first branchial (pharyngeal) pouch. <) However, this formation did not occur simply, but was accomplished by the ballooning-out of four distinct sub-pouches, each of which gave rise to a specific adult structure. This embryologic concept was reexamined, validated and given clinical significance by Proctor? who studied the adult remnants of these structures.