The existing literature documents an important role for the Eustachian tube (ET) in the pathogenesis and/or persistence of otitis media (OM). Cross-sectional studies report a lower prevalence of OM in older children, a better ET pressure-regulating function in older children and age-related differences in ET form, length and width, and the vector orientation of the paratubal musculature. These growth-related changes in ET structural relationships are demonstrably predictive of increasingly more efficient ET function (F) and, because the ET and paratubal musculature are intimately related to the cranial base, the vector orientation of the ET system can be reconstructed from osteological or radiographic data. Together, these observations suggest that measurable, age-related changes in ET-paratubal muscle vector relationships are reflected in more efficient ETF and, by consequence, a decreased OM risk. The overall goal of the proposed longitudinal study is to evaluate the validity of this hypothesis.