Load-generated intracortical fluid flow is proposed to be an important mediator for regulating bone mass and morphology . Although the mechanism of cellular response to induced flow parameters, i.e., fluid pressure, pressure gradient, velocity, and fluid shear stress, are not yet clear, interstitial fluid flow driven by loading may be necessary to explain the adaptive response of bone, which is either coupled with load-induced strain magnitude or independent with matrix strain per se . It has been demonstrated that load-induced intracortical fluid flow is contributed by both bone matrix deformation and induced intramedullary (IM) pressure . To examine the hypothesis of fluid flow generated adaptation, it is necessary to test the mechanism under the circumstances of solely fluid induced bone adaptation in the absence of matrix deformation. While our previous data has demonstrated that bone fluid flow and its associated streaming potential product can be influenced by the dynamic IM pressure quantitatively , the objective of this study was to evaluate fluid induced bone adaptation in an avian ulna model using oscillatory IM fluid pressure loading in the absence of bone matrix strain. The potential fluid pathway was measured in the model.