The objective of the proposed study is o determine the normal biomechanical function of the interosseous membrane (IOM) in the lower extremity of man and to use this knowledge to better understand its role in the stabilization of tibial fractures. The methods to be used are three fold: 1. Development of constituants: Observe the development of ultra and micro structure of (IOM) at various stages of development in the human fetus. By relating the structural development to the onset of motion in the extremities a "form-function" effect may begin to be established. 2. Modeling: Mechanical testing of specimens of IOM will establish the visco-elastic properties needed to quantitatively model the IOM in simplified form. This model will become part of a whole leg model which will incorporate the active as well as passive properties of the system and relate the behavior of the system to the function of the IOM. The model will duplicate normal function as well as function for a fractured limb. 3. Verification: The model will be tested in its passive behavior by comparing to an existing, passive, laboratory model of a leg with a fracture. Once it is refined to pass the passive test, it will be compared to live subjects with all active properties involved. If the model can be refined sufficiently to appear relevant to in vivo behavior, it can then be used to predict the behavior of various treatment techniques for mechanical deficits of the leg or of other portions of the limbs which do not have a 2-bone-IOM structure.