beam but measuring only 10 mm in length, was glued with cyanoacrylate to the surface of the bone. The bone sacrificial piece and the beam were then covered with Teflon tape (Figure 2-9).

       All tests took place in a temperature controlled aqueous solution, in a cylindrical plexiglas container. Temperature plays an important role in fatigue testing of bone [7]. Fatigue life has been found to depend significantly upon temperature of bone [15]. These data suggest that a linear relationship exists between the number of cycles to failure and range of temperature. For example, the fatigue life at room temperature (22' Q is one half that at physiologic (37' Q for bone.

       Additionally, it seems reasonable that if any advantageous structural adaptation exists near the foramen regarding toughness, then such adaptation may give the best results at physiological temperature. All beams were tested at a physiological temperature of 37'C in a calcium buffer solution to prevent leakage of calcium ions [26]; otherwise, leakage of ions can cause a reduction in modulus of nearly 2.5% [26]. A heater (Fisher Scientific Automerse Immersion Heater Model 199) was used to control the solution temperature at 37C. The testing solution consisted of 0.9% saline solution with a concentration of 57.5 mg/L of CaC12 [26]. The specimens were allow to thaw for

2 hours and acclimate at least 45 minutes in the bath prior to testing.

                             Mechanical Testing Plan

       From the five pairs of metacarpi (12 bones) procured, a total of fourteen beams were mechanically tested. Four were dorsal specimens used for protocol development only. The remainders were palmer beams.