Sagittal plane position of the subtalar joint axis:
If the subtalar joint axis is more vertical than the average of 42 degrees in the sagittal plane, there will be more abduction and adduction of the foot as the joint is pronated and supinated (as motion occurs at 90 degrees to the axis).
If the subtalar joint axis is more horizontal in the sagittal plane, there will be more inversion and eversion of the foot as the joint is pronated and supinated
• a more vertical axis will appear to have a limited range of motion at the subtalar joint if inversion/eversion of the posterior aspect of the calcaneus is used to measure STJ range of motion
• more compensatory motion of the foot at the subtalar joint would occur in the transverse plane if the axis is more vertical may have implications for a foot staying on top of a foot orthoses and not sliding off.