PTTM Exam 1 Practice

Inversion and eversion mainly move at the subtalar joint, so the goniometer’s axis should align with the joint’s rotation. Placing the fulcrum on the anterior aspect of the ankle, midway between the medial and lateral malleoli, puts the axis through the center of the subtalar joint. This position lets the moving arm follow the true tilt of the foot during inversion and eversion and yields an accurate measurement. If the fulcrum sits over a malleolus or on the posterior aspect, the axis is off from the joint’s center, leading to a distorted reading due to misalignment with the actual rotation and soft tissue interference.