When assessing ankle plantarflexion/dorsiflexion, what is the alignment of the goniometer's moving arm?

• A. Along the medial malleolus
• B. Parallel to the lateral aspect of the fifth metatarsal
• C. Perpendicular to floor
• D. Along the anterior midline of the tibia

Answer: (B)

In ankle plantarflexion and dorsiflexion, the moving arm of the goniometer should follow the long axis of the foot. Position it parallel to the lateral aspect of the fifth metatarsal so it tracks the foot’s motion in the sagittal plane while the axis sits at the lateral malleolus. This alignment ensures the measured angle reflects true ankle movement rather than movements of the tibia or foot segments. Aligning the moving arm along the medial side, perpendicular to the floor, or along the tibia would not correspond to the foot’s direction of motion and would yield an inaccurate reading.