The subtalar joint axis is oriented 16 degrees medial in which plane?

The subtalar joint axis is oriented 16 degrees medial in which plane?

• A. 16 degrees medial in the sagittal plane.
• B. 16 degrees lateral in the sagittal plane.
• C. 10 degrees medial in the sagittal plane.
• D. 20 degrees medial in the sagittal plane.

Answer: (A)

The subtalar joint axis is oblique, not aligned straight up the leg. In a side (sagittal) view, this axis tilts toward the midline by about 16 degrees. That medial tilt in the sagittal plane means hindfoot motion around the subtalar joint combines elements of plantarflexion with adduction when moving toward inversion, and dorsiflexion with abduction when moving toward eversion. The exact angle can vary between people, but describing it as a medial tilt of about 16 degrees in the sagittal plane captures how the axis directs rotation and couples movements across planes during gait.