Which statement correctly describes the STJ axis orientation in the sagittal plane?

• A. 16 degrees medial in the sagittal plane.
• B. 16 degrees lateral in the sagittal plane.
• C. 30 degrees medial in the sagittal plane.
• D. 10 degrees medial in the sagittal plane.

Answer: (A)

The STJ axis is an oblique line that passes through the subtalar joint, not lying flat in the sagittal plane. When you view this axis in the sagittal plane, it tilts toward the midline by about 16 degrees. This medial tilt is the standard description you’ll see in anatomy references and boards, so describing it as 16 degrees medial in the sagittal plane is the most accurate representation of its orientation.

This medial tilt matters because the axis’ oblique orientation means subtalar motion couples components of movement from both the sagittal and frontal planes, influencing how inversion/eversion interacts with plantarflexion/dorsiflexion. The other options propose either a lateral tilt or a notably different degree of tilt, which don’t align with the typical anatomical description of the STJ axis in the sagittal view.