The SACH foot provides motion in which planes?

• A. Sagittal plane plantarflexion and limited frontal plane mediolateral motion
• B. Frontal plane motion only
• C. Dorsiflexion only
• D. Inversion/eversion only

Answer: (A)

This question tests how a SACH foot moves. The SACH foot is a non-articulating prosthetic foot, so there isn’t a true ankle joint to permit full movement. Its design allows motion mainly in the sagittal plane: the cushioned heel compresses and the forefoot comes down, enabling plantarflexion to absorb shock and help the foot roll forward during stance. There is only a small amount of side-to-side motion in the frontal plane, thanks to the flexible keel and cushion, but this is limited. It does not provide true dorsiflexion, nor does it offer dedicated inversion/eversion.