The subtalar joint frontal plane angle is measured between which structures?

The subtalar joint frontal plane angle is measured between which structures?

• A. Tibia and first metatarsal
• B. Femur and tibia
• C. Posterior calcaneus and posterior lower leg
• D. Pelvis and femur

Answer: (C)

In this measurement, you’re focusing on the hindfoot’s orientation relative to the leg in the coronal (frontal) plane. The subtalar joint’s frontal plane angle is defined by the line along the posterior aspect of the calcaneus (the heel bone) and a line along the posterior aspect of the lower leg. The angle between those two lines shows hindfoot varus or valgus relative to the leg, which is exactly what the subtalar frontal plane angle captures. Choosing lines between the tibia and the first metatarsal would reflect forefoot-to-leg alignment, not hindfoot alignment. Lines between the femur and tibia pertain to the knee, and pelvis-to-femur relates to hip-pelvis orientation, not the subtalar joint.

In this measurement, you’re focusing on the hindfoot’s orientation relative to the leg in the coronal (frontal) plane. The subtalar joint’s frontal plane angle is defined by the line along the posterior aspect of the calcaneus (the heel bone) and a line along the posterior aspect of the lower leg. The angle between those two lines shows hindfoot varus or valgus relative to the leg, which is exactly what the subtalar frontal plane angle captures.

Choosing lines between the tibia and the first metatarsal would reflect forefoot-to-leg alignment, not hindfoot alignment. Lines between the femur and tibia pertain to the knee, and pelvis-to-femur relates to hip-pelvis orientation, not the subtalar joint.