Tibialis posterior acts on which structures during mid and late stance?

Tibialis posterior acts on which structures during mid and late stance?

• A. Pelvis and femur
• B. Knee and hip only
• C. Foot and tibia
• D. Shoulder and trunk

Answer: (C)

During mid- to late-stance, tibialis posterior acts on the foot and the tibia. Its tendon runs behind the medial malleolus and attaches to the navicular and midfoot bones, enabling inversion of the foot and helping to support the medial longitudinal arch as weight-bearing progresses. Because it also has proximal attachments on the tibia, its contraction helps stabilize the tibia relative to the foot and resist excessive pronation during stance. This is why the structures involved are the foot and tibia. It does not directly act on the pelvis, femur, knee, hip, shoulder, or trunk in this phase.

During mid- to late-stance, tibialis posterior acts on the foot and the tibia. Its tendon runs behind the medial malleolus and attaches to the navicular and midfoot bones, enabling inversion of the foot and helping to support the medial longitudinal arch as weight-bearing progresses. Because it also has proximal attachments on the tibia, its contraction helps stabilize the tibia relative to the foot and resist excessive pronation during stance. This is why the structures involved are the foot and tibia. It does not directly act on the pelvis, femur, knee, hip, shoulder, or trunk in this phase.