Casting with maximal pronation locks which joint?

Casting with maximal pronation locks which joint?

• A. Subtalar joint
• B. Midtarsal joint
• C. Chopart joint
• D. Tibiotalar joint

Answer: (B)

Maximal pronation during casting locks the midtarsal joint, the transverse tarsal joints that connect the hindfoot to the midfoot (talonavicular and calcaneocuboid). When the foot is set into a pronounced pronated position, these joints align in a way that they move as a single rigid unit, effectively immobilizing the midfoot. This creates a stable, stiff cast across the midfoot, while the ankle and subtalar joints retain some motion. The midtarsal joint is the key structure that becomes locked in this position.

Maximal pronation during casting locks the midtarsal joint, the transverse tarsal joints that connect the hindfoot to the midfoot (talonavicular and calcaneocuboid). When the foot is set into a pronounced pronated position, these joints align in a way that they move as a single rigid unit, effectively immobilizing the midfoot. This creates a stable, stiff cast across the midfoot, while the ankle and subtalar joints retain some motion. The midtarsal joint is the key structure that becomes locked in this position.