Which of the following describes the flexor synergy pattern for the lower extremity?

• A. Hip: flexion, adduction, internal rotation; Knee: extension; Ankle: plantarflexion; Toes: flexion
• B. Hip: flexion, abduction, external rotation; Knee: flexion; Ankle: dorsiflexion and inversion; Toes: extension
• C. Hip: flexion, abduction, internal rotation; Knee: flexion; Ankle: dorsiflexion; Toes: extension
• D. Hip: extension, adduction, internal rotation; Knee: flexion; Ankle: dorsiflexion; Toes: extension

Answer: (B)

This question tests the lower-extremity flexor synergy pattern seen with certain upper motor neuron injuries. In this pattern, the leg moves as a coordinated group: the hip goes into flexion with abduction and external rotation; the knee flexes; the ankle dorsiflexes (foot moves upward) and often the foot shows inversion; and the toes extend. The option that describes hip flexion with abduction and external rotation, knee flexion, ankle dorsiflexion with inversion, and toes extension matches this classic flexor synergy exactly, making it the best choice.

The other options mix components that belong to the opposite extensor pattern or alter key directions (for example, hip extension with adduction and internal rotation; knee extension; ankle plantarflexion; toes flexion), which do not fit the flexor synergy.