Thigh flexion is primarily controlled by which nerve?

Thigh flexion is primarily controlled by the femoral nerve, which innervates several key muscles involved in this movement. The most notable muscle it affects is the iliopsoas, which is the primary flexor of the hip. Additionally, the femoral nerve innervates the quadriceps muscle, which assists in flexing the thigh and is critical for actions such as walking, running, and climbing.

The sciatic nerve, while significant for innervating muscles in the posterior compartment of the thigh (hamstrings), primarily facilitates extension at the hip rather than flexion. The obturator nerve mainly controls adduction of the thigh through innervation of the adductor muscles, and the inferior gluteal nerve primarily innervates the gluteus maximus, which is responsible for hip extension and external rotation rather than flexion. Hence, the femoral nerve's role as the primary nerve in controlling thigh flexion supports its identification as the correct answer in this case.