Not to be confused with the lateral femoral cutaneous nerve, the femoral nerve is a very important nerve that is responsible for flexion of the hip and extension of the knee. It also provides sensation to the skin over most of the front/inside part of the thigh and lower leg to about the ankle. Although injury to the femoral nerve is rare, procedures such as hip replacement surgery or cardiac catheterization can result in compression or even direct injury to the femoral nerve. This can cause severe pain down the inside of the thigh and lower leg and make walking extremely difficult.