The femoral nerve innervates the quadriceps muscle. The femoral nerve innervates the muscles of the front of the thigh, including the crevices and quadriceps. The femoral nerve is the largest of the branches of the lumbar plexus. The femoral nerve travels downward from the outer edge of the psoas major muscle and enters the anterior thigh through the femoral canal in the inguinal region. Its muscular branch is distributed to the inner muscles of the anterior thigh, while its sensory branch is distributed to the skin of the anterior thigh and the inner calf. Once a patient has an injury to the femoral nerve, it often leads to paralysis of the quadriceps muscle. The patient is unable to extend the calf and is therefore unable to stand or walk on the ground. In addition, the patient will gradually develop muscle atrophy of the quadriceps. For this type of nerve injury, an electromyogram can be used as an adjunctive test.