Superior gluteal nerve -the superior gluteal nerve supplies gluteus minimus and medius-two muscles that are important abductors of the hip-as well as tensor fasciae latae. these muscles stabilize the pelvis when walking. the gluteus medius and minimus work in such a way that when you are standing on your right leg only, the muscles on the right side are supporting the left side of the pelvis. when you are standing on your left leg only, the muscles of the left side are supporting the right side of the pelvis. if a patient exhibits a characteristic hip drop on the uninjured side (in this case, the left side) while standing on the injured side (right), this is called trendelenburgs sign. it occurs when the superior gluteal nerve-the nerve supply to the abductors of the thigh-is disrupted due to injury or disease.
nerve to piriformis and nerve to obturator internus allow those muscles to laterally rotate the thigh. however, if one of these muscles was denervated, the other might be able to compensate and prevent a significant loss of function. the sciatic nerve has no direct muscular branches; however, its two branches, common fibular and tibial nerves, innervate the posterior compartment of the thigh and all the muscles of the leg. a disruption to the sciatic nerve would lead to a significant motor deficit. the femoral nerve innervates the quadriceps. if this nerve were damaged, a patient would present with an inability to extend the knee.
