Review Question - QID 216603

This patient who presents with an ipsilateral deviation of the trunk and contralateral rotation of the pelvis has a Trendelenburg gait. This is caused by weakness of the hip abductors secondary to superior gluteal nerve damage.

The superior gluteal nerve is formed from the L4-S1 nerve roots and exits the pelvis through the greater sciatic notch superior to the piriformis muscle. It innervates the hip abductor muscles including the gluteus medius, gluteus minimus, and tensor fascia lata. It can be damaged through trauma to the posterior hip as in a fracture or dislocation event. Patients with deficient abductor muscle function will present with a Trendelenburg gait where they shift the trunk over the injured extremity. This adjustment shifts the center of weight over the extremity such that abduction is not needed to maintain pelvic stability. When asked to stand on the injured leg, the contralateral pelvis will rotate inferiorly because of deficient abduction function as well.

Incorrect Answers:
Answer 1: The femoral nerve innervates the anterior compartment of the thigh, which is responsible for knee extension as well as some hip flexion. Patients with femoral nerve deficits will have instability during the stance phase.

Answer 2: The inferior gluteal nerve innervates the gluteus maximus, which is responsible for hip extension. Patients with inferior gluteal nerve deficits will present with difficulty climbing stairs, stepping onto a bus, and rising from a chair.

Answer 3: The obturator nerve innervates the medial compartment of the thigh, which is responsible for hip adduction. Patients with obturator nerve deficits will present with difficulty in moving the legs past the midline such as in crossing the legs.

Answer 4: The sciatic nerve innervates the posterior compartment of the thigh as well as all compartments of the leg. Patients with sciatic nerve deficits will present with foot drop and a stiff knee gait.

Bullet Summary:
Superior gluteal nerve deficits will present with ipsilateral deviation of the trunk and contralateral rotation of the pelvis during gait (Trendelenburg).