American Board of Surgery Qualifying Exam (ABS QE) Practice Test

Which nerve is potentially injured in a posterior hip dislocation?

1. Femoral nerve

2. Axillary nerve

3. Sciatic nerve

4. Median nerve

The correct answer is: Sciatic nerve

In the context of posterior hip dislocation, the sciatic nerve is the nerve most commonly at risk for injury. This is primarily due to the anatomical proximity of the sciatic nerve to the hip joint and the mechanism of the dislocation, where the femoral head moves posteriorly out of the acetabulum. When a posterior hip dislocation occurs, forces can directly stretch or compress the sciatic nerve, leading to potential injuries or deficits in function. Patients may present with symptoms such as weakness in knee flexion, loss of sensation below the knee, and difficulty with movements involving the hip or leg, depending on the extent of the nerve injury. The other nerves listed are not typically associated with posterior hip dislocations. The femoral nerve primarily innervates the anterior compartment of the thigh and is located more anteriorly. The axillary nerve innervates the shoulder region and is affected in shoulder dislocations rather than hip dislocations. The median nerve is primarily related to the forearm and hand and does not have a significant relationship with hip injuries.