The incidence of iatrogenic peripheral nerve injury during hip arthroplasty procedures has been reported to be between 0.6 and 1.3 percent. The relative risk of nerve palsy is higher in certain groups of patients such as women, patients with developmental dysplasia of the hip, and those who have undergone revision arthroplasty. In this study, the dynamic relationship between the acetabulum and the sciatic nerve, which is important for preventing sciatic nerve palsy during the hip surgery, was investigated. The sciatic nerve was exposed in 69 cadaveric hips. The relationship between the bony acetabulum and the sciatic nerve was examined in three different positions; as the ipsilateral hip was flexed; extended; or in neutral position. We found that the middle part of the posterior acetabular rim was closer to the sciatic nerve than its superior or inferior parts. The sciatic nerve was perilous when the ipsilateral hip was flexed and the middle part of the posterior acetabular rim was more risky than the superior or inferior parts, in terms of iatrogenic sciatic nerve injury.