The Trendelenburg Test assesses hip stability. The examiner sits behind the patient and places thumbs on the PSIS and hands on the iliac crests to check for level height. The patient then stands on one leg, with the unsupported leg flexed at the knee and hip. In normal function, the unsupported pelvis elevates slightly, indicating that the gluteus medius muscle properly abducts the supported hip. If the pelvis drops on the unsupported side or remains level, it is considered a positive Trendelenberg Sign, indicating a weak gluteus medius or intra-articular pathology in the supported pelvis.