US-guided intra-articular hip injection on a long-axis scan. (a) Probe and patient position to perform long-axis US-guided intra-articular hip injection. (b) Anatomical scheme and (c) US scan of long-axis intra-articular hip injection. IP iliopsoas muscle, A acetabulum, F femur, asterisk labrum, arrow needle tip, arrowheads joint capsule. (d) US scan showing hyaluronic acid (circles) intra-articular injection