Figure 2. Normal appearance of the left hip with no fluid in the anterior synovial space. In this image, obtained by scanning slightly more proximally than in Figure 1, the growth plate is well visualized.

Figure 1. Sonographic appearance of the right hip demonstrating a fluid collection (arrow) in the anterior synovial space. This space is measured from the anterior surface of the femoral neck to the posterior surface of the joint capsule underlying the iliopsoas muscle (red line).