Ball and socket joint Ball and socket joint The ball and socket joint (or spheroid joint) is a type of synovial joint in which the ball-shaped surface of one rounded bone fits into the cup-like depression of another bone. The distal bone is capable of motion around an indefinite number of axes, which have one common center. It enables the bone to move in many places (nearly all directions). An enarthrosis is a special kind of spheroidal joint in which the socket covers the sphere beyond its equator. Examples of this form of articulation are found in the hip, where the round head of
X-ray of hip dysplasia be drawn in the pediatric pelvis assessing hip dysplasia are as follows: In the adult hip there are important landmarks to be recognized on plain film radiographs (Figure 5): In the adult hip, normal joint space ranges from 3 to 5 mm and must be uniform. Values under 2 mm are consistent with joint space narrowing. The most important measurements are detailed in Figure 6 and Table 1. Figure 6: Acetabular depth value under 250 characterizes the dysplastic hip. In normal conditions the acetabulum covers 75% of the femoral head. This coverage can be determined by three different measurements: lateral