[Retracted] Establishment of Difficult Caudal Epidural Blockade Prediction Model

Figure 2

Colour flow Doppler imaging of a “successful puncture” (a). Ultrasound images of the transverse (b) and longitudinal (c) plane of the sacral hiatus. Real-time turbulence or color flow and expansion of the caudal space during an injection can be seen. The area of turbulence or color flow is the caudal space. The “white triangle” represents the sacral cornua, the “downward arrow” represents the sacrococcygeal ligament, the “leftward arrow” represents the base of the sacrum posterior surface, and the “double-ended arrow” represents the caudal space.

(a)

(b)

(c)