Visualizing and understanding a 3D ultrasound display requires development of some strength in spatial 
orientation. Because the B and C 2D display planes are relative to the A (Acquired) scan-plane, a blanket assumption cannot be made that one view (A, B or C) always represents the coronal, sagittal or transverse view.
Both the B and C 2D display planes are orthogonal (rotated 90 degrees) to the A (Acquired) plane, so it can be confusing to distinguish which image plane is “flipped” 90 degrees, versus which image is “rotated” 90 degrees.
In this Quick Concepts video, the four quadrant (multi-planar) display is explained, as well as the purpose and positioning of the orientation dot (or axis-point).
Related Quick Concepts: 2D/3D/4D Basics and 3D/4D Acquisition Tips.
