In the Inline and Perpendicular views:
Rotation made in one view, is reflected in the other
Objects are shown in 2D
The medial/lateral directions are identified in the Perpendicular view
In the 3D view:
The dot ① represents the intersection of the yellow line ② with the lead in the Inline view
The ruler ④ is only visible in the 3D view when you are in-plane with axial, coronal or sagittal orientations
For directional leads, the orientation is represented by a directional marker ③.