Arrow
To draw an arrow on the image:
Click Diagnose in the menu bar.
Click Arrow 
.
Notes
The arrow annotation can be created in all viewers except the 3D viewer.
The arrow annotation line thickness can be chosen.
Click to indicate the tail.
Click to indicate the head.
The arrow is shown in the viewer and added to the Annotation tab 
on the smart panel under the group of Annotations. Click 
to change the color or delete the arrow. To move the arrow, click and drag the annotation on the viewer.