Image Viewer > Advanced Viewing

The Show Angles Tool displays the angle between the selected ruler measurement and all other ruler measurements on the same image. To show angles:

1.	Draw at least two ruler measurements.

2.	Toggle the angles on by clicking on the Show Angles button on the toolbar.

3.	Select the ruler measurement relative to which angles should be measured.

Moving and resizing the ruler will dynamically update the angles. In the case where the rulers do not intersect, dotted lines will extend from the measurements to form an intersection. If the intersection is visible onscreen, the angle between the two rulers will be displayed. If the intersection is not visible onscreen, the angles are shown in the style of a Cobb Angle.

1 The Cobb Angle is a measure of the scoliosis curvature in a patient's spine computed by measuring the angle between two specific vertebrae. As the lines drawn parallel to the vertebrae typically do not intersect onscreen, the angle is measured by drawing lines perpendicular to the original lines such that the new lines intersect onscreen. The new intersection has the same angles as the off screen intersection, a fact that can be verified readily using basic geometric axioms.