Table 2 Openings of the orbital cavity and rules for delineating artificial boundaries

Anterior aperture

3D surface generated from fiducial landmarks placed along the crest of the orbital rim.

Optic canal

Cropping – the posterior border of the clipping box was adjusted to coincide with the intersection of the anterior limb of the optic strut and the optic canal, as viewed in three orthogonal, slice-based views.

Inferior orbital fissure

Manually delineated - convex path of closing generated by approximating the contour of adjacent bones. Approximated using a 2D interface in SmartPaint.

Superior orbital fissure

Manually delineated – convex path of closing generated by approximating the contour of adjacent bones. Approximated using a 2D interface in SmartPaint.

Nasolacrimal canal

Manually delineated – convex path of closing generated by approximating the contour of adjacent bones. Approximated using a 2D interface in SmartPaint.

Infraorbital canal

Roof of infraorbital canal provided anatomical boundary + manual delineation of posterior entrance

Supraorbital canal

Manually delineated – convex path of closing generated by approximating the contour of adjacent bones. Approximated using a 2D interface in SmartPaint.