Assessing the Correlation between Skeletal and Corresponding Soft-Tissue Equivalents to Determine the Relationship between CBCT Skeletal/Dental Dimensions and 3D Radiographic Soft-Tissue Equivalents

Table 2

Definition of landmarks used for measuring specific distances, depending on the imaging modality used.

	Landmark	Description of landmark on CBCT	Description of landmark on soft tissue
1	Sides of nose	Left/right bottom most skeletal corner under the nasal aperture	Left/right alar curvature (most lateral part of the curved base of the ala)
2	Canine	Most tip of the left/right canine crown	Most tip of the left/right canine crown
3	Outer eye	Left/right frontozygomatic suture	Left/right lateral canthus
4	Gnathion	Lowest point of the midline of the mandible	Lowest point of the midline of the mandible
5	Throat	C3-C4 cervical vertebrae location	Most indented location of the throat between the chin and neck
6	Gonion	Most posterior and lateral point of the left/right mandibular angle	Most posterior and lateral point of the left/right mandibular angle on the skin
7	Cheekbone	Most prominent frontal portion of the left/right zygomatic bone	Most prominently raised point of the left/right cheek area, most likely an area under the left/right lateral canthus
8	Nasion	Distinctly depressed area between the intersection of the frontal bone and two nasal bones	Distinctly depressed area directly between the eyes and superior to the bridge of the nose
9	External auditory meatus (EAM)	Lowest bony portion of the left/right hollow canal of the tympanic portion of the temporal bone, posterior to the condylar processes of the mandible	Left/right lowest portion of the hollow ear canal
10	Corners of mouth	Tip of left/right canine crowns	Left/right cheilion (left/right labial commissures)
11	Bottom of nose	Anterior nasal spine	Subnasale (midpoint of the angle at the nasal base where the lower border of the nasal septum and upper lip surface meets)
12	Inner eye	Left/right frontomaxillary suture	Left/right medial canthus