Radiographic Surface Anatomy and Reference Points
The inferior rim of the orbit (the bony cavity of
11. Infraorbital margin
the skull that contains the eye).
Plane that divides the body into right and left
halves. Cranial reference points are external
12. Midsagittal plane
occipital protuberance (EOP) and the glabella.
Line that connects the acanthion and the
13. Acanthiomeatal line
external auditory meatus (EAM), the opening of
the ear. Also know as the occlusal plane.
Line that connects the external (outer) canthus
14. Orbitalmeatal line (OML)
of the eye and auditory meatus (EAM).
Line that connects the infraorbital margin and
the external auditory meatus (EAM). It is also
15. Infraorbitmealtal line
referred to as the Reid's base line of the
Line that connects the pupils of the eye. In a
true lateral position, the IPPL must be
16. Interpupillary line (IPPL)
perpendicular to the table.
Line that connects the glabella and the external
17. Glabellomeatal line (GML)
auditory meatus (EAM).
Line that connects the glabella and the mental
18. Gabelloalveolar line
Two or more planes of the skull are used to
ensure proper alignment, e.g., the median
19. Two-way heal alignment
plane, the facial plane, the OML, the IOML, the
AML and IPPL.
The cartilaginous projection anterior to the
external opening of the ear. (The tragus and
EAM are the same.)
Line that connects the mental point and the
21. Mental meatal line (MML)
Table 5-1. Terminology (concluded).