LESSON 5
POSITIONING FOR EXAMS OF THE CRANIUM, SINUSES, AND MANDIBLE
5-1.
SURFACE ANATOMY AND REFERENCE POINTS
There are 21 terms pertaining to surface anatomy and reference points given in
table 5-1. You will need to know these terms in order to comprehend the specifications
for the cranium projections that follow. Please take a moment to familiarize yourself
with the terms that appear in the table below and on the following page. Be sure to
refer to the graphics on the pages following the table. These graphics depict cranial
reference points.
Radiographic Surface Anatomy and Reference Points
The most superior portion of the skull
1. Vertex
The ridge or arch of the bone extending
2. Superciliary (arch)
across the forehead directly above each eye
Smooth prominence between the eyebrow
3. Glabella
The depression at the bridge of the nose
4. Nasion
The junction of the upper lip and the nasal
5. Acanthion
septum.
The angle of the mandible. The most inferior
posterior and lateral points on the external
6. Gonion
angle of the mandible.
7. External auditory meatus
The opening of the external ear canal
(EAM) (see also #20, tragus.)
The bump along the midline of the lower back
8. External occipital
of the head; also referred to as the inion.
protuberance (EOP)
The midpoint of the triangular area of the
chin; also referred to as the mental
9. Mental point
protuberance.
The lateral junction of the eyelids
10. External (outer canthus)
Table 5-1. Terminology (continued).
MD0962
5-2