Basic Anatomy:
The skull encloses and protects the brain and its related
structures. It is a solid bony box with a ‘back’
consisting of the occipital and parietal bones; a
‘top’ consisting of the frontal bone and two parietal
bones joined by the saggital suture; right and left sides
consisting of the parietal and squamous temporal bones, a
‘front’ consisting of the frontal bone and facial
structures and a floor consisting of the occipital bone,
petrous temporal and sphenoid bones. The cranium is made up
of 8 bones and the facial skeleton of 14 bones, with the
exception of the mandible all are immovable and joined by
sutures. The most complex part is the base which contains
numerous foramina for the passage of arteries veins and
cranial nerves.
Lateral Skull Anatomy
Key.
1 Frontal Bone
2. Mandible
3. Maxilla
4. Zygoma
5. Greater wing of
sphenoid
6. Parietal bone
7. Squamous temporal
bone
8. Zygomatic arch
9. Mastoid process of
temporal bone
10. Occiput.
Frontal Aspect of Skull,
Key.
1. Frontal
bone
2. Mandible
3. Maxilla
4. Zygoma
5. Greater
wing of sphenoid
6. Inferior
orbital fissure
7. Superior
orbital fissure
8. Nasal
bone
Major Landmarks used for skull radiography:
1. Vertex
2. External Occipital Protuberance (E.O.P.)
3. External Auditory Meatus
4. Outer Canthus Of Eye.
5. Infra-orbital point
6. Nasion
7. Glabella
Baselines, Body Planes and Major
Landmarks
Accurate location of these lines, planes and points is
essential to ensure accurate and reproducible positioning
necessary for high quality imaging of the skull and facial
bones. Traditionally the planes and points have frequently
used peoples names E.g. Reid’s Baseline but convention
is now regarded as being as follows.
Major body planes used in Skull radiography
 |
 |
 |
| Median Saggital
|
Coronal
|
Anthropological
|
The Median Saggital plane.
A vertical plane dividing the skull into 2 symmetrical
right and left halves when viewed from the anterior
aspect.
The Anthropological plane,
This plane splits the skull into upper and lower halves passing along the anthropological
baseline lines.
The Auricular plane.
This plane divides the skull into anterior and
posterior compartments along the Auricular lines.
Major Baselines
used in Skull Radiography
 |
 |
 |
| Anthropological
|
Orbitalmeatal
|
Interpupillary |
The Anthropological
line
The Isometric “Baseline” which runs from the
inferior orbital margin to the upper border of the
external auditory meatus (EAM)
The Orbital-Meatal Line
The original “Baseline” which runs from the Nasion
through the outer
canthus of the eye to the center of the external auditory
meatus.
The Interpupillary line
The line connects the
centers of the orbits and is at 90 degree to the median saggital
plane.
The Auricular Line (No Diagram)
This line passes at 90 degrees to the anthropological line
through the center of the external auditory meatus.
Note:
there is a difference of 10 to 15 degrees between the
Orbital-Meatal line and the anthropological line.
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