Transcript Basic Skull Projections

Skull Positioning
DMI 55
Basic Skull Positioning- Parts 1 and 2
6/5/2014
2 types of Skull bones
8 Cranial
14 Facial
-form protective housing
of brain (cranial vault)
-provides structure, shape & support
for face
-protective housing for upper ends of
respiratory & digestive tracts
- with cranial-forms eye sockets
The
Cranium
• The Brain
• Of Jane
• Stays mainly
• In her Cran(ium)
8Cranial Bones are:
• 1 Frontal
• 2 Parietal
• 1 Occipital
• 1 Ethmoid
• 1 Sphenoid
• 2 Temporal
Top of skull = skull cap
Made up of 4
bones:
Frontal
L & R Parietal
Occipital
=
Calvarium
Frontal bone
2 parietal bones
Occipital
Floor of Cranium
Floor of Cranium is made of 4 bones
(The four on the floor!)
• Ethmoid
• Sphenoid
• Left & Right
Temporal bones
1 Ethmoid Bone
1 Sphenoid
bone
2 Temporal bones
Temporal Bones
PETROUS RIDGE
LATERAL
AP
Temporal
bones
contain
the
organs of
hearing
and
balance!
14 Facial Bones
•
•
•
•
•
•
•
•
2
2
2
2
2
2
1
1
maxillary bones
nasal
lacrimal
Zygoma (malar)
palatine
inferior nasal conchae
vomer
mandible
2 Maxillary bones
2
nasal bones
2
lacrimal bones
2 Zygomas
2 Palatine bones
2 inferior nasal conchae
1 Vomer
1 Mandible
At approximately what age does the human
eyeball reach maturity?
What are fontanels?
Six areas of incomplete ossification in newborn
Sphenoidal
fontanel (pterion)
Mastoid
fontanel
(asterion)
At what age do the fontanels close?
• Posterior and
sphenoidal fontanels
close during first 1-3
months after birth
• Anterior and
mastoid fontanels
close during 2nd year
of life
Radiographic Landmarks
Radiographic Landmarks
Landmarks
Radiographic baselines
All skull positions are based on 3 factors
• Rotation
• Tilt
• Flexion-
Extension
3 types of Skull Position change
• 1st type • Rotation -your head is
rotating on an axis-your
neck
• The “NO” position
2nd type of skull position change
• Flexion-extension
• Also called “Yes”
position
Flexion
Extension
3rd type of skull position change
• Tilt
• Or “Maybe” position
Skull Morphology
Mesocephalic
Brachycephalic
Dolichocephalic
Average Skull
Skull Morphology
Brachycephalic(Broad)
Mesocephalic(middle-average)
Dolichocephalic(thin)
Review
• A-Vomer
• B-Perp.plate
ethmoid
• C-Nasion
• D- inferior
nasal conchae
• E- Anterior
nasal spine
Lateral Skull
b (suture)
bc
aA
a
i
d
e
h h
g
f
• a-sphenoid
• b-squamous
suture
• c-temporal
• d-occipital
• e-EAM
• f-mastoid
process
• g-styloid
process
• h-TMJ
• i-zygoma
Landmarks
Midsagittal plane
a
b
Outer Canthus
Infraorbitlal margin
j
Glabella
c Interpupillary line
d Inner Canthus
i
Gonion h
eNasion
f Acanthion
g
Mentum
Generally 5 basic positions in
“Skull Series”
•
•
•
•
•
PA
PA Axial (Caldwell)
Lateral
AP Axial (Towne)
SMV (Submentovertical)
• All use 40” SID and
10X12 IR
PA projection
PA projection
O degrees
• Forehead and nose touch IR
• CR perpendicular to IR (0
deg. Angle)
• Exit at nasion
• Cassette 10x12 lengthwise
Alternate PA skull projections
Decub style
AP
PA Skull- Evaluation Criteria
R
• Entire Cranium included
• Equal distance from
lateral border of skull to
lateral border of orbit
on both sides
• Symmetric petrous
pyramids filling orbits!
At approximately what age does human skull reach full
size?
___ years old?
PA Axial –Caldwell method
PA Axial-Caldwell
• Exactly same as PA,
except CR angled
15 degrees down!
PA Axial- Caldwell
Evaluation Criteria
• Same as PA except
petrous ridges fill
the lower 1/3 of
orbits!
Which PA Axial projection is best?
A
B
Compare the difference!
PA
PA Axial
What is TREPANATION?
• Intentional drilling of holes
through skull
• to improve mental functions
• open up cranial vault so
brain can once again bathe
directly in cosmic energy
that it has been sealed off
from since fontanels closed
up
Lateral projection of Skull
Lateral projection of Skull
• 10x12 CW
• CR 2” superior to EAM
• Midsagittal plane parallel to
IR
• Interpupillary line
perpendicular to IR
• (IOML parallel to long axis of
IR)
Lateral Skull- Evaluation Criteria
• Entire cranium without
tilt or rotation
• Superimposed orbital
roofs, and EAMs, TMJs
• Sella Turcica in profile
• No overlap of C-spine
by mandible
What is wrong with this lateral?
Other ways to perform Lateral
Semiprone
Dorsal Decubitus
Erect
What projection and what is wrong?
R
AP Axial-
(Towne Method)
AP Axial- Towne method
• CR 30 deg. Cauduad to
OML (37 deg to IOML)
• CR enters 2 ½” above
glabella, passing
through level EAM
AP Axial
(Towne Method)
- Evaluation Criteria
• No rotation (equal
distance from lateral border
of skull to lateral margin of
foramen magnum)
• Symmetric petrous
ridges
• Dorsum sellae and
posterior clinoids visible
in foramen
Alternate ways to perform Towne
Lateral Decubitus
Erect
Submentovertical projection
(SMV)
SMV
• CR-through Sella
turcica (3/4” anterior to
EAM) Perpendicular
to IOML
• IOML parallel to IR
• 10x12 cassette
lengthwise
SMV- alternate position
SMV- Evaluation Criteria
• Equal distance from lateral
border of skull to
mandibular condyles on
both sides (no tilt)
• Superimposition of mental
protuberance over frontal
bone
• Mandibular condyles
anterior to petrous
pyramids
What’s wrong with this SMV projection?
Which is best SMV projection?
A
B
Which SMV projection is the best?
A
B
?
?