Transcript Basic skull parts 1 and 2

Skull Positioning
DMI 55
Basic Skull Positioning- Parts 1 and 2
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)
The
8 Cranial Bones are:
• 1 Frontal
• 2 Parietal
• 1 Occipital
• 1 Ethmoid
• 1 Sphenoid
• 2 Temporal
Top of skull = skull cap
= Calvarium
• It is made up of 4
bones
• Frontal
• L & R Parietal
• Occipital
Frontal bone
2 parietal bones
Occipital
Floor of Cranium
The Floor of the Cranium is made of 4 bones
(The four on the floor!)
• The Ethmoid
• The 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!
There are 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?
1 year!
What are fontanels?
Six areas of incomplete ossification in a
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
• FlexionExtension
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)
Dolichocephalic(David)
Skull Morphology
Mesocephalic(middle-average)
Microcephalic
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
e Nasion
f Acanthion
g Mentum
There are generally 5 basic positions in a
“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 the
human skull reach full size?
Would you
believe 12
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?
Rotation!- A
boo!
B
Yaah!
Compare the difference!
PA
PA Axial
What is TREPANATION?
• The intentional drilling
of holes through the
skull
• to improve mental
functions
• open up the 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 Cspine by mandible
What is wrong with this lateral?
Rotated!
Correct
Other ways to
perform Lateral-
Dorsal Decub
Semiprone
Erect
What projection and what is wrong?
R
• Caldwell
• Tilted
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?
Under-extension
of chin(Mandible not
superimposed
Over frontal bone)
Which one is the best SMV projection?
A
B
Tilted
Which SMV projection is the best?
A
-underextended!
B
?
?