Transcript Anatomy, landmarks, baselines, AP, PA and

Cranium
RTEC 233
Fall 2011
Week 1
1
Human skull is made of how
many bones?
2
What are the two distinct
groups they are divided into?
3
What is the purpose of the :
facial bones?
Cranial bones?
4
Name the Cranial bones
A
B
C
D
F
E
5
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Cranial bones are further
divided into:
6
Cranial Anatomy

Calvaria

Floor
1.
1.
2.
2.
3.
3.
4.
4.
7
Name the 3 regions of the cranial
floor
1.
2.
3.
8
Regions of the Cranial Floor
9
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.
Anterior Cranium

Not able to visualize:
1.
2.

Able to visualize:
1.
2.
3.
4.
10
.
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Superior Cranium

Visualized more
clearly:





Sphenoid
Temporals
Occipital
Frontal
Not well visualized:


Ethmoid
Parietals
11
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.
Lateral Cranium
From this view which cranial bones
can you visualize?
12
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Frontal Bone

Has a vertical and horizontal portion
13
Parietal Bone
14
Occipital Bone
15
Ethmoid Bone



Horizontal portion is called cribiform plate
Vertical portion is called perpendicular plate
2 light spongy labyrinths
16
Sphenoid Bone
17
Sella Turcica

Lies in the MSP


¾” anterior & superior
to EAM
Deformity of the sella
is often the only clue
that a lesion exists
intracranially
18
Temporal Bone

Divided in 3 parts



1) __________ upper
portion forming part of
the wall of skull
2) ________ Posterior
to EAM contains
mastoid tip (process)
3) _______ dense &
houses organs of
hearing and balance


Thickest most dense
bone in cranium
Level of TEA
19
Name the four sutures:
20
Name the junctions of the
sutures:
21
Adult Sutures
and Junctions


Sutures:
 Coronal

Sagittal

Squamosal

Lamboidal
Junctions

Bregma

Lambda

Pterion

Asterion
22
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Name the fontanels and
where are they found?
23
Infant Sutures
& Fontanels

Anterior


2 Mastoids


Close approx 2 years
2 Sphenoidal


Close approx 2 years
1-3 months old
Posterior

1-3 months
24
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Lets compare
Infant
Adult

Anterior fontanel
Bregma

Posterior fontanel
Lambda

Sphenoidal fontanels
Pterions

Mastoidal fontanels
Asterions
25
Cranial Topography
26
Skull Topography
Be able to locate the following landmarks:






Glabella
Inner canthus
Outer canthus
Nasion
Infraorbital margin
Acanthion





Gonion
Mental point
External auditory
meatus (EAM)
Auricular point
Top of ear
attachment (TEA)
27
Surface
Landmarks
28
Skull
morphology
29
Skull Positioning Lines
30
Skull Positioning Lines

Interpupillary line (IPL)
a)

Acanthiomeatal line (AML)
b)

Mentomeatal line (MML)
c)
31
Skull Positioning Lines

Orbitomeatal line (OML)
a)

Infraorbitomeatal line (IOML)
b)

Glabellomeatal line (GML)
c)
32
Positioning Aids
Use any straightedge:
•Straw
•Pen/pencil
33
Most Common Positioning Errors

Rotation

Tilt

Excessive Flexion

Excessive Extension

Incorrect CR angle
Rotation
Tilt
34
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Hyposthenic
and Asthenic


Usually need
support at
chest to elevate
C-spine
Helps prevent
downward tilt
of MSP
35
Hypersthenic


Require
radiolucent
support at head
Helps prevent
upward tilt of
MSP
36
Indications for Cranial Radiography

Skull fractures

Neoplasms




Linear
Depressed
Basal skull
Metastases



Osteolytic
Osteoblastic
Combo of both

Gunshot wounds

Multiple myeloma

Pituitary Adenomas

Paget’s Disease

Subdural hematoma

Acoustic neuroma
37
Disinfect the Table or Bucky!!
38
Cleanliness


Hair and skin of face are naturally oily; illness
often increases oiliness
Cranial procedures require direct contact of
patient’s face with VBS

Clean device after each patient

Wash your hands!!!
39
Radiation Protection




Collimate to anatomy of interest
Shield gonads/abdomen of pediatric patients
and those of reproductive age
Shield thyroid and thymus of pediatric patient
when doing so will not interfere with
demonstration of anatomy of interest
Good communication and positioning skills
reduce chance of need for repeat radiographs
40
Positioning: Lateral Skull

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CR enters 2”
superior to EAM
41
Positioning Trauma Lateral Skull

CR enters
2”
superior
to EAM
42
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Lateral Skull
43
Lateral Skull Radiograph


Entire cranium without
rotation/tilt
SI orbital roofs, greater
wings of sphenoid, and
TMJ’s

Sella turcica in profile

Penetration of parietal

No overlap c-spine by
mandible
44
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Positioning PA

Central ray


0 degrees
Exits the nasion
45
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Trauma PA Skull


Direct
horizontal CR
perpendicular
Exits nasion
46
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PA Radiographs

Entire skull with no
rotation or tilt

Petrous ridges fill orbits
with horizontal beam

Density and contrast are
sufficient

No motion

Nasion in center of film,
close collimation
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47
Positioning: AP Skull
CR directed at nasion with a horizontal beam
48

Entire skull with no
rotation or tilt

Petrous ridges fill orbits
with horizontal beam

Density and contrast are
sufficient

No motion

Nasion in center of film,
close collimation

Image is magnified
compared to PA
AP Skull
Radiograph
49
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Name projection:
Positioning error:
50
What is the repeatable
positioning error?
51
Name projection:
Positioning error:
52