Download Radiography of the Orbits

Radiography of the Orbits
Fall 2009
FINAL
Function of Orbits
1. Serve as bony sockets for the eyeballs
2. Openings for nerves and blood vessels
Bones of the Orbits - 7
A
B
C
D
E
I
F
G
H
Division of the Orbits
1. ________________
–
Primarily composed
of orbital plate of
frontal bone
3. _______________
– Medial
•
Lacrimal
– Lateral
2. ________________
–
–
–
Zygoma (small
amount)
Maxilla
Palatine
•
Zygoma (large
amount)
Base of the Orbit
The circumference is
made of 3 bones:
1. _________________
2. _________________
3. _________________
Openings in Posterior Orbit
1. ______________
– Optic canal
– Sphenoid strut
2. ______________
3. ______________
ANGLE OF ORBITS
1. Each orbit projects
– 30 degrees superiorly
– 37 degrees toward MSP
Indications for Orbit and Eye
Radiography
1. Possible Fractures
1. Blowout
2. Tripod
3. Lefort
2. Foreign body of the eye
Mechanisms producing
Orbital Fractures
1. Auto accidents
2. Assault
3. Falls, sports, and industrial accidents
Blowout Fracture
Blowout Fracture
1. Blow to the eye
2. Orbital floor is fractured
3. Soft tissue herniates
into maxillary sinuses
4. Often have ocular injury
Ponsell, 2003
_____________________
Blowout Fracture
______________________
Tripod Fracture
1. Direct blow to
zygoma
2. Visual concave
abnormalities
3. Usually orbits are
involved
4. Free floating zygoma
Ponsell, 2003
LeFort
Fractures
LeFort types II & III
involve the orbits
Richardson, 2000
Lefort II and III
LeFort Fractures
1. Type II
1. Separation through:
 frontal processes
 lacrimal bones
 orbit floors,
 zygomaticomaxillary
suture line
 lateral wall of
maxillary sinuses
 pterygoid
1. Complications
1. ____________
system obstruction
2. Infraorbital nerve
anesthesia
3. ____________
4. Malocclusion
Lefort 2
LeFort Fractures
1. Type III
1. Complications
1. _________________
1. Separation of mid third of
face at:
 zygomaticotemporal
 naso-frontal sutures
 and across orbital floors
2. Mal-union
3. _________________
4. Lenthening of mid face
5. _________________
system obstruction
LEFORT 3
LEFORT 3
Basic and Special Projections
1. Eyes
1. Orbits
1. Basic
1. Basic
•
•
_________________
_________________
2. Special
•
_________________
•
_______________
•
_______________
•
_______________
Parietoacanthial Projection
Waters Method
1. Positioning
1. ____________
2. ____________
2. Lines and planes:
1. ____________
2. ____________
3. CR:
1. ___________
Ballinger & Frank, 1999, pg 317
Parietoacanthial Projection
Waters Method Radiograph
1. Distance from lateral
border of skull and
orbit equal on each
side
2. Petrous ridges
projected
immediately below
maxillary sinuses
Parietoacanthial Projection
Modified Waters
1. Positioning:
1. _____________
2. Lines and planes
1. _____________
2. _____________
3. CR
1. ____________
Modified Waters Radiographs
1. Petrous ridges
projected
immediately below
the inferior border of
the orbits
2. Equal distance from
lateral orbit to lateral
skull on both sides
Modified Parietoacanthial
Modified Waters method
Modified Waters
Radiograph & Diagram
Acanthioparietal Projection
Reverse Waters Method
1. Positioning
 _______________
2. Lines and planes
 _______________
 _______________
3. CR
 _______________
Ballinger & Frank, 1999, pg 320
Reverse Waters Radiograph
1. Distance from lateral
border of skull and
orbit equal on each
side
2. Petrous ridges
projected
immediately below
maxillary sinuses
Parietoorbital Projection (Rhese Method)
(PA) Optic Canal and Foramen
1. Positioning
1. ______________
2. ______________
2. Lines and planes:
1. ______________
2. ______________
3. PA- CR:
1.
enters 1”superior and
posterior to TEA
4. PA- CR:
1.
exits through the affected
orbit
Ballinger & Frank, 1999, pg 290
Parietoorbital Projection (Rhese Method)
(PA) Optic Canal and Foramen Radiograph
1.
Optic canal & foramen visible
at end of sphenoid ridge in
inferior & lateral quadrant of
orbit
2.
Entire orbital rim
3.
Supraorbital margins lying in
same horizontal plane
4.
Close beam restriction to the
orbital region
Rhese Diagram and Radiograph
Rhese Method
(AP) Optic Canal and Foramen
1. Positioning:
1. _______________
2. _______________
2. Lines and planes:
1. _______________
2. _______________
3. AP- CR:
1.
_______________
Ballinger & Frank, 1999, pg 292
Rhese Method
(AP) Optic Canal and Foramen
Radiograph
1.
Optic canal & foramen visible
at end of sphenoid ridge in
inferior & lateral quadrant of
orbit
2.
Entire orbital rim
3.
Supraorbital margins lying in
same horizontal plane
4.
Close beam restriction top
the orbital region
Rhese Radiograph and Diagram
Foreign objects in the EYE
Lateral Projection (EYE)
1. Positioning:
1. Semiprone or seated
upright
2. Affected eye closest to
cassette
3. ___________________
2. Lines and planes:
1. MSP parallel
2. IPL perpendicular
3. CR:
1. ___________________
Lateral Eye for Foreign Body
1. Density & contrast
permitting optimal
visibility of orbit and
foreign bodies
2. SI orbital roofs
3. Close beam
restriction
1. Positioning
1. Forehead & nose on
IR.
2. Center IR ¾ “ distal
to nasion
3. ________________
2. Lines and planes:
1. ________________
3. CR:
1. Through center of
orbits, 30 degrees
caudal
PA Axial (EYE)
PA Axial Eye Radiograph
1. Petrous pyramids
lying below orbital
shadows
2. No rotation of
cranium
3. Close beam
restriction
1. Positioning:
1. IR at level of orbits
2. Rest pt’s chin on IR
3. Instruct pt to close eyes
and hold eyes still
2. Lines and planes:
1. MSP perp
2. OML 50 degrees
3. CR:
1. Perp through mid-orbits
Modified Waters
(EYE)
Modified Waters Radiograph
1. Petrous Pyramids
lying well below
orbital shadows
2. Symmetric
visualization of orbits
3. Close beam
restriction
LETS REVIEW
Seven Bones of the Orbit
Openings and Supporting
Structures of Openings of the Orbit
Parietoorbital Oblique Projection of
Orbits
References
Ballinger, P.W. & Frank, E.D. (1999).
Merrill’s atlas of radiographic positions and radiologic
procedures. V2. New York: Mosby
Ponsell, M.R. (2003). Assessing facial fractures in the
emergency room. New Jersey
Richardson, M.L. (2000). Facial and mandibular fractures.
Retrieved May 5, 2007 from:
http//www.rad.washington.edu/mskbook/facialfx.html