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