Transcript Slide 1 - El Camino College

Radiography of the Orbits
Ballinger & Frank, 1999, pg 291
Function of Orbits

Serve as bony sockets for the eyeballs

Openings for nerves and blood vessels
Division of the Orbits

Roof


Floor




Primarily composed of -orbital plate of frontal bone
Zygoma (small amount)
Maxilla
Palatine
Two Walls

Medial


Lacrimal
Lateral

Zygoma (large amount)
Bones of the Orbits - 7
Base of the Orbit

The circumference


or circular base
Made of 3 bones

Frontal (cranial bone)



Maxilla ( facial bone)


Orbital plate
Forms most of the roof
Helps form the floor
Zygoma (facial bone)

Forms part of the lateral
wall and some of the floor
Openings in Posterior Orbit

Optic Foramen




Optic canal
Sphenoid strut
Superior Orbital
Fissure
Inferior Orbital
Fissure
ANGLE OF ORBITS

Each orbit projects


30 degrees superiorly
37 degrees toward MSP
Indications for Orbit and Eye
Radiography

Possible Fractures

Foreign body of the eye
Mechanisms producing
Orbital Fractures

Auto accidents

Assault

Falls, sports, and industrial accidents
Blowout Fracture




Blow to the eye
Orbital floor is
fractured
Soft tissue herniates
into maxillary sinuses
Often have ocular
injury
Ponsell, 2003
Tripod Fracture



Direct blow to
zygoma
Visual concave
abnormalities
Usually orbits are
involved
Ponsell, 2003
LeFort Fractures
LeFort types II and III involve the orbits
Richardson, 2000
LeFort Fractures

Type 3

Separation of mid third of
face at
zygomaticotemporal, nasofrontal sutures, and across
orbital floors

Complications

Non-union

Mal-union

Malocclusion

Lenthening of mid face

Lacrimal system
obstruction
LeFort Fractures

Type II

Complications


Separation through
frontal processes,
lacrimal bones, orbit
floors,
zygomaticomaxillary
suture line, lateral wall
of maxillary sinuses,
and pterygoid

Lacrimal system
obstruction
Infraorbital nerve
anesthesia

Diplopia

malocclusion
Basic and Special Projections

Orbits

Basic



Parietoorbital
(Rhese Method)
Parietoacanthial
(Waters method)
Special

Modified
Parietoacanthial
(Modified Waters
method)

Eyes

Basic

Lateral

PA Axial

Modified
Parietoacanthial
(Modified Waters
method)
Parietoacanthial Projection
Waters Method





Tip of extended chin on
grid device
OML 37 degrees from
plane of cassette
MSP perpendicular to
cassette
MML perpendicular to
cassette
CR exits acanthion
Ballinger & Frank, 1999, pg 317
Parietoacanthial Projection
Waters Method Radiograph


Distance from lateral
border of skull and
orbit equal on each
side
Petrous ridges
projected immediately
below maxillary
sinuses
Modified Parietoacanthial Projection
Modified Waters



OML 55 degree angle
from plane of IR
MSP perp
CR perpendicular and
exits acanthion
Modified Parietoacanthial Projection
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 Projection
Modified Waters method
Modified Waters
Radiograph & Diagram
Acanthioparietal Projection
Reverse Waters Method




Patients chin up and neck
adjusted so the OML is 37
degrees from cassette
MML perpendicular to
cassette
MSP perpendicular to
cassette
CR enters acanthion
Ballinger & Frank, 1999, pg 320
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

3 point landing





Zygoma, nose, and chin
AML perpendicular to cassette
MSP forms a 53 degrees angle
from cassette
PA- CR enters 1”superior and
posterior to TEA
PA- CR exits through the
affected orbit
Ballinger & Frank, 1999, pg 290

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 Method
(AP) Optic Canal and Foramen

3 point landing

Zygoma, nose, and chin

AML perpendicular to
cassette

MSP forms a 53 degrees
to cassette

AP- CR enters uppermost
orbit at inferior lateral
quadrant
Ballinger & Frank, 1999, pg 292
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)

Use non-grid high resolution
technique

Semiprone or seated upright

Affected eye closest to
cassette

MSP parallel with plane of IR

Instruct pt to look straight
ahead

IPL perpendicular to IR

CR: Perp through outer
canthus
Lateral Eye for Foreign Body

Density & contrast
permitting optimal
visibility of orb it and
foreign bodies

SI orbital roofs

Close beam restriction






Non-grid high
resolution technique
Forehead & nose on
IR.
Center IR ¾ “ distal
to nasion
MSP & OML perp
Eyes closed & held
still
CR: Through center of
orbits, 30 degrees
caudal
PA Axial (EYE)
PA Axial Eye Radiograph



Petrous pyramids
lying below orbital
shadows
No rotation of
cranium
Close beam restriction
Modified Waters (EYE)

IR at level of orbits

Rest pt’s chin on IR



MSP perp and OML 50
degrees from IR
CR: Perp through midorbits
Instruct pt to close eyes
and hold eyes still
Modified Waters Radiograph



Petrous Pyramids
lying well below
orbital shadows
Symmetric
visualization of orbits
Close beam restriction
LETS REVIEW
Seven Bones of the Orbit
Seven Bones of the Orbit







A. Frontal bone- orbital
plate
B. Sphenoid bone
C. Palatine bone
D. Zygomatic bone
E. Maxillary bone
F. Ethmoid bone
G. Lacrimal bone
Openings and Supporting
Structures of Openings of the Orbit
Openings and Supporting
Structures of Openings of the Orbit

A. Optic Foramen

B. Sphenoid Strut


C. Superior Orbital
Fissure
D. Inferior Orbital
Fissure
Parietoorbital Oblique Projection of
Orbits
Parietoorbital Oblique Projection of Orbits




A. Frontal bone- orbital
plate
B.Sphenoid bone
C. Optic foramen & canal
D. Superior orbital fissure




E. Inferior orbital fissure
F. Sphenoid strut
G. Lateral orbital margin
H. Superior orbital margin
Orbital anatomy Review

http://www.uth.tmc.edu/radiology/test/er
_primer/face/images/wtrs02.html
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