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

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

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//