Radiography of the Orbits Fall 2009 FINAL Function

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 • – Lateral • 2. ________ _ – – – Zygoma (small amount) Maxilla Palatine Lacrimal 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

Le. Fort Fractures Le. Fort types II & III involve the orbits Richardson, 2000

Lefort II and III

Le. Fort Fractures 1. Type II 1. Separation through: n n frontal processes lacrimal bones orbit floors, zygomaticomaxillary suture line n lateral wall of maxillary sinuses n pterygoid 1. Complications 1. ______ system obstruction 2. Infraorbital nerve anesthesia 3. ______ 4. Malocclusion

Lefort 2

Le. Fort Fractures 1. Type III 1. Complications 1. _________ 1. Separation of mid third of face at: n zygomaticotemporal n naso-frontal sutures n 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. Orbits 1. Eyes 1. Basic • • _________________ 2. Special • _______________ • ________

Parietoacanthial Projection Waters Method 1. Positioning 1. ____________ 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 n ________ 2. Lines and planes n _______________ 3. CR n ________ 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. 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. 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. V 2. 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