Orbits and Nasal Views

Question 1

LATERAL Nasal Positioning

Answer 1

-Table top/nongrid
-Planes and Lines:
-MSP is || to IR
-IPL is ⟂ to IR
-IOML is || to transverse axis of IR
-CR:⟂ to bridge of nose at a point 0.5” distal to nasion
-Collimation: 3x3” with marker in light field
-Instructions: Suspend

Question 2

LATERAL Nasal Evaluation Criteria

Answer 2

Nasal bones, anterior nasal spine, frontonasal suture

Question 3

Bones that make up the orbit

Answer 3

7:
• Maxillary
• Frontal
• Zygomatic
• Ethmoid
• Lacrimal
• Sphenoid
• Palatine
“Many Friendly Zebras Enjoy Lazy Summer Picnics”

Question 4

Labeling of the orbits

Answer 4

A: Optic Foramen
B: Superior Orbital Fissure
C: Inferior orbital Fissure

Question 5

The long axis of each orbit is directed obliquely posteriorly medially at an angle of __ degrees to the MSP and superiorly at an angle of __ degrees from the OML

Answer 5

37, 30

Question 6

What view is best for orbital blow out fractures?

Answer 6

Waters

Question 7

Optimal image quality requires:

-Reducing geometric unsharpness by using minimal _____ and a ____ focal spot
size.
-Minimize secondary radiation by close ___
-Eliminate ___ by having the patient gaze ___ at a fixed object
-Minimize ___ by cleaning the IRs.

Answer 7

-OID, Small
-Collimation
-Motion, steadily
-Artifacts

Question 8

LATERAL Orbits Positioning

Answer 8

-Planes and Lines:
-MSP is || to IR
-IPL is ⟂to IR
-IOML is ⟂ to the front edge of the IR
-CR: ⟂ to the outer canthus
-Collimation: 3x3” with marker in light field
-Instructions: Look straight ahead, suspend

Question 9

LATERAL Orbits Evaluation Criteria

Answer 9

-Entire orbits
-Superimposed orbital roofs

Question 10

PA AXIAL Exaggerated Caldwell Orbits positioning

Answer 10

-Planes and Lines:
-MSP is ⟂ to IR
-OML is ⟂ to IR
-CR: 30 degree caudal through center of orbits
-Collimation: to orbits with marker in light field
-Instructions: Close eyes and concentrate on holding still, Suspend

Question 11

PA AXIAL Exaggerated Caldwell Orbits Evaluation Criteria

Answer 11

-Entire orbits
-Petrous pyramids lying below orbital shadow due to our 30 degree angulation
-No rotation
-Symmetric visualization of the orbits
-Close beam restriction centered to orbital region
-Brightness and contrast permitting optim visibility of the orbit and eye for localization of foreign bodies

Question 12

PARIETOACANTHIAL(Modified waters) Orbits Positioning

Answer 12

-Planes and Lines:
• MSP is perpendicular to IR
• OML forms 50° angle with plane of the IR
-CR: perpendicular to mid-orbits
-Collimation: to orbits with marker in light field
-Instructions: Close eyes, concentrate on holding still, Suspend

Question 13

PARIETOACANTHIAL(Modified waters) Orbits Evaluation Criteria

Answer 13

-Entire orbits
-Petrous pyramids lying below orbital shadows
-No rotation
-Symmetric visualization of the orbits
-Close beam restriction centered to orb region
-Brightness and contrast permitting op visibility of the orbit and eye for localization of foreign bodies

Question 14

PARIETAL ORBITAL (RHESE) Positioning

Answer 14

-Planes and Lines:
• 3 point landing: chin, nose, and cheek
• MSP forms 53 degrees to IR
• AML is ⟂ to IR
-CR: ⟂ entering 1” superior and posterior to upside TEA attachment (exiting downside orbit)
-Collimation: to orbit with marker in light field
-Instructions: Suspend

Question 15

PARIETAL ORBITAL (RHESE) Evaluation Criteria

Answer 15

-Structures Demonstrated:
-Optic canal “on end” and optic foramen lying in the inferior and lateral quadrant of orbit
Lateral deviation- incorrect MSP rotation
Longitudinal deviation- incorrect AML angulation
-Parietoorbital projection of ethmoid, sphenoid and frontal sinuses

Evaluation Criteria
-Optic canal & foramen visible at end of sphenoid ridge (inferior & lateral quadrant)
-Entire orbital rim

Question 16

For Nasal PA AXIAL where does the CR exit?

Answer 16

Nasion

Question 17

For Orbits WATERS where does the CR exit?

Answer 17

The orbitals