Lecture 6-Skull Flashcards

1
Q

How do you acess for rotation in a Caldwell skull?

A

Look at the distance between the orbits and the side of the skull

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2
Q

Where should the petrous ridges be in a Caldwell skull?

A

Petrous ridges in lower third of orbits

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3
Q

How do you position for a PA caldwell projection?

A

-Erect PA
-MSP and OML perpendicular to IR

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4
Q

What angle is used for a PA caldwell projection?

A

15 degrees caudad

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5
Q

What angle is used for an AP caldwell projection?

A

15 degrees cephalad

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6
Q

What projection is this? What error(s) have been made?

A

-PA caldwell
-Only needed to collimate to the base of skull

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7
Q

What corrections need to be made to this iamge of the PA caldwell skull?

A

-Angle 10 degrees more caudad
-Lift the chin so the OML changes 10 degrees
-Rotate nose to the left

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8
Q

If the petrous ridges are in the middle of the orbits in a PA caldwell, what was the angle that was most likely used?

A

10 degree caudad angle

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9
Q

What corrections need to be made to this image of the PA Caldwell?

A

-Need to angle caudad an extra 5 degrees or raise the chin so that the OML changes by 5 degrees.
-Nose needs to be rotated towards the right (opp to odontoid rules)

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10
Q

What correction needs to be made to this image of the PA caldwell?

A

-Nose needs to be rotated towards the left
-Angle 10 degrees more caudad or lift the chin so OML changes by 10 degrees

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11
Q

What errors have been made to this image of the PA caldwell?

A

-Petrus ridges in a good spot
-Clipped vertex, too much of mandible on image
-Centered incorrectly

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12
Q

What would happen to the petrous ridges in this image if we were to center correctly? What would we have to do to correct this?

A

Petrus ridges would be too low, so we would have to decrease the caudad angle by 5 degrees or flex the neck so the OML changes by 5 degrees

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13
Q

What corrections need to be made to this image of the PA caldwell?

A

-Nose needs to be rotated to the right
-Petrus ridges in the middle; increase the caudad angle by 5 degrees, lift the chin 5 degrees

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14
Q

What corrections need to be made to this image of the PA caldwell?

A

-Extend the neck (looks like a Ruggles with no angle)
-Need to angle 25 degrees

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15
Q

Do we repeat for tilt in skull images?

A

No

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16
Q

Do we repeat for rotation in skull images?

A

Yes, most of the time

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17
Q

What errors have been made to this image of the PA caldwell?

A

-Vertex to the right
-Too wide FOV

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18
Q

What do we hit first in an AP Caldwell?

A

The orbits

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19
Q

What corrections need to be made to this image of the AP caldwell?

A

-Decrease the cephalad angle used (don’t need to specify the number) or tuck the chin down
-Rotate the nose to the right slightly

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20
Q

What corrections need to be made to this image of the AP caldwell?

A

-Rotate the nose towards the right
-Decrease the cephalad angle used or flex the neck

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21
Q

What corrections need to be made to this image of the AP caldwell?

A

-Center higher, collimate, and rotate nose the right

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22
Q

T/F

The waters method is done AP and PA

A

True

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23
Q

Where should the petrous ridges be in a waters method?

A

Petrous ridges below maxillary sinuses or maxillary antrum

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24
Q

What two peices of anatomy is the waters method done for?

A

Sinuses
Facial bones

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25
Q

What angle is used for the sinus waters method?

A

No angle

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26
Q

When the MML is perpendicular to the IR, what is the angle of the OML to the bucky?

A

Angle of the OML=37 degrees from the IR/bucky

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27
Q

How do you position for a sinus waters method?

A

-Have patient open mouth while maintaining OML angle of 37 degrees (MML perp.)
-Horizontal ray
-Midline – exits at acanthion
-Collimate to edge of orbits, and hairline to below open mouth

28
Q

What sinus does the waters method for the sinuses demonstrate?

A

Sphenoid sinuses are demonstrated through the open mouth.

29
Q

What is the collimation for the facial bones waters?

A

Collimate to include zygomatic arches, and hairline to include the mandible

30
Q

How do you position for a waters method for the facial bones?

A

-Erect facing IR
-Chin resting on bucky
-OML 37° from bucky
OR
-MML perpendicaular to IR
-MSP perpendicular to IR

31
Q

What is the bottom of the maxillary sinus called?

A

The antrum

32
Q

What projection is this? What errors have been made?

A

-Waters method-sinuses
-Could have collimated side to side more

33
Q

What correction needs to be made to this image of the waters sinuses?

A

-Collimate more side to side
-Need to extend the neck more (petrous ridges too high)
-Nose needs to be rotated the left
-Vertex needs to be tilted to the left

34
Q

What corrections need to be made to this image of the waters sinuses? Would this be a repeat?

A

-Need to flex the neck
-This would be a repeat because the teeth obscure the sinus

35
Q

T/F

-If petrous ridges at bottom of the maxillary sinus for a waters sinus method, we need to repeat the image

A

False-That is good positioning

36
Q

What correction needs to be made to this image of the waters sinuses?

A

-Nose needs to be rotated to the right
-Vertex needs to go to the left

37
Q

What corrections need to be made to this image of the waters sinuses?

A

-Extend the neck more
-Rotate nose the right

38
Q

What correction needs to be made to this image of the waters facial bones?

A

-Neck could be extended more

39
Q

What error has been made in this image of the waters facial bones?

A

-Tilted to the left slightly

40
Q

What correction needs to be made to this image of the waters facial bones?

A

-Need slight extension

41
Q

Is this image of the waters sinuses a repeat? Why or why not?

A

Yes because the petrous ridges are filling the maxillary sinuses

42
Q

What projection is this? What errors have been made?

A

-Lateral skull
-None; good positioning

43
Q

How do we acess for tilt in the lateral skull?

A

By looking for superimposition of the orbital plates

44
Q

Where should the TM joints and the EAM be in a lateral skull?

A

Both sides of the TM joints and the EAM should be in the same vertical plane

(should’nt be seeing two of each)

45
Q

Where should the top of the skull be in relation to the IR in a lateral skull position?

A

Top of skull parallel to top of IR

46
Q

How do we access for tilt when positioning a lateral skull (looking the patient prior to imaging?

A

Making sure the IPL is perpendicular

47
Q

How do you access for rotation on the patient in a lateral skull?

A

Making sure the MSP is parallel to IR

48
Q

T/F

To acess for rotation in a lateral skull, look at the position of the zygomatic arches.

A

False; DO NOT EVER TALK ABOUT THE ZYGOMATIC PROCESSES ON A LATERAL SKULL
-Zygomatic process are too far away so we cannot access (for every one inch, 1.5 degree difference)

49
Q

How do you acess for rotation in the image of a lateral skull?

A

Look at the condyles of the mandible

50
Q

What errors have been in this image of the lateral skull?

A

-Could have collimated more
-Tilt present (more magnified anterior and inferior); vertex was tilted towards the right

51
Q

What should the spine look like in a lateral skull position?

A

Spine should appear like an oblique

52
Q

What errors have been made in this image of the lateral skull?

A

-Top is clipped
-Neck too flexed

53
Q

What would happen if we centered higher without changing any positioning?

A

Would project the right orbital plate inferior

54
Q

What error has been made in this image of the lateral skull?

A

-Slight amount of rotation
-Chin flexed
-Shoulders not obliqued

55
Q

How do you acess for rotation and tilt in the lateral orbits?

A

By looking at the position of the zygomatic processes

56
Q

What error has been made in this image of the lateral orbits?

A

Nose rotated away from IR

57
Q

What correction needs to be made to this image of the lateral orbits?

A

-Tilt the vertex to the left
-Rotate the nose to the right

58
Q

For the AP mandible, do we want the image to look more like a ruggles or a caldwell? Why?

A

Ruggles; seeing a lot more ramus and body un superimposed

59
Q

What projection is this? What errors have been made?

A

AP/PA mandible
-None-Good image

60
Q

How should the AP/PA mandible be positioned?

A

-OML and MSP perpendicular to IR
-Perpendicular MSP– midway between EAM and syphysis menti

61
Q

What error has been made in this image of the AP/PA mandible?

A

Chin extended too much-Mandible being foreshortened

62
Q

What error has been made in this image of the lateral mandible?

A

-Nose rotated to the left-Don’t look at Z processes
-Right as to be the lower one because of the diverging beam

63
Q

What errors have been made in this image of the lateral mandible?

A

-Too wide FOV
-Vertex tilted towards the IR
-Nose rotated towards the IR

Look at the entire ramus

64
Q

What error has been made in this image of the lateral mandible?

A

None

65
Q

What correction needs to be made to this image of the lateral mandible?

A

-Center down
-Collimate

66
Q

How do you position for a lateral mandible?

A

-True lateral - IPL perpendicular to IR
-MSP parallel to IR
-IOML perpendicular to front edge of the IR