skull positioning

Question 1

CR angle for AP Axial (Towne)

Answer 1

30 caudad to OML ~or~ 37 caudad to IOML

Question 2

CR centering for AP Axial (Towne)

Answer 2

2.5 inches above the glabella

Question 3

Part position for AP Axial (Towne)

Answer 3

OML perpendicular to IR ~or~ IOML if patient is unable to flex

Question 4

Image analysis for AP Axial (Towne)

Answer 4

-petrous ridges should be symmetric (indicating no rotation)
-under-angulation of CR/insufficient flexion of neck = dorsum sellae superior to foramen magnum
-over-angulation of CR/excessive neck flexion = posterior arch of C1 over dorsum sellae within the foramen magnum and foreshortening of dorsum sellae

Question 5

Correct CR angle and proper neck flexing in the Towne Method are indicated by __________ visualized in the ___________

Answer 5

Dorsum sellae and posterior clinic processes, foremen magnum

Question 6

With AP Axial (Towne) images, under-angulation of CR/insufficient flexion of neck puts ___________________

Answer 6

dorsum sellae superior to the foramen magnum

Question 7

With AP Axial (Towne) images, over-angulation of CR/excessive flexion of neck puts ___________________

Answer 7

posterior arch of C1 over the dorsum sellae within the foramen magnum and produces foreshortening of the dorsum sellae

Question 8

With AP Axial (Towne) method, the petrous ridges will appear ______ in the direction of rotation

Answer 8

narrowed

Question 9

CR angle for Lateral Skull

Answer 9

perpendicular to IR

Question 10

CR centering for Lateral Skull

Answer 10

2 inches superior to EAM ~or~ halfway between glabella and inion for other types of skull morphologies

Question 11

Part position for Lateral Skull

Answer 11

-MSP parallel to IR with no rotation or tilt
-IPL perpendicular to IR
-IOML perpendicular to front edge of IR

Question 12

_____________ is only position to see air/fluid level in trauma for a lateral skull

Answer 12

horizontal beam (cross table beam)

Question 13

rotation in a lateral skull image is evident by ______________

Answer 13

anterior and posterior separation of symmetric vertical bilateral structures (such as mandibular rami, greater wings of sphenoid)

Question 14

tilt in a lateral skull is evident by ____________________

Answer 14

superior and inferior separation of symmetric horizontal structures (such as orbital plates and greater wings of sphenoid bone)

Question 15

anatomy demonstrated in a lateral skull

-entire cranium
-superimposed __________
-entire sella turcica including ____________________
-_________________ demonstrated in profile

Answer 15

-parietal bones
-anterior/posterior clinoid processes and dorsum sellae
-sella turcica and clivus

*okay to not have entire mandible

Question 16

Part position for PA Axial (Caldwell)

Answer 16

OML perpendicular to IR, MSP perpendicular to IR

Question 17

CR angle for PA Axial (Caldwell)

Answer 17

15 caudad (to exit at nasion)

Question 18

CR centering for PA Axial (Caldwell) 15 degrees caudad

Answer 18

exit at nasion

Question 19

How to tell the difference between a PA Caldwell and AP Caldwell

Answer 19

Orbits will be magnified on an AP (due to OID magnification)

Question 20

Part position for PA Skull

Answer 20

OML perpendicular to IR, MSP perpendicular to IR

Question 21

CR angle for PA skull

Answer 21

0 (perpendicular)

Question 22

CR centering for PA skull

Answer 22

exit at glabella

Question 23

Patient position for SMV

Answer 23

hyperextend neck to get IOML parallel to the IR, rest head on vertex, MSP perpendicular to CR

Question 24

CR angle for SMV

Answer 24

perpendicular to IOML

Question 25

CR centering for SMV

Answer 25

1 ½ inch below mandibular symphysis ~or~ midway between gonions (approx. 2/4 inch anterior to level of EAM)

Question 26

Example of AP Axial (Towne) rotation: left petrous ridges narrowed means the head was rotated towards the _______

Answer 26

left, as petrous ridges appear narrowed in the direction of rotation

Question 27

In an AP Axial (Towne) image, unequal petrous ridges is indicative of (tilt/rotation)

Answer 27

rotation

Question 28

In an AP Axial (Towne) image, shifting of the anterior or posterior clinoid processes laterally within foramen magnum is indicative of (tilt/rotation)

Answer 28

tilt

Question 29

in a lateral skull, do you need to have the entire mandible on the x-ray?

Answer 29

no

Question 30

clinical indications for AP Axial (Towne)

Answer 30

skull fractures (medial and lateral displacement), neoplastic processes, Paget disease

Question 31

clinical indications for lateral skull

Answer 31

skull fractures, neoplastic processes, Paget disease

Question 32

clinical indications for PA Axial (Caldwell) skull

Answer 32

skull fractures, neoplastic processes, Paget disease

Question 33

clinical indications for PA (straight) skull

Answer 33

skull fractures (medial and lateral displacement), neoplastic processes, Paget disease visualizes frontal bone with minimal distortion

Question 34

anatomy demonstrated for PA Axial (Caldwell)

Answer 34

frontal bone, greater and lesser sphenoid wings, superior orbital fissures, frontal and anterior ethmoid sinuses, supraorbital margins, crista galli

Question 35

PA Axial (Caldwell) image will result in the petrous ridges in what part of the orbits?

Answer 35

lower 1/3 of orbits

Question 36

PA (straight) skull mage will result in the petrous ridges in what part of the orbits?

Answer 36

filling the orbits

Question 37

where does a 25-30 degree Caldwell exit?

Answer 37

also at nasion

Question 38

what does a 25-30 degree Caldwell demonstrate?

Answer 38

in addition to typical Caldwell: foramen rotundum adjacent to each IOM, superior orbital fissures within the orbits

Question 39

A 25-30 Caldwell will demonstrate ___________________ better than a typical Caldwell will

Answer 39

superior orbital fissures, foramen rotundum, inferior orbital rim

Question 40

what impacts the location of petrous ridges within the orbits for Caldwell exams?

Answer 40

CR angle and OML alignment

Question 41

Unequal distance from mid-lateral orbital margins to lateral cortex of cranium on a Caldwell exam is indicative of (tilt/rotation)

Answer 41

rotation

Question 42

Example of PA Axial (Caldwell) rotation: if the distance between the lateral orbit and lateral cranial cortex is greater than the left side, the face is rotated ______

Answer 42

toward the left side

Question 43

Correct positioning for a PA Axial (Caldwell) exam will show petrous ridges in the __________ of orbits and the _____________ visualized without superimposition

Answer 43

lower 1/3 of orbits, supraorbital orbital margins

Question 44

PA Axial (Caldwell) 25-30 degrees will result in the petrous ridges in what part of the orbit?

Answer 44

at or just below the IOM to allow visualization of entire orbital base

Question 45

clinical indications for SMV

Answer 45

advanced bony pathology of inner temporal bone structures (skull base), possible basal skull fracture

Question 46

correct extension of neck and relationship between IOML and CR are indicated by the ___________ being ___________

Answer 46

mandibular mentum being anterior to the ethmoid sinuses

Question 47

in an SMV, unequal distances between mandibular ramus and lateral cranial cortex is indicative of (tilt/rotation)

Answer 47

tilt

Question 48

Example of SMV tilt: if the distance on the left side between the ramus and lateral cranium is greater on the L than the R, the cranial vertex is tilted to the ____

Answer 48

left

Question 49

anatomy demonstrated on SMV -foramen _____________ -mandible -_________________ sinuses -______ process -petrous ridges -hard palate -foramen _______ -_______ bone

Answer 49

-foramen ovale and spinonum -mandible -sphenoid and posterior ethmoid sinuses -mastoid -petrous ridges -hard palate -foramen magnum -occipital bone

Question 50

*need PA straight skull added