Skull Radiographic Views and Anatomy Flashcards

1
Q

what are skull radiographs used for

A

assessing maxillofacial trauma

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2
Q

what are the main types of skull radiograph

A

occipitomental
postero-anterior mandible
reverse townes
true lateral skull

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3
Q

what is the difference between a lateral ceph and a true lateral skull

A

true lateral skull is not standardised using a cephalostat

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4
Q

what is special about the positioning of the skull x-ray machines

A

they can be positioned to capture the patient at different angles (even if the patient is bed bound and cannot stand up)

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5
Q

what type of receptor is used for skull x-rays

A

digital

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6
Q

what reference line is used for skull radiographs

A

orbitomeatal

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7
Q

where does the orbitomeatal line extend to

A

outer canthus of eye to centre of external auditory meatus

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8
Q

what does an occipitomental radiograph show

A

facial skeleton avoiding superimposition of skull base

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9
Q

what are occipitomental radiographs used for

A

middle third facial fractures

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10
Q

how many angles do you use for an occipitomental radiograph

A

2

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11
Q

what are the indications for an occipitomental radiograph

A

middle third fractures (le fort, zygomatic complex, naso-ethmoidal complex, orbital blow-out)
coronoid process fractures

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12
Q

how do you position a patient for an occipitomental radiograph

A

face towards receptor
head tipped back so orbitomeatal line at 45 degrees to receptor
nose-chin position

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13
Q

what does a posterio-anterior mandible radiograph show

A

posterior parts of mandible

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14
Q

why is a postero-anterior mandible radiograph not suitable for viewing the facial skeleton

A

because of superimposition of base of skull and nasal bones

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15
Q

what are the indications for a postero-anterior mandible radiograph

A

lesions and fractures involving posterior third body, angles, rami, low condylar necks
mandibular hypoplasia, hyperplasis
maxillofacial deformities

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16
Q

how do you position the patient for a postero-anterior radiograph

A

face towards receptor, head tipped forward
forehead-nose position

17
Q

why is the x-ray beam projected from the posterior part of the skull

A

reduced magnification of face = less distortion of structures
reduced effective dose = x-ray beam partly attenuated by back of skull before hitting soft tissues

18
Q

what does a reverse townes radiograph show

A

condylar heads and necks

19
Q

what is the difference between a reverse townes and a postero-anterior radiograph

A

mouth is open with reverse townes

20
Q

what are the indications for reverse townes radiograph

A

high fractures of the condylar necks
intrascapular fractures of TMJ
condylar hypoplasia/hyperplasia

21
Q

how do you position the patient for a reverse townes radiograph

A

face towards receptor
forehead-nose position
mouth open

22
Q

what does opening the mouth do in a reverse townes radiograph

A

moves the condylar heads out of the glenoid fossa