Radiography of the facial bones and sinuses Flashcards

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1
Q

Sinus projections

A

Occipitomental (waters/OM)
Occipitofrontal 20 (Caldwell’s/OF 20)
Lateral

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2
Q

Facial bone projections

A

Occipitomental (waters/OM)
Occipitomental 30 (waters axial/OM 30)
Occipitofrontal 20 (Caldwell’s/OF 20
Lateral)

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3
Q

Occipitomental (waters) purpose:

A

To demonstrate the upper and middle thirds of the face, including the orbital margins, frontal sinuses, zygomatic arches, maxillary sinuses

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4
Q

Occipitomental (waters) angulation/head tilt:

A

RBL should be 45 to the image receptor. Correct angulation indicated by petrous ridges being displayed in the inferior aspect of maxillary sinus

Chin lifted too far up/RBL greater than 45 to IR: Alveolar processes projected into the maxillary sinus

Chin dipped too far down/RBL less than 45 to IR: Petrous ridges creep into the maxillary sinus

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5
Q

Occipitofrontal 20 (Caldwell’s) difference between skull and sinuses

A

In radiography of skull, we angle the tube 20 degrees, but in radiography of sinuses we can not use angles (looking at fluid levels). To compensate, we angle the RBL 20 degrees up and use HB. Head is in quite a neutral position

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6
Q

Occipitofrontal 20 (Caldwell’s) purpose

A

To better visualise frontal bones and facial features

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7
Q

Occipitofrontal 20 (Caldwell’s) angulation:

A

RBL to CR angle more than 20/chin too far up: Petrous ridges below infraorbital margin

RBL to CR angle less than 20/chin too far down: Petrous ridges above inferior orbital margin.

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8
Q

Lateral purpose:

A

To demonstrate all sinus groups, especially sphenoid sinus.

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9
Q

Lateral tilt:

A

Orbital roofs should be superimposed –> to correct make sure that inter-pupillary line is perpendicular to IR.

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10
Q

Lateral rotation:

A

If there is rotation, anterior cranial cortices and greater sphenoid wings are not superimposed –> to correct ensure that the MSP is parallel with IR

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11
Q

Occipitomental 30 (waters axial) purpose:

A

To demonstrate zygomatic arches & walls pf maxillary sinus

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12
Q

Sinusitis

A
  • Look at air fluid levels
  • Air cavities SHOULD appear radiolucent in healthy sinus
  • patient must be erect
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13
Q

Maxillary tumour

A

Increased density in maxillary sinus (tumour can spread and damage infraorbital margin)

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14
Q

Polyps

A

Masses which arise from mucosal membranes of nose and paranasal sinuses

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15
Q

Black eyebrow sign/orbital emphysema:

A
  • Emphysema: collection of pockets of air within soft tissue
  • these air pockets are visible on x-ray
  • look for orbital fractures too
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16
Q

Blowout fracture

A

Occurs when there is direct impact towards orbit, the force transmission fractures the floor of the orbit

17
Q

Tripod fractrue

A

Fracture: through maxillary sinus wall, floor of orbit, and zygomatic arch

18
Q

Lefort 2 fracture

A

Fracture line which goes through: medial orbital walls, lacrimal bones, lateral aspect of maxillary antra.