Skull Radiographs And Anatomy Flashcards
What is the reference line used in skull radiographs
Orbitomeatal line
From the outer canthus of the eye to the centre of the external auditory meatus
What is the most common skull radiograph used for facial fractures
Occipitomental radiograph
Why is Occipitomental radiograph so good for facial fractures
Because of the positioning it avoids superimposition of the skull base
What is the main indication for Occipitomental radiographs
Middle third facial fractures
What is the positioning for Occipitomental radiograph
Head tipped backed so that Orbitomeatal line is 45drgees to the receptor
Nose-chin postion
What is a posters-anteior mandible radiograph mainly used for
This is used for viewing the Posterior part of the mandible and any fractures or abnormalities there
Why is a PA mandible not suitable for viewing facial skeleton
This is because of the superimposition of the skull and nasal bones
If you suspected a fracture in the posteior third or the angle of the mandible what radiograph would you want?
PA mandible
What is the positioning for a PA mandible radiograph
Head tipped forwards so that the Orbitomeatal line is perpendicular to the receptor
Forehead - nose postion
Why is the X-ray beam projected from the postioer side in skull radiographs
Reduced magnification of the face so less distortion of relavent structures
Reduced effective dose, xray is partly attenuated by the back of skull before reaching the face causing less radiation dose to more radiosentive tissue
What does a reverse Townes radiograph show?
Shows condylar heads and neck with expect fracture or abnormality
What is the difference with a PA mandible and a reverse Townes radiograph
Mouth the open is a reverse Townes
Why do we want the mouth open in a reverse Townes radiograph?
This is because we are wanting to view the condylar heads and to do this effectively we need them to be out of the glenoid fossa so they can be viewed
What is the positioning of reverse Townes radiograph
Head tipped forward so that the Orbitomeatal line is perpendicular to the receptor
Forehead - nose postion
