Skull Radiographic Views & Anatomy Flashcards
(22 cards)
What are skull radiographs?
group of plain radiographs used primarily for assessing maxillofacial trauma
What are the 4 main types of skull radiograph?
- occipitomental
- posterior-anterior mandible
- reverse Townes
- true lateral skull
What are occipitomental radiographs used for?
primarily for fractures of the mandible
What are posters-anterior mandible radiographs used for?
- fractures of the posterior mandible
- excluding condyles
What are reverse Towne’s radiographs used for?
primarily for fractures of the mandibular condyles
What equipment is required to take skull radiographs?
- x-ray equipment
- specialised skull unit
- can position patient
- standing up
- lying on back
- capture different angles
- receptor
- digital
- large to capture relevant areas
What is the orbitomeatal line?
outer canthus of eye to centre of external auditory meatus
What reference line is used for most skull radiographs?
- orbitomeatal line
What do occipitomental radiograms show?
show the facial skeleton, avoiding superimposition of the skull base
What angles can occipitomental radiographs be taken at?
- 0 degrees
- 10 degrees
- 30 degrees
- 40 degrees
- tend to use two different degree views
- 10 and 40 degrees
- may be referred to as Waters view
What are the indications for taking occipitomental radiographs?
- middle third fractures
- Le Fort I, II and III
- zygomatic complex
- naso-ethmoidal complex
- orbital blow out
- coronoid process fractures
How should a patient be positioned for an occipitomental radiograph?
- face towards receptor
- head tipped back
- orbitomeatal like at 45 degrees
- to receptor and floor
- ‘nose to chin position’
- orbitomeatal like at 45 degrees
- x-ray beam
- angled depending on type taken
- 0 degrees
- perpendicular to receptor
- centres through occiput
- 30 degrees
- 30 degrees above perpendicular
- centred through lower border orbit
What are the most important pieces of anatomy to look at on an occipitomental radiograph?
- zygomatic bone and zygomatic arch
- temporal bone
- orbital rim
- infra-orbital foramen
- maxillary sinus
- coronoid process
What does a poster-anterior mandible radiograph show?
- shows posterior parts of the mandible
- not suitable for facial skeleton
- superimposition
- skull base
- nasal bones
- vertebrae
- superimposition
What are the indications for a postero-anterior mandible radiograph?
- lesions and fractures
- posterior third of body
- angles
- rami
- low condylar necks
- medio-lateral expansion of lesion
- mandibular hypoplasia/hyperplasia
- maxillofacial deformities
How should a patient be positioned for a poster-anterior mandibular radiograph?
- face towards the receptor
- head tipped forward
- orbitomeatal line
- perpendicular to receptor
- forehead-nose position
- orbitomeatal line
- x-ray beam
- perpendicular to receptor
- centred through cervical spine
- level of rami
Why is the x-ray beam projected from the posterior aspect for skull x-rays?
- reduced magnification of face
- less distortion of relevant structures
- back of skull magnified
- less important
- reduced effective dose
- x-ray beam partly attenuated
- by back of skull
- before reaching face
- lower radiation to radiosensitive tissues
- lens of eye
- x-ray beam partly attenuated
What are the most important pieces of the anatomy to look at on a poster-anterior mandible radiograph?
- posterior mandible
What does a reverse Townes radiograph show?
- shows the condylar heads and neck
- similar to poster-anterior mandible
- different x-ray beam angle
- mouth open
- drop the condylar heads
- move out of the glenoid fossae
What are the indications for a reverse Townes radiograph?
- high fractures of the condylar necks
- intra-capsular fractures of TMJ
- condylar hypoplasia/hyperplasia
How should a patient be positioned for a reverse Townes radiograph?
- face towards receptor
- head tipped forward
- orbitomeatal line perpendicular
- to receptor
- forehead-nose position
- orbitomeatal line perpendicular
- mouth open
- moves condylar heads
- out of glenoid fossae
- x-ray beam
- 30 degrees below perpendicular line
- to receptor
- centres through condyles
- 30 degrees below perpendicular line
What are the most important pieces of anatomy to look for on a reverse Townes radiograph?
the condyles
