Skull Radiographic Views And Anatomy

Question 1

What are most skull radiographs taken with?

Answer 1

An isocentric skull unit such as the Orbix

Question 2

What are the landmarks for the orbitomeatal baseline?

Answer 2

Outer canthus of eye
External auditory meatus

Question 3

What line is used for reference when lining up a patients head for an X-ray of the skull?

Answer 3

The orbitomeatal baseline

Question 4

What are the main maxillofacial/skull projections?

Answer 4

Occipitomental
Postero- anterior mandible
Reverse Towne’s
True lateral skull

Question 5

What does a standard occipitomental radiograph show?

Answer 5

Shows the facial skeleton and maxillary antra
Avoids superimposition of the dense bones of the base of the skull

Question 6

What are the main indications of a standard occipitomental radiograph?

Answer 6

Middle third facial fracture
Coronoid process fracture
Investigation of maxillary antra
Investigation of frontal and ethmoidal sinuses
Investigation of sphenoidal sinus

Question 7

Explain the technique and positioning when taking a standard occipitomental radiograph

Answer 7

Pt faces image receptor with head tipped back
OM baseline should be 45° to image receptor (nose-chin position)
X-ray tube head is positioned with central ray horizontal centred through occiput

Question 8

What is the difference between a standard occipitomental radiograph and a 30° occipitomental radiograph?

Answer 8

30° occipitomental radiograph Shows a different angle, enabling certain bony displacements to be detected

Question 9

What are the main indications for taking a 30° occipitomental radiograph?

Answer 9

Middle third facial fracture (Le Fort I, II, III)
Coronoid process fractures

Question 10

Which middle third facial fractures indicate the need for a standard occipitomental radiograph?

Answer 10

Le Fort I, II, III
Zygomatic complex
Naso- ethmoidal complex
Orbital blow-out

Question 11

Which 2 radiographs are required in the case of a suspected facial fracture?

Answer 11

Standard occipitomental radiograph
30° occipitomental radiograph

Question 12

Explain the technique and positioning of the pt when taking a 30° occipitomental radiograph

Answer 12

Pt faces image receptor with head tipped back
OM baseline should be 45° to image receptor (nose-chin position)
X-ray tube head is positioned with central ray at 30° to the horizontal centred through the lower border if the orbit

Question 13

What does a PA skull radiograph show?

Answer 13

Shows the skull vault, primarily the frontal bones and the jaws

Question 14

what are the main indications of a PA skull radiograph?

Answer 14

investigation of frontal sinuses
conditions affecting the cranium e.g. Paget’s disease, multiple myeloma, hyperparathyroidism
intracranial calcification

Question 15

explain the technique and positioning of the pt when taking a PA skull radiograph

Answer 15

pt facing the image receptor with head tipped forward (forehead-nose position)
the radiographic baseline is horizontal and at right angles to the image receptor
X-ray tube is positioned with the central ray horizontal centred through the occiput

Question 16

what does a PA mandible radiograph show?

Answer 16

the posterior parts of the mandible

Question 17

why is a PA mandible radiograph not suitable for showing the facial skeleton?

Answer 17

because of superimposition of the base of the skull and the nasal bones

Question 18

what are the main clinical indications of a PA mandible radiograph?

Answer 18

fractures of the mandible involving angles, rami, low condylar necks or posterior third of the body
lesions such as cysts or tumours in the posterior third of the body or rami to note any mediolateral expansion
mandibular hypoplasia or hyperplasia
maxillofacial deformities

Question 19

explain the technique and positioning of the pt when taking a PA mandible radiograph

Answer 19

patient’s head tipped forward
radiographic baseline horizontal and perpendicular to the image receptor (forehead-nose position)
x-ray. tubehead is horizontal with the central ray centred through the cervical spine at the level of the rami of the mandible

Question 20

what does a reverse Towne’s radiograph show?

Answer 20

the condylar heads and necks

Question 21

what are the main clinical indications for a reverse Towne’s radiograph?

Answer 21

high fractures of the condylar necks
intracapsular fractures of the TMJ
investigation of the quality of the articular surfaces of the condylar heads in TMJ disorders
condylar hypoplasia or hyperplasia

Question 22

explain the technique and positioning of the pt when taking a reverse Townes radiograph

Answer 22

patients head tipped forward in the forehead-nose position, with the mouth open
radiographic baseline is horizontal and at right angles to the image receptor
X-ray tube is aimed upwards and below the occiput, with the central ray at 30o to the horizontal, centred through the condyles

Question 23

why is the pt asked to open their mouth during a reverse Townes radiograph?

Answer 23

opening the mouth takes the condylar heads out of the glenoid fosse so they can be seen

Question 24

what is a rotated posteroanterior (roared PA) radiograph used for?

Answer 24

to investigate the parotid gland and the rams of the mandible

Question 25

what are the main indications of a rotated PA radiograph?

Answer 25

stones/calculi in the parotid gland lesions such as cysts or tumours in the rams to note any medic-lateral expansion submasseteric infection

Question 26

what does a true lateral skull radiograph show?

Answer 26

the skull vault and the facial skeleton from the lateral aspect

Question 27

what is the difference between a true lateral skull radiograph and a true cephalometric lateral skull taken on the cephalostat?

Answer 27

the true lateral skull is not standardised or reproducible

Question 28

when would you take a true lateral skull radiograph?

Answer 28

when a single lateral view of the skull is required but not in orthodontics or growth studies

Question 29

what are the main clinical indications for taking a true lateral skull radiograph?

Answer 29

fractures of the cranium and cranial base middle third facial fractures investigation of frontal, sphenoidal and maxillary sinuses conditions affecting the skull vault conditions affecting the sella turcica such as a tumour of the pituitary gland in acromegaly

Question 30

what does a submentovertex (SMV) radiograph show?

Answer 30

base of the skull sphenoid sinuses facial skeleton from below

Question 31

what are the main clinical indications of a submentovertex (SMV) radiograph?

Answer 31

investigation of the sphenoidal sinus assessment of the thickness of the posterior part of the mandible before osteotomy fracture of zygomatic arches investigating the skull base

Question 32

name a contraindication of a submentovertex radiograph

Answer 32

patients with suspected neck injuries, especially suspected fracture of the odontoid peg