Extra Oral Radiography Flashcards
1
Q
What is the technique for an Oblique Lateral?
A
- Cassette placed against the side of interest.
- Patient’s head rotated to the side of interest.
- Patient’s chin raised.
- X-ray tube positioned on opposite side to area under study behind the angle, aiming
at the region of interest.
2
Q
What should you look for when assessing an Oblique Lateral?
A
- Check the condition of any teeth shown.
- Look at the level of periodontal bone.
- Is the outline of the ID canal clear ?
- Check that the cortical outline is intact.
- In trauma cases, search systematically for fractures.
- Before injection of contrast in sialography look for calculi.
3
Q
What are the indications for Oblique Lateral radiographs?
A
- Assessment of the presence and/or position of unerupted teeth
- Detection of fractures of the mandible
- Evaluation of lesions or conditions affecting the jaws including cysts, tumours, giant cell lesions, and other bone lesions
- As an alternative when intraoral views are unobtainable because of severe gagging or if the patient is unable to open the mouth or is unconscious
- As specific views of the salivary glands or TMJ
4
Q
When should Postero-anterior (PA) jaws be requested?
A
- When a view of the the posterior aspect of the mandible is required and may reveal:
- Fractures of the condylar necks, rami, angles, and posterior body of the mandible.
- Medial-lateral expansion or destruction caused by large cysts or malignant lesions.
- Mandibular hypo/hyperplasia.
5
Q
What is the technique for Postero-anterior (PA) jaws?
A
- Cassette positioned vertically in front of the patient’s face,
- Patient’s head tipped forward in the “nose-forehead” position,
- X-ray tube horizontal and centred through the cervical spine at level of the mandibular angles.
6
Q
What should you look for on Postero-anterior (PA) jaws?
A
- In trauma cases search for fractures and note the direction of any fracture lines.
- Is the lingual plate intact? Compare with the other side.
- Check for any expansion or erosion of the lingual plates.
7
Q
When should you request an Occipito-mental (OM) view?
A
- This provides an excellent view of the maxillary sinuses and bones of the mid-face and so is commonly used to:
- assess the maxillary sinuses
- detect fractures of the zygomatico maxillary complex including the orbital margins
8
Q
What is the technique for an Occipito-Mental (OM) view?
A
- The cassette is positioned vertically in a holding device in front of the patient’s face,
- The patient’s head is tipped backwards 45 degrees to the horizontal in the “nose-chin” position,
- The X-ray tube is positioned parallel to the floor, the central ray entering just above the occiput.
9
Q
What are Campbell’s lines?
A
Campbell’s Lines:
- ZF suture-frontal sinus-ZF suture
- Arch-I/O margin x2-Arch
- Condyle-lat & med antral walls x2-condyle
- Ramus-maxillary alveolus-ramus
- Angle-body-symphysis-body-angle
10
Q
What should you look for on an Occipito-Mental (OM) view?
A
- Separation of the zygomaticofrontal sutures. Fluid in the frontal sinus.
- Check the contour of the zygomatic arches. Look for fractures of the infra-orbital margin and deviation of the nasal septum.
- Check for fractures of the medial & lateral antral walls, as well as for fluid in the sinuses.
- Look for fractures of the mandibular ramus (rare), as well as the contour of the maxillary alveolus (Le Fort I fracture).
- Look for fractures of the angles and body of the mandible.
11
Q
Indications for an Occipito-Mental (OM) view?
A
- For view of the orbital floor and zygomatic arch.
- Investigation of maxillary antra
- Detecting the following middle third facial fractures:
- Le Fort I
- Le Fort II
- Le Fort III
- Zygomatic complex
- Naso-ethmoidal complex
- Orbital blow-out - Coronoid process fractures
- Investigation of frontal and ethmoidal sinuses
- Investigation of sphenoidal sinus (projection needs to be taken with the patients mouth open)
- It is usually requested in conjunction with a standard occipito-mental film in the evaluation of trauma.
12
Q
What are the indications for an Occipito-Mental 30 (OM30) view?
A
- This provides an excellent view of the orbital floor and zygomatic arch.
- It is usually requested in conjunction with a standard occipito-mental film in the evaluation of trauma.
13
Q
What is the technique for an Occipito-Mental 30 (OM30) view?
A
- The cassette is positioned as for the standard OM view,
- The patient’s head is tipped backwards 45 degrees to the horizontal in the “nose-chin” position,
- X-ray tube is aimed downwards from above the head, centred through the lower orbital border, at 30 degrees to the horizontal
14
Q
What should you look for on an Occipito-Mental (OM30) view?
A
- Follow the guidelines for the standard OM.
- Pay attention to the orbital floor and the zygomatic arches.
15
Q
What are the indications for a Lateral Skull View?
A
This provides a view of the skull vault, the paranasal sinuses and the sella turcica so can be used to detect:
- Fractures of the cranium and skull base
- Displacement of middle third facial fractures
- Frontal, sphenoid and maxillary sinus disease
- Disease which may affect the skull vault (Paget’s, multiple myeloma, hyperparathyroidism)
- When a pituitary tumour is suspected
