The document provides a comprehensive overview of panoramic imaging in regard to anatomical structures and their unique projections, highlighting peculiarities in image interpretation. It covers various concepts including the projection of midline structures, ghost images, and the presentation of soft tissue and air spaces. Additionally, it identifies common errors in patient preparation and positioning that can impact the quality of the radiographic image.

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CONTENTS
 Concepts
 Errors

3. A CONCEPTUAL APPROACH TO UNDERSTANDING THE
PANORAMIC IMAGE
• A number of peculiarities of the panoramic system result in a unique projection of many
anatomic structures in the image.
• This produces numerous anatomical relationships in the image that are not found in any
other kind of radiographic projection.
• These peculiarities must be understood to accurately interpret pathologic conditions as they
differ from normal structures.
3

4. CONCEPT 1: STRUCTURES ARE FLATTENED AND SPREAD OUT
The jaws and structures of the maxillofacial complex as well as the spine are portrayed as
if they were split vertically in half down the mid- sagittal plane with each half folded
outwards such that
 the nose remains in the middle
 the right and left sides of the jaws are on each side of the film
 the spine, having been split in half, appears beyond the rami at the extreme right
and left hand edges of the film.
4

5. 1. The midline of the film corresponds to the anterior midline of the patient and that the
right and left hand edges of the film correspond to the posterior midline of the patient
2. The right and left halves of the jaws and maxillofacial complex side by side on the
film without one half being superimposed on the other and without the distortions that
normally occur in plain films when one side is projected out of the image as in the
lateral jaw view.
DESIRABLE EFFECTS
5

6. UNDESIRABLE EFFECTS
1. When the patient is improperly positioned in the machine.
For example, when the chin is tipped too low and the patient is positioned a little back in the
machine, the hyoid bone is spread out and projected up, right on top of the mandible. In the
same way, the tubinates and meati of the nose are spread out projected across the maxillary
sinus.
6

7. CONCEPT 2: MIDLINE STRUCTURES MAY BE PROJECTED AS SINGLE
IMAGES AND DOUBLE IMAGES
• A real image is formed when the object is located between the rotation center of the beam
and the film .
• An object will be portrayed with minimal unsharpness and distortion when it is close to
the plane at the center of the layer.
• It will be portrayed with considerable unsharpness and distortion when it is far away from
this plane.
7

8. 8

9. The regions where real images are formed
relative to typical continuous movement
patterns
9

10. 10

11. A double image is a pair of real images
formed by an object lying within the
diamond shaped zone where points are
intercepted twice by the beam
11

12. 12

13. 13

14. * Structures that produce double images include the hard palate, palatal tori, the body of the
hyoid bone and the epiglottis.
⁕ When the patient is positioned too far back in the machine:
The turbinates and meati enter into the diamond area, and double images are produced.
These spread across the maxillary sinus, the greater horns of the hyoid bone, which are
spread across the mandible.
⁕ When the patient is positioned too far forward:
The spine enters into the diamond area and is projected as a double image on the film and
sometimes it is superimposed on the styloid process, ramus, and TMJ areas.
14

15. 15

16. CONCEPT 3: GHOST IMAGES ARE FORMED
A ghost image is formed when the object is located between the x-ray source and the center of
rotation.
16

17. 17

18. Ghost images have the following characteristics:
1. The ghost image has the same morphology as its real counterpart.
2. The ghost image appears on the opposite side of the radiograph from its real counterpart.
3. The ghost image appears higher up on the radiograph than its real counterpart.
4. The ghost image is more blurred than its real counterpart.
5. The vertical component of a ghost image is more blurred than the horizontal component.
6. The vertical component of a ghost image is always larger than its real counterpart while the
horizontal component of a ghost image mayor may not be severely magnified.
18

19. 19

20. o In the vertical dimension the ghost image appears higher than the real image
since structural details lying between the radiation source and the rotation center are
projected at higher levels than structural details at the same height, which lie between
the rotation center and the film
o For objects producing ghost images between the x-ray source and the rotation center
blurring is especially severe, since the shadows and the film are actually moving in
opposite directions relative to the beam.
20

21. 21

22.  Narrow structures are more severely affected by motion blurring than are wide
structures, because the shadow of a narrow structure, moving a distance with
respect to the film that is large relative to its width, will have its density "spread
out“.
 The vertical, narrow details almost vanish from sight
 The horizontal, wide details are clearly portrayed.
22

23. o Panoramic radiographs are characterized by different magnification factors for the
horizontal and vertical dimensions.
o The magnification factors in the two dimensions are equal for those structures lying in
the sharply depicted plane at the center of the layer.
o The vertical magnification factor increases continually as an object is moved closer and
closer to the x-ray source.
o The horizontal magnification factor increases greatly close to the rotation center of the
beam.
23

24. • In the vertical dimension the ghost image will always appear larger than its real
counterpart.
• The horizontal dimension may be more or less magnified than the vertical
dimension depending upon the location of the object between the center of
rotation and the x-ray source.
24

25. Anatomic structures that are often ghosted :
⁕ The hyoid bone
⁕ The cervical spine
⁕ Inferior border of the mandible
⁕ Posterior border of the ramus
⁕ The meati
⁕ The turbinates
Other objects that ghost are:
* chin rest
* right and left markers of some machines
* earrings, napkin chains, neck chains
* the shoulder straps of protective aprons
25

26. 26

27. CONCEPT 4: SOFT TISSUE OUTLINES ARE SEEN
Soft tissue structures visible in the radiograph are:
• The posterior and superior regions where there are no teeth and in all regions of
edentulous patient
• Fluids and cartilaginous tissues such as the ear, nose, and epiglottis
• The soft palate and uvula
• Dorsum of the tongue
• Posterior pharyngeal wall
27

28. • Lips
• Nasolabial fold
• Soft tissue of the nasal turbinates
• Septum
• Retromolar pad
• Operculum of erupting teeth
28

29. 29

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1. Tongue: A radiopaque area superimposed over the maxillary posterior teeth.
2. Soft palate and uvula: A diagonal radiopacity projecting posteriorly and inferiorly from
the maxillary tuberosity region.
3. Lip line:
• The lip line is seen in the region of the anterior teeth.
• The areas of the teeth not covered by the lips appear more radiolucent.
• The areas of the teeth covered by the lips appear more radiopaque.
4. Ear:
• A radiopaque shadow that projects anteriorly and inferiorly from the mastoid process.
• The ear is viewed superimposed over the styloid process.

31. CONCEPT 5: AIR SPACES ARE SEEN
The air spaces that may be seen include:
• Hypopharynx
• Oropharynx
• Nasopharynx
• The maxillary sinus
• Nasal fossa
• Mastoid air cells
• External auditory canal
• Ethmoid sinuses
31

32. * If an air space noted above the dorsum of the tongue: the periapical region of the maxilla
will be difficult to interpret and can be avoided by asking the patient to place his tongue
taken.
* If an air space is noted in the region of the against the palate while the radiograph is being
anterior teeth, the crowns of these teeth will be difficult to interpret and can be avoided by
asking the patient to close his lips around the bite block during the exposure.
* When the soft tissue outlines of the turbinates are projected across the maxillary sinus, the
patient probably has been placed too far back in the machine, causing the turbinates to
enter into the diamond area and produce double images 32

33. 33

34. 34
1. Palatoglossal air space: A horizontal radiolucent band located above the apices of the
maxillary teeth.
2. Nasopharyngeal air space: A diagonal radiolucency located superior to the radiopaque
shadow of the soft palate and uvula.
3. Glossopharyngeal air space: A vertical radiolucent band superimposed over the
ramus of the mandible. It is continuous with the nasopharyngeal air space superiorly and
the palatoglossal air space inferiorly.

35. CONCEPT 6: RELATIVE RADIOLUCENCIES AND RADIOPACITIES ARE SEEN
⁕ In any image it is important to separate shadows originating from parts of the machine and
those coming from the patient.
⁕ Machine components seen in the image are made of plastic, have a density similar to that
of soft tissue and are usually easy to identify due to their geometric or linear configuration.
⁕ The patient may be thought of as being made up of three basic components:
hard tissue (teeth and bone), soft tissue (including cartilage and fluid),air
⁕ If an area of hard tissue is intersected by an air space, it will appear relatively more
radiolucent than an adjacent area that is interrupted by a soft 35

36. To obtain the ideal single real image of the patient's three basic tissue components:
identify all other shadows that can be caused by
• Machine components
• Double images
• Ghosts
36

37. If a pathologic process is present, it will consist either of hard tissue or soft tissue, and it will
affect one or more of the three tissue components in the patient as follows:
1. Those conditions producing hard tissue will cause all three patient components to become
relatively more radiopaque in the region of the disorder.
2. A soft tissue pathologic condition within the mineralized component causes it to become
more radiolucent, whereas the soft tissue and air components become more radiopaque
when a soft tissue disorder is present.
3. When a soft tissue lesion encroaches upon an airspace such as the nasopharynx or
maxillary sinus it be- comes visible as an opacity superimposed on the air space. 37

38. 38
Relative radiolucencies and radiopacities
1. The ramus is relatively more radiolucent due to superimposition of the nasopharyngeal
airspace
2. The oral and nasopharyngeal airspaces are interrupted by a soft tissue mass consisting of a
hyperplastic palatine tonsil
3. The airspace of the oropharynx
4. The soft tissue of the earlobe superimposed on the airspace of the nasopharynx

39. 39
5. The hyperplastic adenoid tonsil causes the condylar neck and head to appear relatively
more radiopaque and the upper portion of the nasopharyngeal airspace to appear relatively
radiopaque
6. The artifactual palatoglossal airspace obliterates bony details in the apical region of all of
the upper teeth and represents an error in technique
7. Soft tissue of the base of the tongue.

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The uniqueness of the panoramic technique is that it results in an excellent projection
of a variety of structures on a single film which no other imaging system can achieve.
CONCEPT 7: PANORAMIC RADIOGRAPHS ARE UNIQUE

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ZONES OF INTERPRETATION

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The panoramic image was divided into six anatomical zones for anatomical structure evaluation.
Nomenclature for each zone is defined as
֎ Zone 1: Dentition
֎ Zone 2: Nasal and Sinus
֎ Zone 3: Mandibular Body
֎ Zone 4: Temporal-mandibular Joint
֎ Zone 5: Ramus-spine
֎ Zone 6: Hyoid Bone

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BONY LANDMARKS OF THE
MAXILLA AND SURROUNDING
STRUCTURES

44. 44
1. Mastoid Process A rounded radiopacity located posterior and
inferior to the temporomandibular joint.
2. Styloid process A long radiopaque spine extending from the
temporal bone anterior to the mastoid process.
3. External auditory meatus (External acoustic
meatus)
A round to oval radiolucency anterior and
superior to the mastoid process.
4. Glenoid fossa (Mandibular fossa) A concave radiopacity superior to the mandibular
condyle.
5. Articular eminence (Articular tubercle) A rounded radiopaque projection of the bone
located anterior to the glenoid fossa.
6. Lateral pterygoid plate A radiopaque projection of bone distal to the

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7. Pterygomaxillary fissure A radiolucent area between the lateral pterygoid
plate and the maxilla.
8. Maxillary tuberosity A radiopaque bulge distal to the third molar region.
9. Infraorbital foramen A round or oval radiolucency inferior to the orbit.
10. Orbit A round radiolucent compartment with radiopaque
borders located superior to the maxillary sinus
11. Incisive canal (Nasopalatine canal) A tube like radiolucent area with radiopaque
borders.
12. Incisive foramen (Nasopalatine foramen) A small ovoid or round radiolucency located
between the roots of the maxillary central incisors.

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13. Anterior nasal spine A “V” shaped radiopaque area located at the inter-section of the
floor of the nasal cavity and the nasal septum.
14. Nasal cavity A large radiolucent area above the maxillary incisors.
15. Nasal septum A vertical radiopaque partition that divides the nasal cavity.
16. Hard palate A horizontal radiopaque band superior to the apices of the
maxillary teeth.
17. Maxillary sinus A paired radiolucencies located above the apices of the
maxillary premolars and molars.
18. Floor of the maxillary sinus The floor of the maxillary sinus is composed of dense cortical
bone and appears as a radiopaque line.

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19. Zygomatic process of the maxilla A “J’ or “U” shaped radiopacity located superior to the
maxillary first molar.
20. Zygomatic arch Posterior extension of Zygoma. Formed by Temporal
process of Zygomatic bone (Anterior 1/3) and Zygomatic
process of Temporal bone (Posterior 2/3).
21. Zygoma A radiopaque band that extends posteriorly from the
zygomatic process of the maxilla. It is triangular in shape.
22. Hamulus A radiopaque hook-like projection posterior to the
maxillary tuberosity area.
23. Dentition

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BONY LANDMARKS OF THE
MANDIBLE AND SURROUNDING
STRUCTURES

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1. Mandibular condyle A bony rounded, radiopaque projection extending from the posterior
border of the ramus of the mandible.
2. Coronoid notch A radiolucent concavity located distal to the coronoid process on the
superior border of the ramus.
3. Coronoid process A triangular radiopacity posterior to the maxillary tuberosity region.
4. Mandibular foramen A round or ovoid radiolucency centered within the ramus of the
mandible.
5. Ramus Shadows of other structures may be superimposed over the
mandibular ramus area
6. Lingula An indistinct radiopacity anterior to the mandibular foramen.
7. Mental foramen A small ovoid or round radiolucency located in the apical region of the

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8. Mandibular Or Inferior alveolar
canal
A radiolucent band outlined by two thin radiopaque lines
representing the cortical walls of the canal.
9. Mental ridge A thick radiopaque band that extends from the
mandibular premolar region to the incisor region.
10. Mental fossa A radiolucent area above the mental ridge
11. Lingual foramen A small radiolucent dot located inferior to the apices of
the mandibular incisors
12. Genial tubercles A ring shaped radiopacity surrounding the lingual
foramen.
13. Inferior border of the mandible A dense radiopaque band that outlines the lower border

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14. Mylohyoid ridge A dense radiopaque band that extends downward and forward from
the molar region.
15. Internal oblique ridge A dense radiopaque band that extends downward and forward from
the ramus
16. External oblique ridge A dense radiopaque band that extends downward and forward from
the anterior border of the ramus of the mandible
17. Angle of the mandible A radiopaque bony structure where the ramus joins the body of the
mandible
18. Dentition
19. Hyoid Bone Bilateral, ‘U’ shaped radiopaque body, just below or at the level of the
inferior border of the mandible in line with molars

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COMMON ERRORS

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PATIENT PREPARATION ERRORS

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These can include:
● Failure to remove jewellery
– Earrings, Necklaces, Piercings
● Failure to remove dentures
● Failure to remove orthodontic appliances
● Failure to remove spectacles
● Inappropriate use of the lead apron.

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PATIENT POSITIONING ERRORS

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i. Positioning of the lips and teeth:
If the lips are not closed on the bite block, a dark radiolucent shadow obscures the anterior
teeth.
ii. Positioning of the Frankfurt plan
a. Upward:
If the patient's chin is positioned too high or tipped up (i.e. the chin is too far forward while
the forehead is titled towards the back):

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– The hard palate and the floor of the nasal cavity appear superimposed over the roots of the
maxillary teeth.
– Loss of density in the middle of the radio-graph, usually characterized by an hour glass
shape.
– There is a loss of detail in the maxillary incisor region, magnification.
– The maxillary incisors appear blurred and magnified.
– Loss of one or both condyles at the side of the film.
– A 'reverse smile line' is seen on the radiograph (flattening of the occlusal plane).

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Frankfort plane not horizontal (chin tipped up)
creating out-of-focus upper incisors and
distorted occlusal plane (arrowed) (so-called
grumpy face).

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b. Downward
Ala-tragus line greater than 5° downward, the patient's chin is positioned too low or is
tipped down (i.e. chin positioned back and the forehead is positioned forward);
– The mandibular incisors appear blurred.
– There is a loss of detail in the anterior apical region of the mandible. The apices of the
lower incisors are out of focus and blurred.
– The condyles may not be visible, as they may be cut off at the top of the radiograph.

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– Shadow of the hyoid bone is superimposed on the anterior aspect of the
mandible.
– Premolars are severly overlapped.
– An 'exaggerated smile line' is seen on the radiograph (severe curvature of the
occlusal plane).

61. 62
iii. Positioning of the teeth:
a. Anterior to the focal trough :
Patient's head is positioned too far forward.
– If the anterior teeth are not positioned in the groove of the bite block, the teeth appear blurred.
– If the teeth are positioned too far forward on the bite block, the anterior teeth appear 'skinny'
and out of focus (Blurred and narrow).
– Spine is superimposed on the ramus areas.
– Premolars are severely overlapped.

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Patient positioned too far forwards (too close to
the image receptor) and frankfort plane not
horizontal (chin tipped down) creating narrow,
out of focus anterior teeth, distorted occlusal
plane (so-called smiley face) and excessive
peripheral spinal shadowing.

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b. Posterior to the focal trough:
Patient's head is positioned too far back
– If the anterior teeth are not positioned in the groove of the bite block, the teeth appear
blurred.
– If the teeth are positioned too far back on the bite block, the anterior teeth appear 'fat' and
out of focus (blurred and wide).
– Excessive ghosting of mandible and spine.

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Patient positioned too far back (too far away from the
image receptor) creating widened, magnified and out
of focus anterior teeth.

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Frankfort plane not horizontal (chin tipped down) creating out of focus lower
incisors and excessive ghosting shadows of the contralateral angles of the
mandible.

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iv. Positioning of the midsagittal plane:
If the patient's head is not centered, the ramus and the posterior teeth appear unequally
magnified. The side farthest from the film appears magnified and the side closest to the film
appears smaller.
a. Patient's head is tilted to one side.
– The side tilted towards the X-ray tube is enlarged.
– One condyle appears larger than the opposite one, the neck also appears longer on the larger
side.
– Image appears to be tilted, one angle of the mandible is higher than the other.

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b. Patient's head is twisted to one side causing the mandible to fall outside the image layer,
(one side is in front of the image layer while the other side is behind the image layer).
– Teeth on one side of the midline appear wide and have severe overlapping of contacts,
whereas the teeth on the other side appear very narrow.
– Ramus on one side is much wider than the other side.
– Condyles differ in size.

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Patient asymmetrical, rotated to the RIGHT.
The RIGHT molars are closer to the image
receptor and smaller, the LEFT molars are
further away from the image receptor and
larger

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c. Whole head is off center position (patient biting the block off center with lateral incisors
or cuspids).
– The molar teeth and the mandibular ramus are magnified on the side farther from the film.
– Anterior teeth are blurred with overlapping

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v. Positioning of the spine:
If the patient is not sitting or standing with a straight spine, the cervical spine appears as a
pyramid shaped radiopacity in the center of the film and obscures diagnostic information.
Failure to position the neck correctly – extension of the neck
causing excessive spinal ghosting shadows over the anterior
teeth.

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vi. Patient's shoulder touching the cassette during exposure:
This will slow the cassette rotation, resulting in prolonged exposure or completely stop the
film movement.
– Produces a dense black band, which is the area of overexposure or a dense black edge
may be seen at the end of the radiographic image, due to eventual stoppage of rotation.

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vii. Position of patient's tongue during exposure
If the tongue is not fully placed against the roof of the mouth.
– A dark shadow appears in the maxilla below the palate, and the apices of the maxillary
incisors are obscured.
Patient positioned too far forwards (too close to the
image receptor) creating narrowed incisors and failure
to instruct patient to keep their tongue in contact with
the palate creating the radiolucent band across the film

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viii. Distortion due to patient movement:
a. Movement in the same direction as the beam.
– There is prolonged exposure of the same area, with increase in horizontal dimension of the
image.
Continuous shaking movements throughout the cycle

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b. Movement in the opposite direction as the beam.
– The horizontal dimension of the image in the region is decreased.
c. Sudden jerky movement in the same direction as the beam.
– The area may be portrayed twice.
d. Sudden jerky movement in the direction opposite the beam movement.
– A part of the object may be missing in the image.
e. If the patient moves up or down during exposure.
– Indentation in the lower border of the mandible (mimicing a fracture)
– Blurring and unsharpness.

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Sudden movement in the vertical plane – distortion of the
image 45 region creating a step-deformity in the lower border
Movement in the vertical plane caused by the patient
opening their mouth causing distortion in the 43 region

76. 77
Multiple vertical movements while the anterior teeth
were being imaged.
Sudden side-to-side horizontal movement while the
anterior teeth were being imaged causing them to be
blurred.

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Horizontal movement towards the end of the cycle
causing horizontal elongation and stretching of the
shadow of the developing lower right third molar

78. 79
EQUIPMENT POSITIONING ERRORS

79. 80
2. Cassette positioning errors:
i. Patient's shoulders touching the cassette during the movement in the exposure cycle.
This may happen if the patient has a short neck and well developed shoulders.
– Alternating vertical dark and light bands appear on the radiograph due to improper
movement of the cassette behind the slit in the cassette holder or the tube head cassette
holder assembly around the patient's head.
ii. Cassette placed too high.
– Lower border of the mandible is cut off.

80. 81
iii. Cassette placed too low.
– Diagnostic information in the maxilla will be cut off.
iv. Two exposures on a single film.
Undiagnostic radiograph, with unnecessary exposure to the patient.
v. Cassette placed backwards.
– This is common in panorex the X-rays must penetrate the metal latch, which will present as
a radiopaque broad horizontal line through the middle of the radiograph

81. 82
The X-ray tubehead and image receptor carriage
assembly positioned too low relative to the patient – the
antra and condyles are not imaged.
Cassette positioned back-to-front in the carriage
assembly. Name plate and hinge screws are evident

82. 83
Modern cassette positioned back-to-front
Cassette inadvertently used twice and double-
exposed.

83. 84
Error and Cause Identifying Features Correction
Patient too far
forward
Narrow blurred anterior teeth with
pseudospace
Superimposition of spine on ramus
Bicuspid overlap bilaterally
Use incisal bite guide
Line up incisal edge of teeth
with notch
Edentulous patients should bite
about 5 mm behind notch
Patient too far
back
Wide, blurred anterior teeth
Ghosting of rami; spread-out turbinates,
ears, and nose in image; condyles off lateral
edges of film
Use incisal bite guide
Line up incisal edge of teeth
with notch

84. 85
Chin tipped too
low
Excessive curving of the occlusal plane
Loss of image of the roots of the lower anterior
teeth
Narrowing of the intercondylar distance and loss of
head of the condyles at the top of the film
Tip chin down, but ala-
tragus line should not
exceed —5 to — 7°
downward
Use chin rest
Chin raised too
high
Flattening or reverse curvature of occlusal plane
Loss of image of the roots of the upper anterior
teeth
Lengthening of intercondylar distance and loss of
head of the condyles at the edges of the film
Hard palate shadow wider and superimposed on the
apices of the maxillary teeth
Tip chin down —5 to
—7°
Use chin rest.

85. 86
Head twisted Unequal right-left magnification particularly
teeth and ramus
Severe overlap of contact points and blurring
Line up patient’s midline with
middle of incisal bite guide
Close side guide
Head tilted Mandible appears tilted on film
Unequal distance between mandible and chin
rest at a given point on the right and left sides
One condyle is higher and larger than the other
Position the chin firmly on
both sides of the chin rest
Close side guide
Slumped position Ghost image of cervical spine superimposed
on the anterior region
Stand-up machines: have the
patient step forward or place
feet on markers

86. 87
Chin not on the
chin rest
Sinus not visible on the film
Top of condyles are cut off
Excessive distance between inferior border
of the mandible and the lower edge of the
film
Position the chin on the chin
rest
Bite guide not
used
Incisal and occlusal surfaces of the upper
and lower teeth overlapped
Use bite guide
Compensate for missing
anterior teeth with cotton rolls
Tongue not on
palate
Relative radiolucency obscuring apices of
the maxillary teeth (palatoglossal air space)
Place the tongue firmly against
the palate
Ask the patient to swallow or
suck on his or her tongue

87. 88
Lips open Relative radiolucency on the coronal
portion of the upper and lower teeth
Close lips
Patient movement Wavy outline of cortex of the interior border
of the mandible
Blurring of the image above wavy cortical
outline
Ask the patient to hold still and
not swallow
Explain the function of the
machine to avoid startling the
patient
Be certain the patient’s clothing
will not interfere

88. 89