Cranium Flashcards Preview

Radiographic Positioning > Cranium > Flashcards

Flashcards in Cranium Deck (220):
1

The skull is divided into two main sets of bones:

8 cranial bones and 14 facial bones

2

The 8 bones of the cranium are divided into:

the calvarium (skullcap) and the floor. Each consist of four bones.

3

The skullcap consists of which four bones?

Frontal, right parietal, left parietal and occipital

4

The floor of the cranium consists of which four bones?

Right temporal, left temporal, sphenoid, and ethmoid.

5

This bone contributes to the formation of the forehead and the superior part of each orbit:

Frontal bone.

6

The squamous portion of any the frontal bone is the ______ portion.

vertical.

7

The orbital portion of the skull is the ______ portion.

horizontal.

8

This is the smooth, raised prominence between the eyebrows just above the bridge of the nose:

Glabella.

9

This is the slight depression above each eyebrow:

The supraorbital groove (SOG).

10

Why is the supraorbital groove an important landmark?

It corresponds to the floor of the anterior fossa of the cranial vault, which is also at the level of the orbital plate or at the highest level of the facial bone mass.

11

The superior rim of each orbit is the :

supraorbital margin (SOM).

12

This is a small hole or opening within the SOM slightly medial to its midpoint:

Supraorbital notch (foramen.).

13

On each side of the squamous portion of the fontal bone above the SOG is a larger, rounded prominence termed the:

Frontal turberosity (eminence).

14

These form the superior part of each orbit:

Orbital plates.

15

Each orbital late is separated from the other by the:

ethmoidal notch.

16

The frontal bone articulates with which four cranial bones?

Right and left parietals, sphenoid, and ethmoid.

17

The lateral walls of the cranium and part of the roof are formed by two:

parietal bones.

18

The widest portion of the entire skull is located between the:

parietal tubercles (eminences) of the two parietal bones.

19

Each parietal bone articulates with these five cranial bones:

frontal, occipital, temporal, sphenoid, and opposite parietal.

20

The inferoposterior portion of the skullcap is formed by:

the single occipital bone.

21

The external surface of the occipital bone presents a rounded part called the:

squamous portion.

22

The squamous portion of the occipital bone forms most of the back of the head and is the part of the occipital bone that is superior to the:

external occipital protuberance, or inion.

23

The large opening at the base of the occipital bone through which the spinal cord passes is called the:

foramen magnum.

24

These oval processes with convex surfaces on each side of the foramen magnum are called the:

occipital condyles

25

The occipital bone articulates with these six bones:

Two parietals, two temporals, sphenoid and atlas.

26

The right and left temporal bones house what?

the delicate organs of hearing and balance.

27

Extending anteriorly from the squamous portion of the temporal bone is an arch of bone termed:

the zygomatic process.

28

____ and _____ have largely replaced conventional radiography for imaging of mastoids and petrous pyramids.

CT and MRI

29

The mastoids and petrous pyramids are locations for organs of:

hearing and equilibrium.

30

The three divisions of the ear are:

External
Middle
Internal

31

The parts of the external ear include:

The auricle, tragus, EAM, Mastoid process, mastoid tip, and styloid process.

32

The function of the tympanic membrane is to:

transmit sound vibrations.

33

The tympanic membrane is part of the:

*middle* ear

34

The three parts of the middle ear are:

Tympanic membrane, tympanic cavity, auditory ossicles

35

The partition between the external and middle ear is the:

tympanic membrane.

36

The space between the tympanic membrane and the bony labyrinth is called:

the tympanic cavity.

37

The tympanic cavity communicates with the nasopharynx by ________.

the eustachian tube.

38

The tympanic cavity is further divided into two parts:

tympanic cavity proper, which is opposite the eardrum, and epitympanic recess, which is the area above the level of the EAM and eardrum.

39

The bony projection to which the tympanic membrane is attached:

Drum crest. (separates EAM from epitympanic recess)

40

The passageway between the middle ear and the nasopharynx is:

the eustachian tube.

41

The eustachian tube equalizes pressure within:

the middle ear to the outside air.

42

The eustachian tube is a direct connection between:

the middle ear and nasopharynx, which allows disease organisms direct passage from throat to middle ear.

43

What is smaller in diameter than the EAM and difficult to demonstrate on conventional radiographs?

The internal acoustic meatus (IAM)

44

Another direct communication with the middle ear besides the eustachian tube is:

the mastoids.

45

The aditus is:

the opening between the epitympanic recess and the mastoid portion of the temporal bone.

46

The aditus, or the opening between the epitympanic recess and mastoid, allows infection in the middle ear, which may have originated in the throat, to pass to the:

mastoids. Infection is then separated from brain tissue by only thin bone.

47

Auditory ossicles transmit sound vibrations from:

tympanic membrane to sensory apparatus of hearing in the internal ear.

48

The auditory ossicles are named:

Malleus (hammer), Incus (anvil), Stapes (stirrup).

49

Describe how the auditory aussicles articulate between the tympanic membrane to the sensory apparatus of hearing in the internal ear:

The handle of the malleus is attached to the tympanic membrane and the head of the malleus articulates with the incus. The head of the stapes articulates with the incus and its base fits into the oval window of the inner ear.

50

The inner ear contains:

sensory apparatus of hearing and equilibrium within the densest portion of the petrous pyramids.

51

The inner ear is divided into two parts:

The osseous (bony) labyrinth and the membranous labyrinth.

52

The osseous labyrinth is a bony chamber that houses:

the membranous labyrinth.

53

The membranous labyrinth is a series of:

intercommunicating duts and sacs.

54

The osseous labyrinth is divided into three distinctly shaped parts:

the cochlea, the vestibule, and the semicircular canals.

55

The cochlea communicates with:

the middle ear through the round window.

56

The vestibule is the central portion of the osseous labyrinth that communicates with:

the middle ear by way of the oval window.

57

The semi-circular canals are located:

posterior to the other inner ear structures and are named according to their position (anterior, posterior and lateral.)

58

The cochlear and vestibular nerve pass through the IAM from:

respective parts of the membranous labyrinth to the brain.

59

The semi-circular canals relate to _______, and the cochlea relates to ________.

the sense of direction or equilibrium, the sense of hearing.

60

The oval window receives vibrations from:

the external ear through the stapes of the middle ear.

61

The oval window transmits vibrations to

vestibule of inner ear.

62

The round window is located at:

the base of the cochlear.

63

The round window allows movement of:

fluid within the closed duct system of the membranous labyrinth.

64

The oval window moves slightly _____ with a vibration.

inward

65

The round window moves _____ with a vibration.

outward

66

Vibrations and slight fluid movements within the cochlea produces:

impulses that are transmitted to the auditory nerve within the IAM, creating a sense of hearing.

67

SMV projection:

from inferior aspect of the mandible, in superior direction.

68

Long axis of orbit projects superiorly ___ degrees and projects medially ____ degrees.

30 and 37.

69

The base of the orbit is made of three bones:

The orbital plate of the frontal bone, and the zygoma and maxilla bones.

70

The orbits are composed of ___ cranial bones and ____ facial bones.

3 and 4

71

Which cranial bones help make up the orbits:

Ethmoid, frontal and sphenoid.

72

Which facial bones help make up the orbits?

Lacrimal, maxillary, palatine, and zygomatic.

73

Openings in the orbit include:

Optic foramen and superior orbital fissure separated by the sphenoid strut, and the inferior orbital fissure.

74

Which of the following facial bones is unpaired?
Maxillary
Palatine
Lacrimal
Vomer

Vomer

75

The anterior nasal spine is an aspect of the _____ bone.
Maxillary
Zygomatic
Mandibular
Inferior nasal conchae

Maxillary

76

The palatine process is an aspect of the _____ bone.
Lacrimal
Maxillary
Palatine
Zygomatic

Maxillary

77

Lacrimal is derived from a word meaning:
Water
Oil
Tear
Duct

Tear

78

Which facial bone forms an aspect of the bony nasal septum?
Nasal
Maxillary
Ethmoid
Vomer

Vomer

79

What is the name of the process of the mandible in which the lower teeth are embedded?
Frontal process
Alveolar process
Body
Mental symphysis

Alveolar process

80

The older term "antrum of Highmore" describes the:

maxillary sinuses

81

Which paranasal sinus is the last one to develop?

Ethmoid

82

The posterior aspect of the bony orbit is termed the:

Apex

83

Which of the following bones makes up most of the lateral wall of the orbit?
Maxillary
Lacrimal
Zygomatic
Vomer

Zygomatic

84

What passes through the optic foramen?

The optic nerve

85

Plain radiographs will show presence or absence of skull fractures but won't indicate _______.

underlying brain injury. A CT/MRI is performed to assess brain tissue.

86

Linear fractures of the skull appear as:

jagged or irregular lucent lines that lie at right angles to the axis of the bone.

87

Depressed fractures of the skull looks like:

a fragment of bone is separated and depressed into the cranial cavity. Also called ping pong fractures.

88

What view may be used to determine the degree of depression of a depressed fracture if CT is not available?

Tangential.

89

Basal skull fractures are

fractures through the dense inner structures of the temporal bone.

90

Why are basal fractures difficult to visualize on plain radiographs?

Because of the complexity of the anatomy in the temporal bone.

91

A finding suggestive of a basal skull fracture is:

an air fluid level in the sphenoid sinus on a horizontal beam lateral.

92

Complications of basal skull fracture:

Leakage of CSF
Meningitis
Damage to facial nerve
Damage to auditory apparatus.

93

Gunshot wounds can be visualized by plain images that typically are performed to:

localize bullets in gunshot victims in an antemortem or postmortem examination.

94

Neoplasms are:

new and abnormal growths.

95

Metastases are:

primary malignant neoplasms that dread to distant sites via blood and the lymphatic system. They can be characterized as osteolytic, osteoblastic or a combination of both.

96

Osteolytic lesions are:

destructive lesions with irregular margins.

97

Osteoblastic lesions are:

proliferative bony lesions of increased density.

98

Combination osteolyic and osteoblastic lesions appear:

“moth eaten” due to mix of destructive and blastic lesions

99

Describe multiple myeloma?

Consist of one or more bone tumors that originate in bone marrow.
Skull is a common affected site.

100

What does a pituitary adenoma look like on a radiograph?

enlargement of sella turcica and erosion of dorsum sellae

101

How does Paget’s disease (osteitis deformans) present on a radiograph?

Areas of lucency demonstrate destructive stage.
“Cotton-wool” appearance with irregular areas of increased density shows reparative stage.

102

Describe Mastoiditis:

Bacterial infection that can destroy inner part of mastoid process. Air cells are replaced with fluid-filled abscess.
Can lead to hearing loss.

103

What modality best shows the fluid filled abscesses of mastoiditis?

CT

104

Describe an Acoustic Neuroma:

Benign tumor (neoplasm) of auditory nerve.
Originates in IAC.
Symptoms: hearing loss, dizziness and loss of balance.
Seen best on CT or MRI.
Seen on plain images as expansion and asymmetry of affected IAC in advanced cases.

105

Describe a Cholesteatoma:

Benign cyst-like mass or tumor
Most common in middle ear or mastoid region secondary to trauma to this region
Destroys bone
Can lead to hearing loss

106

What is a Polyp:


Growth that arises from a mucous membrane and projects into cavity (sinus)
May cause chronic sinusitis

107

What is Otosclerosis?

Abnormal sponge-like bone grows in middle ear.
oto-=ear.
Sclerosis=hard.
Maybe heredity component.

108


Mesocephalic Skull:

Average head.
Width 75% to 80% of length.
Petrous pyramids project anteriorly and medially at an angle of 47 degrees from the midsagittal plane of the skull.

109

Brachycephalic skull:

Short from front to back
Broad from side to side
Shallow from vertex to base
Petrous pyramids form a wider angle with MSP
Average angle of 54°
Width is 80% or greater than the length

110

Dolichocephalic skull:

Long from front to back
Narrow from side to side
Deep from vertex to base
Long axes of petrous pyramids less frontal in position
Form an average angle of 40° with MSP
Width is less than 75% of the length.

111

CR angles and head rotations used for skull positioning are based on _______-shaped (_________) skull

average, Mesocephalic

112

Benefits of upright position for skull X-ray:

Allows patient to be quickly and easily positioned.
Permits use of horizontal beam to demonstrate air/fluid levels within cranial or sinus cavities.

113

Respiration suspended during exposure except in cases of

severe trauma.

114

Because cranial and facial radiography requires patient’s face to be in direct contact with radiographer’s hands and table/upright Bucky surface,

be sure to wash hands and the Bucky before and after every exam.

115

Exposure Factors for Cranium and Facial Bones:

-Medium kV (65 to 85 analog); (75 to 90 kV digital systems)
-Small focal spot less than 200 mA
-Short exposure time
-Minimum SID 40” (102 cm)

116

How to ensure proper Radiation Protection during cranium radiography:

-close collimation
-Minimize repeats
-Immobilization
-Center properly
-Shielding of radiosensitive organs recommended

117

Five Common Positioning Errors:

Rotation
Tilt
Excessive flexion
Excessive extension
Incorrect CR angle

118

To prevent superior or inferior pull on head resulting in angulation or tilt:

Place patient’s body so long axis of cervical vertebrae coincides with level of foramen magnum

119

Things to consider when xray'ing the cranium of a child:

Communication, Immobilization, Exposure factors

120

Pediatric communication for cranium xray:

-Clear explanation to gain trust of patient and guardian
-Distraction techniques

121

Immobilization considerations for pediatric skull xray:

-Immobilization devices support patient and reduce need for patient to be held
-Reduces radiation exposure
-Provide lead for persons holding patients; if female ensure no possibility of pregnancy

122

Exposure factors to consider during pediatric skull X-ray:

Vary with patient sizes and pathologies
High mA and short exposure times reduce motion

123

Things to consider during geriatric skull X-ray:

Communication and comfort, and exposure factors

124

Things to consider to ensure pt communication and comfort during geriatric skull X-ray:

-Sensory loss because of aging may result in need for additional assistance, time and patience for skull/facial bone/sinus radiography
-Radiolucent mattress
-Extra blankets
-Reassurance and attention
-Increased kyphosis
-Upright
-Horizontal beam lateral if necessary

125

Exposure factors to keep in mind during geriatric skull X-ray:

-Osteoporosis in geriatric patients may require 15% decrease if manual factors are used
-Tremors or unsteadiness: may require use of short exposure time (with high mA)

126

What is the most commonly performed neuroimaging procedure?

CT

127

CT and MRI provides sectional images of brain and bones of skull in ___, _____ or ____ planes

axial, sagittal or coronal

128

CT can differentiate between:

blood clots, white and gray matter, CSF, cerebral edema and neoplasms

129

Qualities unique to MRI skull exams:

-Increased sensitivity in detecting differences between normal and abnormal tissues in brain and soft tissues
-No ionizing radiation.
-Limited usefullness for evaluating bone; superior in evaluating soft tissue
-Useful for TMJ syndrome for diagnosing damage to articular disk of TM fossa

130

Ultrasound of brain of neonate (through fontanels) in ICU to for rapid evaluation and screening of premature infants for

intracranial hemorrhage

131

Why is US preferred over CT or MRI?

Highly portable
Less expensive
No sedation required
No ionizing radiation

132

What is Craniosynostosis?

premature cranial suture closure

133

Routine Skull Series:

AP axial (Towne method)
Lateral
PA axial 15º (Caldwell method) or PA axial (25º to 30º
PA 0º

134

Radionuclide bone scan is a sensitive diagnostic procedure for detection of ___________ that may not be demonstrated on radiographic images

osteomyelitis and occult fractures

135

Special skull series:

Submentovertex (SMV)
PA axial (Haas method)

136

Routine Optic Foramina and Orbits:

Parieto-orbital oblique (Rhese method)
Parietoacanthial (Waters method)

137

Special Optic Foramina and Orbits:

Modified parietoacanthial (modified Waters method)

138

Routine TMJ's

AP axial (modified Towne method

139

Special TMJ's

Axiolateral 15º oblique (modified Law method)
Axiolateral (Schuller method)

140

Towne's method is to view what bone?

Occipital

141

Clinical indications for Towne's method:

Skull fractures (medial and lateral displacement)
Neoplastic processes
Paget’s disease

142

Technical factors for Towne's method:

Minimum SID—40 in. (102 cm)
IR Size– 24x30 cm (10x12 in), lengthwise
Analog—70 to 80 kV range
Digital systems—80 to 85 kV range

143

Patient position for Towne's method:

All metal, plastic and other removable objects removed from patient’s head
Radiograph may be taken supine or erect

144

For Towne's method, chin is depressed until ___ is perpendicular to IR

OML

145

For Towne's, If patient cannot flex neck place ____ perpendicular
CR angle is increased to:

IOML, 7°

146

For Towne's, MSP aligned to __ and __________.
Ensure no _________.
Ensure ______ is in x-ray field

CR, midline of IR, rotation or tilt, vertex.

147

For Towne's, CR is angled:

30° to OML
or 37° to IOML

148

For Towne's, CR enters:

MSP 2 ½ inches above glabella to pass through foramen magnum
Center IR to projected CR

149

Anatomy demonstrated by Towne's method:

Occipital bone, petrous pyramids and foramen magnum demonstrated

Dorsum sellae and posterior clinoids visualized in the shadow of the foramen magnum

150

How do you know you have achieved the correct positioning for a Towne's method?

Symmetric petrous ridges:
Indicating no rotation.
Dorsum sellae and posterior clinoids projected in foramen magnum:
indicating correct CR angle and proper neck flexion/extension.

151

For Towne's method Underangulation of CR or insufficient flexion of neck projects dorsum sellae :

superior to the foramen magnum

152

For Towne's method Overangulation of CR or excessive flexion superimposes the ________ over the dorsum sellae within the foramen magnum and produces ________ of the dorsum sellae

anterior arch of C1 , foreshortening

153

For Towne's method, Shifting of anterior or posterior clinoid processes laterally within the foramen magnum indicates

tilt

154

For Towne's method, Density (brightness) and contrast sufficient to visualize _________ within foramen magnum

occipital bone and sellar structures

155

Clinical indications for left lateral:

Skull fractures, neoplastic processes and Paget’s disease.
Both R and L laterals are generally performed for a skull series.

156

Trauma routine for left lateral:

Horizontal beam lateral for trauma may demonstrate air-fluid levels in sphenoid sinus—a sign of a basal skull fracture if intracranial bleeding occurs

157

Technical factors for left lateral:

Minimum SID—40 in. (102 cm)
IR size—24x30 cm (10x12 in. crosswise)
Grid
Analog—70-80 kV range
Digital systems—80 to 85 kV range

158

Patient position for left lateral:

All metal, plastic or other removable objects removed from patient’s head

Patient radiographed in erect or recumbent semiprone position

159

Part position for left lateral:

Head placed in true lateral position with side of interest closest to IR.
Patient’s body in semiprone position with MSP parallel to IR ensuring no rotation or tilt

160

For left lateral, Align ___ perpendicular to IR, ensuring no tilt of head.
Adjust neck flexion to align ____ perpendicular to front edge of IR.
___ parallel to front edge of IR.

IPL, IOML, GAL

161

For left lateral, Large-chested patients may require radiolucent support under head to prevent

tilt

162

For left lateral, Thin patient may require support under

upper thorax

163

For left lateral, central ray is perpendicular to IR
Enters __________,
Or halfway between ___________ for other types of skull morphologies.
IR centered to __.

2” superior to EAM, glabella and inion, CR

164

Anatomy demonstrated by left lateral:

Entire cranium visualized
Superimposed parietal bones
Sella turcica including:
Anterior and posterior clinoid processes
Dorsum sellae
Sella turcica and clivus demonstrated in profile

165

For left lateral, rotation evident by:

anterior and posterior separation of symmetric vertical bilateral structures:
EAMs
Mandibular rami
Greater wings of sphenoid

166

For left lateral, tilt is evident by:

superior and inferior separation of symmetric horizontal structures:
Orbital roofs (plates)
Greater wings of sphenoid

167

Clinical indications for PA Caldwell (PA Axial projection)

Skull fractures (medial and lateral displacement)
Neoplastic processes
Paget’s disease

168

Technical factors for PA Caldwell

Minimum SID—40 in. (102 cm)
IR size--24x30 cm (10x12”) lengthwise
Grid
Analog—70-80 kV range
Digital systems—80-85 kV range

169

Patient position for PA Caldwell:

All metallic or plastic objects removed from patient’s head and neck
May perform erect or prone recumbent

170

Part position for PA Caldwell:

Nose and forehead resting against IR
Neck flexion adjusted so OML is perpendicular to IR
MSP aligned to be perpendicular to midline of grid/table/IR to prevent rotation or tilt
Center IR to CR

171

Central ray for PA Caldwell:

CR angled 15° caudad and centered to exit at nasion (Caldwell method)
OR
CR angled 25° to 30° caudad exits at nasion

172

PA Caldwell: 25º to 30º caudad angle: allows for visualization of:

the superior orbital fissures (black arrows) and foramen rotundum (white arrows), and entire inferior orbital rims

173

15º caudad angle (Caldwell): projects petrous pyramids into

lower third of the orbits

174

For PA Caldwell: Alternate AP axial projection:

15° cephalad angle with OML perpendicular to IR.
Performed when patient is unable to be positioned for PA projection.
Orbits magnified.

175

Anatomy Demonstrated:
Caldwell method (15° caudad angle)

Greater and lesser sphenoid wings
Frontal bone
Superior orbital fissures
Frontal and anterior ethmoid sinuses
Supraorbital margins
Crista galli

176

Anatomy demonstrated: PA with 25° to 30° angle:

Structures mentioned for Caldwell method and
Foramen rotundum (white arrows)
Entire superior orbital fissures (black arrows)
Inferior orbital rims

177

How to show evidence of no rotation on PA Caldwell:

Equal distance from midlateral orbital margins to lateral cortex of cranium on each side.
Superior orbital fissures symmetric within orbits with correct extension of neck (OML alignment).
NO tilt with MSP perpendicular to IR.

178

How to show evidence of no rotation on PA Caldwell
with 15° caudal angle:

Petrous pyramids projected in lower third of orbits.
Superior orbital margin visualized without superimposition.

179

How to show evidence of no rotation on PA Caldwell with 25° to 30° angle:

Petrous pyramids are projected at or just below inferior orbital rim to allow visualization of entire orbital margin.

180

Correct exposure for PA Caldwell shows:

Density (brightness) and contrast sufficient to visualize frontal bone and sellar structures without overexposure to perimeter regions of skull

181

Clinical Indications for PA Caldwell with no angle:

Skull fractures (medial and lateral displacement)
Neoplastic processes
Paget’s disease
*when frontal bone is of primary interest.*

182

Technical factors for PA Caldwell with no angle:

Minimum SID—40” (102 cm)
IR Size--24x30 cm (10x12”) lengthwise
Grid
Analog—70 to 80 kV range
Digital systems—80 to 85 kV range

183

Part position for PA Caldwell with no angle:

Nose and forehead rested against IR
Adjust neck flexion until OML is perpendicular to IR
MSP perpendicular to IR (EAM same distance from table/IR)
Center IR to CR

184

Central Ray for PA Caldwell with no angle:

CR is perpendicular to IR (parallel to OML)
CR exits at glabella
(Merrill’s – nasion)
Minimum 40” (100 cm) SID

185

Anatomy demonstrated on PA Caldwell with no angle:

Frontal bone
Crista galli
Internal auditory canals
Frontal and anterior ethmoid sinuses
Petrous ridges
Greater and lesser sphenoid wings
Dorsum sellae

186

How to show evidence of no rotation on PA Caldwell with no rotation:

Equal distance bilaterally from oblique orbital line to lateral cortex of skull.
Petrous ridges fill orbits and level of supraorbital margin
Posterior and anterior clinioids visualized superior to ethmoid sinuses

187

Trauma AP with no angle:

CR parallel to OML
CR to glabella

188

Before positioning the patient for an SMV projection, what needs to be ruled out?

Cervical spine fracture or subluxation on trauma patient

189

Clinical indications for SMV projection:

Advanced bony pathology of inner temporal bone structures (skull base)
Possible basal skull fractures

190

Technical factors for SMV projection:

Minimum SID—40” (102 cm)
IR size--24x30 cm (10x12”) lengthwise
Grid
Analog—75 to 85 kV range
Digital systems—80 to 90 kV range

191

Pt position for SMV projection:

Erect position may be easier for patient—upright table or upright imaging device
Wheelchair can be used; offers support for back and provides greater stability for maintaining position

192

Part position for SMV projection:

Hyperextend neck until IOML is parallel to IR
If patient is unable to extend neck angle CR so it is perpendicular to IOML
Rest patient’s head on vertex
MSP perpendicular to IR

193

Central ray for SMV projection:

Perpendicular to IOML
Center 1 ½ inches inferior to mandibular symphysis (or midway between gonions)
Center IR to CR

194

Anatomy demonstrated for SMV projection:

Foramen ovale and spinosum
Mandible
Sphenoid and posterior ethmoid sinuses
Mastoid processes
Petrous ridges
Hard palate
Foramen magnum
Occipital bone

195

For SMV projection, Correct extension of neck and relationship between IOML and CR as indicated by:

Manibular condyles projected anterior to petrous pyramids
Frontal bone and mandibular symphysis superimposed

196

To ensure no rotation for SMV projection:

MSP parallel to edge of IR

197

To ensure no tilt for SMV projection:

Equal distance between mandibular ramus and lateral cranial cortex.

198

Correct exposure for SMV projection evidenced by:

Density (brightness) and contrast sufficient to visualize clearly outline of ethmoid and sphenoid sinuses and cranial foramen

199

What is the Haas method an alternative for, and when is it done?

Haas devised this projection for obtaining an image of the sellar structures projected within the foramen magnum on hypersthenic, obese, or other patients who cannot be adjusted correctly for the AP axial (Towne) projection

200

What are to two largest differences between the Towne method and Haas method?

Occipital bone magnified with this method
Lower dose to facial structures and thyroid

201

Clinical indications for Haas method:

Skull fractures (medial and lateral displacement)
Neoplastic processes
Paget’s disease

202

Technical factors for Haas method:

Minimum SID—40” (102 cm)
IR size—24x30 cm (10x12”), lengthwise
Grid
Analog—70 to 80 kV range
Digital systems—80 to 85 kV range

203

Part position for Haas method:

Patient’s nose and forehead rests against imaging device surface
Flex neck until OML is perpendicular to IR
MSP aligned to CR and imaging device surface
MSP perpendicular to IR
Ensure no rotation or tilt

204

Central ray for Haas method:

Angle CR 25° cephalad to OML
Center CR to MSP to pass through level of EAMs and exit 1 ½ inches superior to nasion.
Center IR to projected CR

205

Anatomy demonstrated by Haas method:

Occipital bone
Petrous pyramids
Foramen magnum
Dorsum sellae and posterior clinoids visualized in the shadow of the foramen magnum

206

No rotation on Haas method evidenced by:

Symmetric petrous ridges

207

Correct CR angle and proper neck flexion /extension for Haas method evidenced by:

Dorsum sellae and posterior clinoids visualized in foramen magnum

208

No tilt on Haas method evidenced by:

Correct placement of posterior (book says anterior) clinoids within middle of foramen magnum

209

Correct exposure for Haas method evidenced by:

Density (brightness) and contrast sufficient to visualize occipital b one and sellar structures within foramen magnum. Sharp bony margins indicate no motion

210

The width of the dolichocephalic skull is less than ____of the length.
65%
75%
80%
90%

75%

211

The angle between the midsagittal plane and the long axis of the petrous portion of the temporal bone in the brachycephalic skull is

45°
40°
38°
47° or greater

47 degrees or greater.

212

The midline point at the junction of the upper lip and the nasal septum is called

Acanthion
Nasion
Glabella
Mentum

Acanthion

213

The tragus is located on the

Lateral border of the orbit
Point above the superciliary arch
External ear
Bridge of the nose

External ear.

214

There is a ___ difference between the orbitomeatal and infraorbitomeatal lines.

2° to 3°

7° to 8°
10° to 12°

7-8 degree

215

Metastatic osteoblastic lesions of the cranium are proliferative bony lesions of increased density.

True
False

True

216

How much CR angle is required for the AP axial projection of the skull if the IOML is perpendicular to the IR?

25°
30°
37°
40°

37 degrees

217

Which positioning error is present if the orbital plates are not superimposed on a lateral skull radiograph?

Incorrect CR angle
Excessive flexion
Rotation
Tilt

Tilt

218

Which variation of the PA (axial) projection of the skull has been performed if the petrous ridges are at the level of the supraorbital margin?

PA 15°
PA 25°
PA 30°
PA 0°

PA no angle.

219

Which positioning error is present if the mandibular condyles are seen within the petrous portion of the temporal bone on an SMV projection?

Excessive extension
Insufficent extension
Rotation
Incorrect CR angle

Insufficient extension

220

What type of CR angle is required for a PA axial (Haas method) projection of the skull?

25° cephalad
30°caudad
37° caudad
15° caudad

25 degrees cephalad