Chapter 11 Cranium
Which aspect of the temporal bone is considered the densest?
Petrous portion
Which imaging modality is best to differentiate between an epidural and a subdural hemorrhage? A. CT B. MRI C. Nuclear medicine D. PET
A. CT
List the four most commonly performed routine projections for paranasal sinuses. A. ___________ B. ___________ C. ___________ D. ___________
A. Lateral B. PA Caldwell C. Parietoacanthial (Waters method) D. SMV
Which specific positioning error is present if the mandibular rami are not superimposed on a lateral skull radiograph? A. Tilt B. Rotation C. Overflexion of head and neck D. Incorrect central ray angle
B. Rotation
Which of the following projections best demonstrates the foramen rotundum? A. SMV B. 25 to 30-degree AP axial C. 25 to 30-degree PA axial D. Lateral
C. 25 to 30-degree PA axial
A small prominence located on the squamous portion of the occipital bone is called the
External occipital protuberance, or inion
Which paranasal sinuses are best demonstrated with a PA (Caldwell) projection?
Frontal and anterior ethmoid
Which two cranial bones articulate with the maxilla?
Frontal and ethmoid
If the patient cannot flex the head adequately for the AP axial (Towne method) projection, the technologist could place the __________________________ perpendicular to the image receptor and angle the central ray __________________________ degrees caudad.
IOML; 37
What device provides inherent collimation during an orthopantomographic procedure?
Narrow, vertical slit diaphragm
Which cranial bone is best demonstrated with an AP axial (Towne method) projection of the skull?
Occipital
Which sinus is projected through the open mouth with a PA axial transoral projection?
Sphenoid sinus
name all the asterions of the skull
bregam, lamdoidal, pterion, asterion
What is the name of the notch that separates the orbital plates from each other? __________________________
ethmoidal notch
Cranial sutures are classified as being _____ joints.
fibrous or synarthrodial
Which radiographic projection best demonstrates the sella turcica and dorsum sellae?
lateral projection
Which cranial bone contains the foramen magnum?
occipital bone
Which cranial bones form the upper lateral walls of the calvarium?
right and left parietals
A structure found in the middle of the sphenoid bone that surrounds the pituitary gland is the
sella turcica
Which term describes the superior rim of the orbit? (Include the abbreviation also.) __________________________
supraorbital margin (SOM)
Small, irregular bones that sometimes develop in adult skull sutures are called __________________________ or __________________________ bones and are most frequently found in the __________________________ suture.
sutural or wormian, lambdoidal
The long, narrow-shaped skull has an angle of approximately __________________________ degrees between the midsagittal plane and the long axis of the petrous bone.
±40
From anterior to posterior, the cone-shaped orbits project upward at an angle of __________________________ degrees and toward the midsagittal plane at an angle of __________________________ degrees.
30 degrees, 37 degrees
What is the average kV range for analog skull radiography? kV range for digital imaging?
75 to 85 kV (analog) and 80 to 90 kV (digital systems)
A lateral skull radiograph demonstrates one mandibular ramus about 0.5 cm more anterior than the other. Which positioning error occurred?
Skull rotation
Situation: A radiograph of a PA (Caldwell) projection for sinuses shows that the petrous ridges are projected into the lower half of the orbits and are obscuring the ethmoid sinuses. The technologist used a horizontal x-ray beam for the projection. The skull was positioned to place the OML at a 15-degree angle from the horizontal plane. What positioning modification is needed to correct this problem during the repeat exposure?
The head and neck need to be extended more to project the petrous ridges below the ethmoid sinuses.
True/False: Both oblique inferosuperior (tangential) projections for the zygomatic arch are generally taken for comparison.
True
True/False: CT is ideal for facial bone studies because it allows for the visualization of bony structures as well as related soft tissues of the facial bones.
True
True/False: For a true PA projection of the mandibular body (if this is the area of interest), the AML should be perpendicular to the image receptor.
True
True/False: Lateral projections for nasal bones generally are taken bilaterally for comparison.
True
True/False: Magnetic resonance imaging is the preferred modality to study soft tissue changes and masses within the sinuses.
True
True/False: Most CT studies of the sinuses do not require the use of contrast media.
True
True/False: The common basic PA axial projection for facial bones requires a 15-degree caudad angle of the central ray, which projects the dense petrous ridges into the lower one-third of the orbits.
True
True/False: The mandibular condyles move anteriorly as the mouth is opened.
True
True/False: The modified Law method provides a bilateral and functional study of the TMJ.
True
True/False: Ultrasound exams of the maxillary sinuses to rule out sinusitis are possible.
True
The single facial bone and the one pair of facial bones not visible from the exterior and not demonstrated in Figs. 11.18 and 11.19 are the __________________________ and the __________________________, respectively. (These are demonstrated in special-view drawings in the following questions.)Identify the labeled structures (and the facial bones of which they are a part) on this inferior surface view of the maxillae (Fig. 11.20).
Vomer and the palatine bones
What is the proper method name for the parietoacanthial projection of the facial bones?
Waters method
Situation: A patient comes to the radiology department with a possible tumor of the pituitary gland. Which radiographic projection of the cranium best demonstrates any bony involvement of the sella turcica?
Collimated, lateral projection of the sella turcica
The posterior aspect of the sella turcica is called the
Dorsum Salle
True/False: Facial bone studies should always be performed recumbent whenever possible.
False (Best to perform erect)
True/False: Nuclear medicine is not helpful in diagnosing occult facial bone fractures.
False (It is used for this.)
True/False: The right and left nasal bones form the largest part of the nose.
False (Most of the nose is composed of cartilage.)
True/False: MRI is an excellent imaging modality for the detection of small metal foreign bodies in the eye.
False (Strong magnets in MRI prohibit this.)
True/False: Two older terms for the orbitomeatal line (OML) are Reid's base line and the anthropologic base line.
False (These are other terms for the infraorbitomeatal line.)
True/False: The CR should be angled 20 to 25 degrees caudad for the PA axial projection of the mandible.
False (cephalad)
True/False: The mastoid portion of the temporal bone is the densest of the three aspects of the temporal bone.
False (petrous portion)
True/False: The oblique inferosuperior (tangential) tangential projection for a unilateral zygomatic arch requires that the skull be rotated and tilted 15 degrees away from the affected side.
False (toward the affected side)
Which of the processes mentioned in question number 3 is considered most superior?
Frontal process
Where is the CR centered for an AP axial projection of the mandible?
Glabella
For the superoinferior projection of the nasal bones, the image receptor is placed perpendicular to the __________________________ line. (Include the full term and abbreviation.)
Glabelloalveolar (GAL)
Identify the three foramina found within the orbits as labeled in Fig. 11.24. H. ___________ I. ___________ J. ___________ Small section of bone: K. ___________
H. Optic foramen I. Superior orbital fissure J. Inferior orbital fissure K. Sphenoid strut
Which opening in the temporal bone serves as a passageway for nerves of hearing and equilibrium?
Internal acoustic meatus
Which specific aspect of the ethmoid bone contains the ethmoid sinuses?
Lateral masses or labyrinths
Aligning the __________________________ plane perpendicular to the IR prevents rotation of either a PA or an AP axial mandible.
Midsagittal
Situation: A patient with a possible blowout fracture of the right orbit enters the emergency room. In addition to the basic facial bone routine, what single projection would best demonstrate this type of injury?
Modified parietoacanthial (modified Waters method) projection
Name all the fontanels in the fetal skull
Posterior Fontanel Anterior Fontanel Mastoid Sphenoid
Which aspect of the frontal bone forms the superior aspect of the orbit?
orbital or horizontal portion
Which projection of the cranium produces an image of the frontal bone with little or no distortion?
0 degrees posteroanterior (PA)
Where is the CR centered for an AP axial projection for the zygomatic arches?
1 inch (2.5 cm) superior to glabella to pass through midarches (at level of gonion)
How long is the average external acoustic meatus (EAM)?
1 inch (or 2.5 cm)
Match each of the following sinus projections with the anatomy best seen. (Use each choice only once.) ______ 1. Lateral ______ 2. Parietoacanthial ______ 3. PA (axial) Caldwell ______ 4. PA transoral ______ 5. SMV for sinuses A. Sphenoid sinus in oral cavity B. Inferosuperior view of sphenoid and ethmoid sinus C. All four paranasal sinuses demonstrated D. Best view of maxillary sinuses E. Best view of frontal and ethmoid sinuses
1. C 2. D 3. E 4. A 5. B
Match each of the following structures to the facial bone projection that best demonstrates the structure(s). (Use each choice only once.) ______ 1. Floor of orbits (blowout fractures) ______ 2. Optic foramen ______ 3. View of single zygomatic arch ______ 4. Profile image of nasal bones and nasal septum ______ 5. Bilateral zygomatic arches ______ 6. Inferior orbital rim, maxillae, nasal septum, nasal spine, zygomatic bone, and arches A. Lateral (nasal bones) B. Parietoacanthial projection C. Parieto-orbital oblique projection D. Submentovertical (SMV) projection E. Modified Waters method F. Oblique inferosuperior projection
1. E 2. C 3. F 4. A 5. D 6. B
Match each of the following cranial landmarks and positioning lines with the correct definition. (Use each choice only once.) ______ 1. Lateral junction of the eyelid ______ 2. Posterior angle of the jaw ______ 3. A line between the infraorbital margin and the EAM ______ 4. Corresponds to the highest "nuchal" line of the occipital bone ______ 5. A line between the glabella and alveolar process of the maxilla ______ 6. A line between the mental point and the EAM ______ 7. Located at the junction of the two nasal bones and the frontal bone ______ 8. The small cartilaginous flap covering the ear opening ______ 9. Corresponds to the highest level of the facial bone mass ______ 10. A line between the midlateral orbital margin and the EAM ______ 11. The center point of the EAM ______ 12. A positioning line that is primarily used for the modified Waters projection ______ 13. A line used in positioning to ensure that the skull is in a true lateral position ______ 14. Corresponds to the level of the petrous ridge ______ 15. A smooth, slightly depressed area between the eyebrows A. TEA B. Supraorbital groove C. Interpupillary line D. Nasion E. Gonion F. Tragus G. Outer canthus H. Glabelloalveolar line I. OML J. Infraorbitomeatal line (IOML) K. Mentomeatal line L. Lips-meatal line M. Glabella N. Inion O. Auricular point
1. G 2. E 3. J 4. N 5. H 6. K 7. D 8. F 9. B 10. I 11. O 12. L 13. C 14. A 15. M
To avoid angling the CR for the erect PA (axial) Caldwell sinus projection, the head should be adjusted so that the OML is __________________________ degrees from horizontal.
15 degrees
Where is the central ray centered for a lateral projection of the skull?
2 inches (5 cm) above the EAM
What central ray angle should be used for the PA axial (Haas method) projection for the cranium?
25 degrees cephalad
The axiolateral (Schuller method) projection for the TMJ requires a CR angle of __________________________ degrees (caudad or cephalad).
25 to 30 degrees; caudad
If the area of interest is the temporomandibular fossae, angle the CR __________________________ to the OML for the AP axial (modified Towne) projection to reduce superimposition of the TM fossae and mastoid portions of the temporal bone.
40 degrees caudad
The frontal sinuses rarely become aerated before the age of
6 years
There is a __________________________-degree difference between the orbitomeatal and infraorbitomeatal lines, and __________________________ degrees between the orbitomeatal and glabellomeatal lines.
7- to 8-degree; 7 to 8 degrees (same degrees of difference)
What analog kV range should be used for sinus radiography? __________________________ Digital kV range? __________________________
70 to 85 kV (analog); 80 +/− 5 kV (digital systems)
Where does the CR exit for a PA axial (Haas method) projection of the skull? A. 1 1/2 inches (4 cm) superior to the nasion B. 3/4 inch (2 cm) anterior to the EAM C. 2 1/2 inches (6.5 cm) above the glabella D. Level of nasion
A. 1 1/2 inches (4 cm) superior to the nasion
Match each of the following clinical indications to the correct definition or statement. (Use each choice only once.) A. Fracture that may produce an air-fluid level in the sphenoid sinus B. Destructive lesion with irregular margins C. Also called a "ping-pong" fracture D. Proliferative bony lesion of increased density E. A tumor that may produce erosion of the sella turcica F. Also known as osteitis deformans G. A bone tumor that originates in the bone marrow 1. Osteoblastic neoplasm 2. Pituitary adenoma 3. Basal skull fracture 4. Paget's disease 5. Osteolytic neoplasm 6. Depressed skull fracture 7. Multiple myeloma
A. 3 B. 5 C. 6 D. 1 E. 2 F. 4 G. 7
Match each of the following mandibular terms to the correct definition or description. (Use each choice only once.) A. Gonion B. Mandibular notch C. Body D. Condyloid process E. Coronoid process F. Ramus G. Mentum H. Symphysis menti 1. Vertical portion of mandible 2. Chin 3. Mandibular angle 4. Point of union between both halves of the mandible 5. Bony process located anterior to mandibular notch 6. Horizontal portion of mandible 7. Posterior process of the upper ramus 8. U-shaped notch
A. 3 B. 8 C. 6 D. 7 E. 5 F. 1 G. 2 H. 4
How much skull rotation (from the lateral skull position) toward the image receptor is required with an axiolateral oblique projection for demonstrating each of the following? A. Body of the mandible: ________________________ B. Mentum region: ________________________ C. Ramus region: ________________________ D. General survey of the mandible: ________________________ E. What is the maximum CR angle needed for all of these projections? ________________________
A. 30 degrees B. 45 degrees C. 0 degrees, true lateral D. 10 to 15 degrees E. 25 degrees cephalad
A. What CR angle is required for the AP axial projection of the mandible if the OML is placed perpendicular to the image receptor? __________________________ B. If the infraorbitomeatal line (IOML) is perpendicular to IR, what CR angle is needed?
A. 35 degrees caudad B. 42 degrees caudad
Fill in the total number of bones. A. Cranium ___________ B. Facial bones ___________
A. 8 B. 14
Which of the following clinical indications may require an increase in manual exposure factors? A. Advanced Paget's disease B. Metastatic neoplasm C. Multiple myeloma D. Basal skull fracture
A. Advanced Paget's disease
The three aspects of the face that should be in contact with the head unit or tabletop when beginning positioning for the parieto-orbital oblique projection are the (A) ________________________, ________________________, and ________________________. The final angle between the midsagittal plane and the IR should be (B) ________________________, with the (C) ________________________ line perpendicular to the IR. This places the optic foramen in the (D) ________________________ quadrant of the orbit.
A. Cheek, nose, chin B. 53 degrees C. Acanthiomeatal D. Lower outer
Which of the following imaging modalities is the most common neuroimaging procedure performed for the cranium? A. Computed tomography (CT) B. Ultrasound C. Magnetic resonance imaging (MRI) D. Nuclear medicine
A. Computed tomography (CT)
Identify the parts of the mandible and skull as labeled in Figs. 11.22 and 11.23. A. ___________ B. ___________ C. ___________ D. ___________ E. ___________ F. ___________ G. ___________ H. ___________ I. ___________ J. ___________ K. (Cranial bone) ___________ L. (Joint) ___________ M. (Key landmark) ___________ N. (Landmark) ___________
A. Condyle B. Neck C. Ramus D. Gonion or mandibular angle E. Body F. Mental foramen G. Mentum or mental protuberance H. Alveolar process I. Coronoid process J. Mandibular notch K. Temporal bone L. Temporomandibular joint (TMJ) M. External auditory meatus (EAM) N. Mastoid process
Identify the labeled parts on the three views of the ethmoid bone (Figs. 11.5 and 11.6).
A. Crista galli B. Cribriform plate C. Perpendicular plate D. Lateral labyrinth (mass) E. Middle nasal conchae (turbinate)
Identify all eight cranial bones on the two superior-view drawings (Figs. 11.3 and 11.4)
A. Frontal B. Ethmoid C. Sphenoid D. Left temporal E. Left parietal F. Occipital G. Right parietal H. Right temporal
List the four cranial bones that form the calvaria (skull cap).
A. Frontal B. Right parietal C. Left parietal D. Occipital
Identify the cranial bones labeled in Figs. 11.1 and 11.2. (Note: All eight cranial bones, including each paired bone, are visible in at least one of the following drawings.)
A. Frontal B. Right parietal C. Right temporal D. Sphenoid E. Ethmoid F. Left temporal G. Left parietal H. Occipital
List the four processes of the maxilla.
A. Frontal process B. Zygomatic process C. Alveolar process D. Palatine process
What are two differences between the lateral projection of the cranium and the lateral projection for the facial bones? A. ___________ B. ___________
A. IR is placed in portrait orientation for facial bones but landscape for the cranium. B. CR is centered to the zygoma for facial bones and 2 inches (5 cm) above the EAM for the cranium.
16. Identify the seven bones that form the orbit and indicate whether they are cranial or facial bones (Fig. 11.24). (See pp. 398-399.) BoneCranial or Facial? A. ___________ (___________) B. ___________ (___________) C. ___________ (___________) D. ___________ (___________) E. ___________ (___________) F. ___________ (___________) G. ___________ (___________)
A. Lacrimal (facial) B. Ethmoid (cranial) C. Frontal (cranial) D. Sphenoid (cranial) E. Palatine (facial) F. Zygomatic (facial) G. Maxilla (facial)
Bilateral horizontal fractures of the maxillae describe a __________________________ fracture. A. Le Fort B. Blowout C. Tripod D. Contrecoup
A. Le Fort
A. Which group of paranasal sinuses is best demonstrated with a parietoacanthial (Waters) projection? ___________________________________________________ B. The OML forms a __________________________-degree angle with the image receptor with this projection.
A. Maxillary B. 37-degree
1. List the three classifications of the skull; then match them with the correct shape description listed on the right.
A. Mesocephalic - Width between 75% and 80% of length B. Brachycephalic - Width ≥80% of length C. Dolichocephalic - Width <75% of length
Which of the following bones is not a facial bone? A. Middle nasal conchae B. Vomer C. Lacrimal bone D. Mandible
A. Middle nasal conchae
The axiolateral oblique projection of the TMJ is commonly referred to as the (A) __________________________ method, which requires a (B) __________________________-degree head rotation from lateral and a (C) __________________________-degree caudad CR angle.
A. Modified Law B. 15-degree C. 15-degree
Identify the labeled facial bones visible in Figs. 11.18 Paired Bones A. ___________ B. ___________ C. ___________ D. ___________ E. ___________ Single Bone F. ___________
A. Nasal bones B. Lacrimal bones C. Zygomatic bones D. Maxillary bones E. Inferior nasal conchae F. Mandible
Identify the sinuses, structures, or bones labeled in Fig. 11.25. A. ___________ B. ___________ C. ___________ D. ___________ E. ___________ F. ___________ G. ___________ H. ___________ I. ___________ J. ___________ K. ___________ L. ___________ M. ___________
A. Nasal cavity (fossae) B. Maxillary sinuses C. Right temporal bone (squamous portion) D. Frontal sinuses E. Ethmoid sinuses F. Sphenoid sinuses G. Maxillary sinuses H. Ethmoid sinuses I. Frontal sinuses J. Squamous portion of left temporal bone K. Mastoid portion of left temporal bone L. Sphenoid sinus M. Roots of upper teeth (alveolar process)
When using a 30-degree caudad angle for the AP axial (Towne method) projection of the skull, which positioning line should be perpendicular to the image receptor? A. OML B. IOML C. GAL D. AML
A. OML
To demonstrate any possible air or fluid levels within the sinuses, it is important to: A. ___________ B. ___________
A. Perform positions erect when possible B. Use horizontal x-ray beam
List the three structures that form the nasal septum as shown in Fig. 11.21.
A. Perpendicular plate of ethmoid B. Vomer C. Septal cartilage
Structure / Bone(s) A. ___________ (___________) B. ___________ (___________) C. ___________ (___________) D. ___________ (___________)
A. Pterygoid hamulus, sphenoid B. Right palatine process, right maxilla C. Left palatine process, left maxilla D. Horizontal portions, right and left palatine bones
Give two reasons why projections of the facial bones are performed PA rather than AP when possible. A. ___________ B. ___________
A. Reduces OID of facial bones B. Reduces exposure to anterior facial bones and neck structures such as thyroid glands
List the proper method name and the common descriptive name for the parieto-orbital oblique projection for the optic foramen. A. ___________ B. ___________
A. Rhese method B. Three-point landing
List the four cranial bones that form the floor of the cranium
A. Right temporal B. Left temporal C. Sphenoid D. Ethmoid
Of the five causes listed in the previous question, which two are the most common?
A. Rotation B. Tilt
List the five most common errors made during skull radiography.
A. Rotation B. Tilt C. Excessive neck flexion D. Excessive neck extension E. Incorrect central ray angulation
Identify the following paranasal sinuses labeled in Figs. 11.26. Fig. 11.26 A. ___________ B. ___________ C. ___________ D. ___________
A. Sphenoid sinus B. Maxillary sinuses C. Ethmoid sinuses D. Frontal sinus
List the three aspects of the temporal bones
A. Squamous B. Mastoid C. Petrous
List the three aspects of the temporal bones.
A. Squamous B. Mastoid C. Petrous
Which of the facial bone openings is formed by a cleft between the greater and lesser wings of the sphenoid bone? A. Superior orbital fissure B. Optic foramen C. Inferior orbital fissure D. Optic canal
A. Superior orbital fissure
Where does the CR exit for a parietoacanthial (Waters) projection of the facial bones?
Acanthion
Which soft tissue landmark is found at the base of the anterior nasal spine?
Acanthion
Where should the CR exit for a PA axial projection of the mandible?
Acanthion (at lips for PA projection)
Situation: As part of a study of the zygomatic arches, the technologist attempts to perform the SMV position. Because of the size of the patient's shoulders, he is unable to flex his neck adequately to place the IOML parallel to the image receptor. What other options does the technologist have to produce an acceptable SMV projection?
Angle CR to place it perpendicular to the IOML. Angle the image receptor to maintain a perpendicular relationship between the CR and the image receptor. This will prevent distortion of the anatomy.
What is the older term for the maxillary sinuses?
Antrum of Highmore
Which structure makes up the cartilaginous external ear?
Auricle or pinna
Which projection of the mandible projects the opposite half of the mandible away from the side of interest?
Axiolateral oblique
What CR angle must be used to project the petrous ridges just below the orbital floor with the PA axial (Caldwell method) projection? A. None. CR is perpendicular. B. 30 degrees C. 20 degrees D. 45 degrees
B. 30 degrees
Which skull positioning line is placed parallel to the plane of the IR for the SMV projection? A. OML B. IOML C. AML D. GML
B. IOML
Which of the following bones does not articulate with the zygomatic bone?
B. Mandible
What is another term for the second cranial nerve?
B. Optic nerve
The drainage pathway for the paranasal sinuses is called the:\ A. Uncinate process B. Ostiomeatal complex C. Paranasal meatus D. Lateral masses
B. Ostiomeatal complex
Which position is most often used when performing a CT study of the sinuses?
B. Prone
Which projection/method of the TMJ requires that the skull be kept in a true lateral position? A. Modified Law B. Schuller C. Axiolateral oblique projection D. Modified Towne
B. Schuller
Which of the following imaging modalities is commonly performed on neonates with a possible intracranial hemorrhage? A. CT B. Ultrasound C. MRI D. Nuclear medicine
B. Ultrasound
Specifically, where are the frontal sinuses located?
Between the inner and outer tables of the skull, posterior to the glabella
What is the name of the fracture that results from a direct blow to the orbit leading to a disruption of the inferior orbital margin?
Blow-out fracture
A properly positioned AP axial (Towne method) projection should place the dorsum sellae into the middle aspect of the: A. Orbits B. Clivus C. Foramen magnum D. Anterior arch of C1
C. Foramen magnum
Which of the following projections best demonstrates the clivus in profile? A. AP axial B. 15-degree PA C. Lateral D. SMV
C. Lateral
Where is the CR centered for a lateral position for the facial bones? A. Outer canthus B. Acanthion C. Zygoma D. Nasion
C. Zygoma
An AP axial (Towne method) radiograph for the cranium demonstrates the dorsum sellae projected above, or superior to, the foramen magnum. The foramen magnum is distorted. Which positioning error(s) occurred?
Central ray angled <37 degrees to the IOML, or <30 degrees to the OML (would be caused by 30-degree angle to IOML). This error can be addressed with more flexion of the neck as well.
The purpose of the __________________________, or __________________________, is to divide the nasal cavity into compartments and to circulate air coming into the nasal cavities. (Include both terms for these bones.)
Conchae, turbinates
Which aspect of the mandible is best visualized with an AP axial projection?
Condyloid process
name all the sutures of the skull
Coronal, sagittal, lambdoid, squamous, sphenosquamous, sphenofrontal, sphenoparietal.
The small horizontal plate of the ethmoid, seen on Fig. 11.6, is called the
Cribiform plate
What type of image receptor must be used with analog orthopantomography?
Curved, nongrid cassette
Which of the following projections best demonstrates the sella turcica in profile? A. AP axial B. SMV C. 15-degree PA axial D. Lateral
D. Lateral
Which of the following imaging modalities is most commonly performed to evaluate patients for Alzheimer disease? A. CT B. Ultrasound C. MRI D. Nuclear medicine
D. Nuclear medicine
A lack of symmetry of the petrous ridges indicates which of the following problems with a radiograph of an AP axial projection? A. Tilt B. Central ray angle C. Flexion or extension D. Rotation
D. Rotation
What is the major disadvantage of performing a straight PA projection for facial bones, with no CR angulation or neck extension, as compared with other PA facial bone projections?
Dense petrous pyramids superimpose the orbits, obscuring facial bone structures.
What evidence on an AP axial (Towne method) radiograph indicates whether the correct central ray angle and correct head flexion were used?
Dorsum sellae and posterior clinoids should be projected into the foramen magnum.
Identify the following paranasal sinuses labeled in Figs. 11.27. Fig. 11.27 E. ___________ F. ___________ G. ___________ H. ___________
E. Frontal sinuses F. Sphenoid sinus G. Ethmoid sinuses H. Maxillary sinuses
Situation: A patient with a clinical history of acoustic neuroma comes to the radiology department. Which imaging modality or modalities can be performed for this type of pathology?
Either MRI or CT can be performed.
A radiograph of a 15-degree PA axial (Caldwell) projection of the cranium demonstrates that the petrous ridges are projected at the inferior orbital margin. Which positioning error(s) led to this radiographic outcome?
Excessive extension or excessive caudad central ray angle—projects the petrous ridges lower than expected (should be in the lower third of the orbit)
Situation: A radiograph of a superoinferior projection of the nasal bones shows that the glabella are superimposed over the nasal bones. What positioning error led to this radiographic outcome, and how can it be corrected during the repeat exposure?
Excessive flexion of the head and neck or incorrect CR angle will project the glabella into the nasal bones. The CR must be parallel to the glabelloalveolar line.
Which specific positioning error is present if the petrous ridges are projected higher in the orbits than expected for a 15-degree PA axial projection?
Excessive flexion or insufficient central ray angle
What must be done to prevent the ramus of the mandible from being superimposed over the cervical spine with an axiolateral oblique projection of the mandible?
Extend the chin
True/False: An increase in kV of 25% to 30% (using manual techniques) is often required for the geriatric patient with advanced osteoporosis.
False
True/False: Secondary osteomyelitis is often caused by tumor invasion.
False
Situation: A patient with a possible basal skull fracture enters the emergency room. No CT scanner is available. Which specific position may provide radiographic evidence of this fracture?
Horizontal beam (dorsal decubitus) lateral position—will demonstrate a possible air-fluid level in the sphenoid sinus
Which facial bones form the posterior aspect of the hard palate?
Horizontal portion of the palatine bones
If the patient cannot stand for the lateral projection of the paranasal sinuses, the projection should be taken with:
Horizontal x-ray beam
Where will the petrous ridges be projected with a 15-degree PA axial (Caldwell) projection of the cranium?
In the lower 1/3 of the orbits
Situation: A radiograph of a PA transoral projection shows that the sphenoid sinus is superimposed over the upper teeth and the nasal cavity. How must the position be modified to avoid this problem during the repeat exposure?
Increase extension of the head and neck to project the entire sphenoid sinus through the oral cavity.
Which facial bone opening has the maxillary branch of the fifth cranial nerve passing through it?
Inferior orbital fissure
Which cranial line is placed parallel to the floor for orthopantomography of the mandible?
Infraorbitomeatal line (IOML)
What is the name of the passageway between the maxillary sinuses and the middle nasal meatus?
Infundibulum
What specific positioning error has been committed if both sides of the mandible are superimposed with an axiolateral oblique projection?
Insufficient cephalic CR angle or skull tilt
A radiograph of an SMV projection of the skull shows that the mandibular condyles are within the petrous bone. Which specific positioning error led to this problem?
Insufficient extension of the skull, or central ray was not perpendicular to IOML
Situation: A radiograph of an axiolateral oblique projection of the mandible shows that the body of the mandible is severely foreshortened. The body of the mandible is the area of interest. What positioning error led to this radiographic outcome?
Insufficient rotation of the skull toward the IR. The skull should be rotated 30 degrees (from lateral position) toward the IR to prevent foreshortening of the body.
Where are the petrous ridges located on a well-positioned parietoacanthial projection?
Just below the maxillary sinuses
Which facial bone is associated with the tear ducts?
Lacrimal bones
Which single projection for a paranasal sinus routine provides an image of all four sinus groups?
Lateral
Where should the CR exit for both the PA parietoacanthial (Waters) and the PA transoral (open-mouth Waters) projections?
Level of the acanthion
The modified parietoacanthial (modified Waters) projection requires that the __________________________ line is perpendicular to the image receptor, which places the OML at a __________________________-degree angle to the tabletop and image receptor.
Lips-meatal; 55-degree
What is the largest immovable bone of the face?
Maxilla
An infection of the teeth may travel upward and involve the __________________________ sinus.
Maxillary
For a parietoacanthial (PA Waters) projection, the petrous ridges should be projected directly below the __________________________ and projected into the lower half of the maxillary sinuses or below the __________________________ for a modified Waters projection.
Maxillary sinuses; inferior orbital rims
Which positioning line is placed perpendicular to the image receptor for a parietoacanthial projection?
Mentomeatal line (MML)
The parietoacanthial (Waters) projection for the facial bones has the __________________________ line perpendicular to the image receptor, which places the orbitomeatal line (OML) at a __________________________-degree angle to the tabletop and image receptor.
Mentomeatal; 37-degree
Central ray angles and degree of rotation stated for basic skull positions are based on the __________________________ (average) skull, which has an approximate angle of __________________________ between the midsagittal plane and the long axis of the petrous bone.
Mesocephalic, 47 degrees
Where does the CR exit for a 15-degree PA axial (Caldwell) projection for the facial bones?
Nasion
A radiograph of an AP axial (Towne method) projection for the cranium shows that the mid- to lower mandible is cut off and not demonstrated. What should the technologist do?
No repeat exposure is required. Because of elongation of the facial mass with the AP axial projection for the skull, cutting off aspects of the mandible is acceptable.
Situation: A radiograph of a parieto-orbital oblique (Rhese) projection shows that the optic foramen is located in the upper outer quadrant of the orbit. Is this an acceptable image for this projection? If not, what must be done to correct this problem during the repeat exposure?
No. Increase extension of the head and neck. The AML should be placed perpendicular to the IR to ensure that the optic foramen is open and is projected into the lower outer quadrant of the orbit (skull rotation is correct).
Situation: A radiograph of a parietoacanthial (Waters) projection shows that the petrous ridges are projected within the maxillary sinuses. Is this an acceptable image? If not, what must be done to improve the image during the repeat exposure?
No. The petrous ridges should be projected just below the maxillary sinuses. The patient's head needs to be extended more.
Situation: A radiograph of a parietoacanthial projection (Waters method) shows that the petrous ridges are projected just below the maxillary sinuses. What positioning error (if any) is present?
None. The petrous ridges should be below the floors of the maxillary sinuses on a well-positioned parietoacanthial projection.
What is the name of the oval processes found on the occipital bone that helps form the atlanto-occipital joint?
Occipital condyles, or lateral condylar portions
Which structure of the sphenoid bone allows for the passage of the optic nerve and is the actual opening into the orbit?
Optic foramen
Which structures specifically are better visualized on the modified parietoacanthial (Waters) projection as compared with the basic Waters projection?
Orbital rims and orbital floors
Which cranial positioning line is placed perpendicular to the image receptor for a PA or PA axial projection of the mandible?
Orbitomeatal line (OML)
Which facial bone structures are best seen with a parietoacanthial projection?
Orbits including infraorbital rims, bony nasal septum, maxillae, zygomatic bones, and arches
Which imaging system provides a single, frontal perspective of the entire mandible?
Orthopantomography (panoramic tomography)
A radiograph of an AP axial (Towne method) projection for the cranium shows that the posterior arch of C1 is projected within the foramen magnum. The dorsum sellae is superimposed on the posterior arch as well. What is (are) the positioning error(s)?
Overangulation of the CR or excessive flexion of neck
Situation: A patient comes to the radiology department with a clinical history of a deviated bony nasal septum. Which facial bone projections best demonstrate the degree of deviation? (More than one correct answer is possible.)
PA, PA axial, and parietoacanthial projections will demonstrate a possible bony nasal septal deviation.
Situation: A patient with a possible fracture of the nasal bones enters the emergency room. The physician is concerned about deviation of the bony nasal septum along with possible fracture of nasal bones. What radiographic routine would be best for this situation?
Parietoacanthial and R and L lateral projections. The parietoacanthial (Waters method) or the optional PA axial projections would demonstrate any possible septal deviation. The lateral projections would demonstrate any possible fracture of the nasal bones or anterior nasal spine. (The superoinferior tangential projection would provide an axial perspective but is considered an optional projection in most departments and not part of the routine unless specifically requested.)
Situation: A patient with a possible fracture of the left zygomatic arch enters the emergency room. Neither the AP axial nor the SMV projection demonstrates the left side well. The radiologist is indecisive as to whether this zygomatic arch is fractured. What other projections can the technologist provide to better define this area?
Perform the oblique inferosuperior (tangential) projections. These projections are ideal to demonstrate a depressed fracture of the zygomatic arch. (Bilateral projections are generally taken for comparison.)
The vertical plate of the ethmoid bone forming the upper portion of the bony nasal septum is the
Perpendicular plate
Situation: A patient with a possible linear fracture of the right parietal bone enters the emergency room. Which single radiographic projection of the skull best demonstrates this fracture?
Right lateral projection of the skull
A radiograph of an AP axial (Towne method) projection of the cranium shows that the right petrous ridge is wider than the left side. Which specific positioning error is present on this radiograph?
Rotation of skull present; rotation of patient's face toward left
A radiograph of a 15-degree PA axial (Caldwell) projection demonstrates that the distance between the right midlateral orbital borders and lateral margin of the skull cortex is greater than the left side. Which positioning error led to this radiographic outcome?
Rotation of the patient's face (skull) to the left
1. Situation: A radiograph of a lateral projection of the facial bones shows that the mandibular rami are not superimposed. What positioning error led to this radiographic outcome?
Rotation of the skull
Situation: A radiograph of a parietoacanthial (Waters) projection shows that the distance between the lateral margins of the orbits and the lateral aspect of the cranial cortex is not equal. What type of positioning error led to this radiographic outcome?
Rotation of the skull
Situation: A radiograph of a parietoacanthial projection shows that the distance between the midsagittal plane and the outer orbital margin is not equal. What positioning error is present on this radiograph?
Rotation of the skull
For a patient with possible trauma, what must be determined before performing the submentovertical (SMV) projection of the skull?
Rule out any possible cervical fractures or subluxation.
Which projection of the mandible demonstrates the entire mandible, including the coronoid and condyloid processes?
SMV projection
A deviated nasal septum is most likely to occur at the junction between __________________________ and __________________________.
Septal cartilage, vomer (pushed laterally to one side)
Situation: A patient comes to the radiology department for a skull series, but the patient cannot assume the correct position for either version of the AP axial (Towne method) projection because of a very short neck and severe spinal kyphosis. What can the technologist do to demonstrate the occipital bone?
Should perform the PA axial projection (Haas method)
A radiograph of a lateral projection of the skull shows that the orbital plates are not superimposed. (One orbital plate is slightly superior to the other.) Which specific positioning error led to this radiographic outcome?
Skull tilt
Which sinuses are projected through the oral cavity with the PA axial transoral projection?
Sphenoid sinuses
Which paranasal sinuses are demonstrated with an SMV projection of the paranasal sinuses?
Sphenoid, ethmoid, and maxillary sinuses
Situation: A patient comes to the radiology department to rule out a possible polyp within the sphenoid sinus. What routine and/or special projection provides the best overall assessment of the sinuses for this patient?
The PA transoral special projection in addition to the routine four sinuses projection series (the lateral, PA Caldwell, parietoacanthial, and SMV)
Situation: A lateral radiograph of the facial bones demonstrates that the bodies of the mandible are not superimposed; one is about 1 cm superior to the other. How would this be corrected on a repeat exposure?
The head was tilted. Ensure that the MSP is parallel to the image receptor.
Situation: A patient with a clinical history of sinusitis comes to the radiology department for a sinus study. The patient is quadriplegic and cannot be placed erect. Which single projection demonstrates any possible air-fluid levels in the sinuses?
The most diagnostic projection is the horizontal beam lateral projection to demonstrate any air-fluid levels.
What is the one major difference in positioning between the parietoacanthial and PA axial transoral projections?
The mouth (oral cavity) is open with the PA transoral projection.
Situation: A radiograph of an SMV projection for sinuses shows that the distance between the mandibular condyles and lateral border of the skull is not equal. What specific positioning error is present on this radiograph?
Tilt of the skull
What positioning error has been committed if the EAMs are not superimposed with one of them more superior than the other on a lateral projection of the cranium?
Tilt of the skull
Which external landmark corresponds with the level of the petrous ridge? __________________________
Top of the ear attachment (TEA)
A "free-floating" zygomatic bone is the frequent result of a __________________________ fracture.
Tripod
1. True/False: The PA axial projection of the mandible produces an elongated view of the condyloid processes.
True
Which small membrane marks the beginning of the middle ear?
Tympanic membrane (eardrum)
Situation: A neonate has a clinical history of craniosynostosis. Because of the age of the patient, the physician does not order a radiographic procedure of the cranium. What other imaging modality can be performed to evaluate the patient for this condition?
Ultrasound (sonography)—a noninvasive means of evaluating the newborn's cranium
Situation: A radiograph of a 30-degree PA axial projection of the facial bones shows that the petrous ridges are projected at the level of the inferior orbital margins. Is this an acceptable image for this projection? If not, what must be done to improve the quality of the image during the repeat exposure?
Yes, this image meets the evaluation criteria for a 30-degree PA axial projection.
Which specific facial bone structures (other than the mandible) are best demonstrated with the submentovertical (SMV) projection if the correct exposure factors are used (soft tissue technique)?
Zygomatic arches
Which facial bones are sometimes called the "cheek bones"?
Zygomatic or malar bones
Which structures of the sphenoid bone help to form part of the lateral walls of the nasal cavities?
medial and lateral pterygoid processes
