Chapter 11 Skull & Cranial Bones Workbook
53. The long, narrow-shaped skull has an angle of approximately ___________ degrees between the midsagittal plane and the long axis of the petrous bone.
+/- 40
73. What is the central ray centered for a lateral projection of the skull?
2 (5 cm) inches superior to EAM or halfway between the glabella and inion
1. Fill in the total number of bones. A. Cranium __________ B. Facial bones ___________
A. 8 B. 14
85. Which imaging modality is best to differentiate between an epidural and subdural hemorrhage? A. CT B. MRI C. Nuclear medicine D. PET
A. CT
42. Which of the auditory ossicles resembles a premolar tooth?
Incus
13. Which structures of the sphenoid bone help to form part of the lateral walls of the nasal cavities?
Medial and lateral pterygoid processes
79. What position 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
34. Which small membrane marks the beginning of the middle ear?
tympanic membrane (eardrum)
77. Which projection of the cranium produces an image of the frontal bone with little or no distortion?
0° posteroanterior (PA)
Sutures A. Coronal B. Squamosal C. Lambdoidal D. Sagittal Asterions E. Bregma F. Lambda G. Right and left pterion H. Right and left asterion Fontanelles: associated adult asterion I. Anterior (Bregma) J. Posterior (Lambda) K. Right and left sphenoid (Pterions) L. Right and left mastoid (Aterions)
16. Identify the four major sutures and the six associated asterions and fontanelles labeled on these drawings of an adult cranium and an infant cranium (Figs. 11.11 to 11.14):
57. What is the average kV range for analog skull radiography? kV for digital imaging?
75-85 kV (analog) and 80 to 90 kV (digital systems)
92. A lateral skull radiograph demonstrates one mandibular ramus about 0.5 cm more anterior than the other. Which positioning error occurred?
Skull rotation
39. What is the name of the thin plate of bone that separates the mastoid air cells from the bone?
Tegmi tympani
94. 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
11. The posterior aspect of the Sella turcica is called the _________________.
Dorsum sellae
71. What evidence on the 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
20. What is the name of the notch that separates the orbital plates from each other?
Ethmoidal notch
36. Which structure allows for communication between the nasopharynx and the middle ear?
Eustachian or auditory tube
26. True/False: The mastoid portion of the temporal bone is the densest of the three aspects of the temporal bone.
False (petrous portion)
46. True/False: The semicircular canals include a closed system specific to the sense of hearing.
False (sense of equilibrium)
54. True/False: Two older terms for the orbitomeatal line (OML) are Reid's base line and the anthropologic base line.
False (these are the other terms for the infraorbitomeatal line.)
17. Cranial sutures are classified as being _____________ joints.
Fibrous or synarthrodial
28. Which opening in the temporal bone serves as a passageway for nerves of hearing and equilibrium?
Internal acoustic meatus
14. Which radiographic projection best demonstrates the Sella turcica and dorsum sellae?
Lateral projection
24. 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
32. Which structure makes up the cartilaginous external ear?
Auricle or pinna
63. Which of the following imaging modalities is most commonly performed to evaluate patients Alzheimer disease? A. CT B. Ultrasound C. MRI D. Nuclear medicine
D. Nuclear medicine
69. 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
52. Central ray angles and degree of rotation stated for basic skull position 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
33. How long is the average external acoustic meatus (EAM)?
1 inch (or 2.5 cm)
56. 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 the 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 mid-lateral 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
1. G - Outer canthus 2. E - Gonion 3. J - Infraorbitomeatal line (IOML) 4. N - Inion 5. H - Glabelloalveolar line 6. K - Mentomeatal line 7. D -Nasion 8. F - Tragus 9. B - Supraorbital groove 10. I - OML 11. O - Auricular point 12. L - Lips-meatal line 13. C - Interpupillary line 14. A - TEA 15. M - Glabella
72. What central ray angle should be used for the PA axial (Haas method) projection for the cranium?
25° cephalad
A. Frontal B. Right parietal C. Right temporal D. Sphenoid E. Ethmoid F. Left temporal G. Left parietal H. Occipital
4. Identify the cranial bones labeled in Figs. 11.1 and 11.2:
A. B. C. D. E. F. G. H. I. J.
47. Identify the structures labeled in Fig. 11.17. (A-J)
A. Frontal B. Ethmoid C. Sphenoid D. Left temporal E. Left parietal F. Occipital G. Right parietal H. Right temporal
5. Identify all eight bones on the two superior-view drawings (Figs. 11.3 and 11.4): (A-H)
A. Crista Galli ("Rooster Comb") B. Cribriform plate C. Perpendicular plate D. Lateral labyrinth E. Middle nasal conchae (turbinate)
6. Identify the labeled parts on the three views of the ethmoid bone (Figs. 11.5 and 11.6): (A-E)
55. 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)
A. Anterior clinoid process B. Lesser wing C. Greater wing D. Sella turcica E. Dorsum sellae F. Posterior clinoid process G. Clivus Foramina (H-L) H. Foramen rotundum I. Foramen ovale J. Foramen spinosum K. Foramen magnum L. Optic foramen M. Lateral pterygoid process (plate) N. Pterygoid hamulus O. Medial pterygoid process (plate) P. Superior orbital fissure Q. Body of sphenoid (sinus)
9. Identify the labeled parts on the four views of the sphenoid in Figs. 11.7 through 11.10: (A-Q)
64. 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 lesions 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
A. (3) Basal skull fracture B. (5) Osteolytic neoplasm C. (6) Depressed skull fracture D. (1) Osteoblastic neoplasm E. (2) Pituitary adenoma F. (4) Paget's disease G. (7) Multiple myeloma
84. Where does the CR exit for a PA axial (Haas method) projection of the skull? A. 1 ¹/₂ (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. 1¹/₂ (4 cm) superior to the nasion
48. Match each of the following clinical indications for the temporal bone to the correct definition or description (Use each choice only one. Pathology of temporal bone found on p. 402.) A. Neoplasia B. Otosclerosis C. Mastoiditis D. Acoustic neuroma E. Polyp F. Cholesteatoma 1. Bacterial infection of the mastoid process 2. Growth arising from a mucous membrane 3. Hereditary disease involving excessive bone formation of the middle ear 4. Benign, cystic mass or tumor of the middle ear 5. New and abnormal growth 6. Benign tumor of the auditory nerve sheath
A. 5 B. 3 C. 1 D. 6 E. 2 F. 4
66. 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
61. 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)
49. Which of the following radiographic appearances pertains to an acoustic neuroma? A. Expansion of the internal acoustic canal B. Bone destruction within the middle ear C. Increased density to the incus D. Sinus mucosal thickening
A. Expansion of the internal acoustic canal
2. List the four cranial bones that form the calvaria (skullcap). A. B. C. D.else
A. Frontal B. Right parietal C. Left parietal D. Occipital
44. Which two sensory functions occur within the inner ear? A. _____________ B. _____________
A. Hearing B. Equilibrium
60. Bilateral horizontal fractures of the maxillae describe a ______________ fracture. A. Le Fort B. Blowout C. Tripod D. Contrecoup
A. Le Fort
51. List the three classifications of the skull; then match them with the correct shape description listed. Classification Shape Description A. ______________ a. Width <75% of length B. ______________ b. Width >/= 80% of length C. ______________ c. Width between 75-80% of length
A. Mesocephalic (c) B. Brachycephalic (b) C. Doliocephalic (a)
67. 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 IR? A. OML B. IOML C. GAL D. AML
A. OML
3. List the four cranial bones that form the floor of the cranium. A. B. C. D.
A. Right temporal B. Left temporal C. Sphenoid D. Ethmoid
59. Of the five most common errors made during skull radiography, which two are the most common? A. ____________ B. ____________
A. Rotation B. Tilt
58. List the five most common errors made during skull radiography. A. B. C. D. E.
A. Rotation B. Tilt C. Excessive neck flexion D. Excessive neck extension E. Incorrect central ray angulation
25. List the three aspects of the temporal bones. A. B. C.
A. Squamous B. Mastoid C. Petrous
30. List the three aspects of the temporal bone. A. B. C.
A. Squamous B. Mastoid C. Petrous
38. Which structure serves as an opening between the mastoid portion of the temporal bone and the middle ear?
Aditus
35. What is the collective term for the small bones of the middle ear?
Auditory ossicles (malleus, incus, and stapes)
50. Which of the following imaging modalities best demonstrates otosclerosis? A. Nuclear medicine B. CT C. Conventional radiography D. Sonography
B. CT
74. 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
62. 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
68. 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
83. Which of the following projections best demonstrates the clivus in profile? A. AP axial B. 15-degree PA C. Lateral D. SMV
C. Lateral
93. 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.
7. The small horizontal plate of the ethmoid seen on Fig 11.6, is called the _________________.
Cribriform plate
82. Which of the following projections best demonstrates the foramen rotundum? A. SMV B. 25-30° AP axial C. 25-30° PA axial D. Lateral
D. 25-30° PA axial
80. 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
D. IOML
81. 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
99. 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
87. A radiograph of a 15° 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)
76. 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 CR angle
23. A small prominence located on the squamous portion of the occipital bone is called the _____________.
External occipital protuberance, or inion
97. 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
70. 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
75. Where will the petrous ridges be projected with a 15-degree PA axial (Caldwell) projection of the cranium?
In the /3 of orbits; supraorbital margins without superimposition
89. 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
40. Which of the auditory ossicles picks up sound vibrations from the tympanic membrane?
Malleus
101. 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 the elongation of the facial mass with the AP axial projection for the skull, cutting off aspects of the mandible is acceptable
22. Which cranial bone contains the foramen magnum?
Occipital
65. Which cranial bone is best demonstrated with an AP axial (Towne method) projection of the skull?
Occipital
12. Which structure of the sphenoid bone allows for the passage of the optic nerve and is the actual opening into the orbit?
Optic foramen
15. Which aspect of the frontal bone forms the superior aspect of the orbit?
Orbital or horizontal portion
43. What is the name of the small membrane that connects the middle to the inner ear?
Oval or vestibular window
100. 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 the head
8. The vertical plate of the ethmoid bone forming the upper portion of the bony nasal septum is the ________________.
Perpendicular plate
31. Which aspect of the temporal bone is considered the densest?
Petrous portion
21. Which cranial bones form the upper lateral walls of the calvarium?
Right and left parietals
95. 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
86. 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
88. A radiograph of a 15° PA axial (Caldwell) projection demonstrates that the distance between the right midlateral orbital borders and lateral margins 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
45. What is the name of the small membrane found at the base of the cochlea (two possible terms)?
Round or Cochlear window
78. For 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
A structure found in the middle of the sphenoid bone that surrounds the pituitary gland is the _____________.
Sella turcica
90. 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
41. Which of the auditory ossicles is considered the smallest?
Stapes
19. Which term describes the superior rim of the orbit (Include the abbreviation also.) _______________
Supraorbital margin (SOM)
18. 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
37. What is the major function of the structure described in 36 (eustachian tube)?
TO equalize the atmospheric pressure within the middle ear
96. 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 sever spinal kyphosis. What can the technologist do to demonstrate the occipital bone?
The technologist should perform the PA axial projection (Haas method)
27. Which external landmark corresponds with the level of the petrous ridge?
Top of the ear attachment (TEA)
98. 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
