RAD 230: Bontrager Ch 11 Workbook - Skull

Which one of the following bones is not part of the floor of the cranium...

A. Temporal..

B. Ethmoid...

C. Occipital...

D. Sphenoid

Occipital

Which aspect of the frontal bone is thin-walled and forms the forehead

squamous

What four cranial bones articulate with the frontal bone

right parietal, left parietal, sphenoid, and ethmoid

Which structures are found at the widest aspect of the skull

parietal tubercles of two parietal bones

What is the name of a prominent landmark (or bump) found on the external surface of the occipital bone

external occipital protuberance (inion)

List the number of individual bones that articulate with the following cranial bones...

Parietal bone...

Occipital bone...

Temporal bone..

Sphenoid...and

Ethmoid

5 for parietal..

6 for occipital..

3 for temporal..

7 for sphenoid..and

2 for ethmoid

What is the thickest and densest structure in the cranium

petrous portion

True or False: The hypophysis is another term for the pituitary gland

True, hypophysis cerebri

True or False: The sphenoid bone articulates with all the other cranial bones

true

The shallow depression just posterior to the base of the dorsum sellae and anterior to the foramen magnum is the

clivus

Which small section of the bone is located superior to the cribiform plate

crista galli

What is the formal term for the left sphenoid fontanel in the adult

left pterion

What is the name of the cranial suture formed by the inferior junction of the parietals to the temporal bones

squamosal suture

What are the two terms for the small, irregular bones found in the adult skull sutures

sutral, or wormian

These following bones are within what structure....

pterygoid hamulus, anterior clinoid processes, foramen ovale, and sella turcica

sphenoid

These following bones are within what structure....

glabella and supercilliary arch

frontal

These following bones are within what structure....

perpendicular plate, superior nasal conchae, and cribiform plate

ethmoid

These following bones are within what structure....

foramen magnum, lateral condylar portions, and inion

occipital

These following bones are within what structure....

zygomatic proces, EAM, and petrous ridge

temporal

Which one of the following skull classifications applies to a skull with an angle of 54° between the midsagittal plane and the long axis of the pars petrous

brachycephalic

Which of the preceding classifications is considered the average-shaped skull

mesocephalic

What landmark corresponds to the highest level of the petrous ridge

TEA

Reid's base line is an older term for

IOML

How much of a difference in degrees is there between the OML and IOML

7 to 8 degree difference

Which one of the following positioning errors frequently results in a repeat exposure of a cranial position...

A. Rotation..

B. Incorrect CR placement..

C. Slight flexion..

D. Slight extension

rotation

Condition that begins with bony destruction followed by bony repair

Paget's disease

Tangential view may be helpful to determine extent or degree of this fracture

depressed fracture

What clinical indication may require a decrease in manual exposure factors

multiple myeloma

Which aspect of the temporal bone is considered to be the thinnest

squamous portion

Which aspect of the temporal bone contains the organs of hearing and balance

petrous pyramid or pars petrous

Which two projections of the cranium project the dorsum sellae within the foramen magnum

AP axial Towne and PA axial Haas

How much central ray angle is required for the AP axial projection Towne method for skill with the IOML perpendicular to the image receptor.....

What is the central ray angle for this same projection with a perpendicular OML

37 degree caudad...

30 degree caudad

Where is the central ray centered for a lateral projection of the cranium

2 inches superior to EAM

To prevent tilting of the skull for the lateral projection of the cranium, the _________ line is placed perpendicular to the IR

interpupillary

Where should the petrous ridges be located (on the image) for a well-positioned, 25 degree caudad PA axial Haas projection

superior to mastoid processes and symmetrical

Where is the central ray centered for an SMV projection of the skull

1 1/2 inch inferior to mandibular symphysis

Which positioning line is parallel to the IR for the SMV projection of the skull

IOML

SITUATION: A radiograph of an AP axial projection for the cranium reveals that the dorsum sellae is projected superior to the foramen magnum. What must be modified during the repeat exposure to correct this problem

increase CR angle approximately 7 degree caudad

SITUATION: A radiograph of a lateral projection of the cranium reveals that the greater wings of sphenoid are not superimposed. What type of positioning error is present on this radiograph

rotation

SITUATION: A radiograph of a 15 degree caudad PA axial projection of the cranium reveals that the petrous ridge are at the level of the supraorbital margin. Without changing the central ray angle, how must the head position be modified during the repeat exposure to produce a more acceptable image

increase extension of the skull to place the OML perpendicular to the IR (will project ridges into lower 1/3 of orbits)

SITUATION: A patient with a possible basilar skull fracture enters the emergency room. The physician wants a projection to demonstrate a possible sphenoid sinus effusion. Which projection of the cranium is best for this situation

Horizontal beam (dorsal decubitus) lateral skull projection

SITUATION: The same patient with the possible basilar skull fracture requires a frontal projection of the skull. The physician wants the projection to demonstrate the frontal bone and place the petrous ridges in the lower 1/3 of the orbits, but it has not been determined whether the patient's cervical spine has been fractured, so the patient cannot be moved from a supine position. What should the technologist do

perform the AP projection with a 15 degree cephalad CR angle to the OML

SITUATION: A patient comes to the radiology department for a skull series. Because of the size of the patient's shoulders, he is unable to flex his neck sufficiently to place the OML perpendicular to the IR for the AP axial projection. His head cannot be raised because of possible cervical trauma. What other options does the technologist have to obtain an acceptable AP axial projection

use IOML instead and increase CR angle to an additional 7 degree caudad

SITUATION: A radiograph of an AP axial Towne projection for cranium reveals that the posterior arch of C1 and dorsum sellae are superimposed. Both are projected into the foramen magnum. What modification is needed to correct this error present on the initial radiograph

decrease CR angle based on the skull line used, OML 30 degree; IOML 37 degree

SITUATION: A radiograph of a lateral skull demonstrates that the orbital plates (roof) of the frontal bone are not superimposed. What is the positioning error present on this radiograph

tilt of the skull

SITUATION: A radiograph of an AP axial Townes for cranium reveals that the left petrous portion of the temporal bone is wider than the right. What is the specific positioning error present on this radiograph

rotation to the right

SITUATION: A radiograph of a SMV projection of the cranium demonstrates that mandibular condyles are projected into the petrous portion (pyramids) of the temporal bone. How must the position be altered during the repeat exposure to correct this error

extend the skull further to place the IOML parallel to the IR

True or False: In general, all the paranasal sinuses are fully developed by the age of 6 or 7 years

False, fully developed in late teens (ethmoid develops last)

The sphenoid sinus lies directly inferior to the

sella turcica

Which single projection of the facial bones best demonstrates any possible air-fluid levels in the sinuses if the patient cannot stand or sit erect

horizontal beam lateral projection

Shape description for the classification of the skull:

Mesocephalic

Width between 75% & 80% of length

Shape description for the classification of the skull:

Brachycephalic

Width ≥80% of length

Shape description for the classification of the skull:

Dolichocephalic

Width <75% of length

CR angles & degree of rotation stated for basic skull positions are based on the ________ (average) skull, which has an approximate angle of _______ between the midsagittal plane & the long axis of the petrous bone

Mesocephalic, 47 degrees

The long, narrow-shaped skull has an angle of approximately _______ degrees between the midsagittal plane & the long axis of the petrous bone

+/- 40

True/False: 2 older terms for the orbitomeatal line (OML) are Reid's base line & the anthropologic base line

False (There are other terms for the infraorbitomeatal line)

There is a _____-degree difference between the orbitomeatal & infraorbitomeatal lines, & _____ degrees between the orbitomeatal & glabellomeatal lines

7-8 degrees for both

A line between the infraorbital margin and EAM

IOML

Corresponds to the highest "nuchal" line of the occipital bone

Inion

A line between the glabella & alveolar process of the maxilla

Glabelloalveolar line

A line between the mental point and EAM

mentomeatal line

Located at the junction of the 2 nasal bones & the frontal bone

Nasion

Corresponds to the highest level of the facial bone mass

Supraorbital groove

A line between the midlateral orbital margin and the EAM

OML

The center point of the EAM

Auricular point

A positioning line that is primarily used for the modified Waters projection

Lips-meatal line

A line used in positioning to ensure that the skull is in a true lateral position?

Interpupillary line or IPL

Corresponds to the level of the petrous ridge

TEA (top of ear attachment)

A smooth, slightly depressed area between the eyebrows

Glabella

What is the average kV range for digital skull imaging?

80-90

List the 5 common errors made during skull radiography

A. Rotation

B. Tilt

C. Excessive neck flexion

D. Excessive neck extension

E. Incorrect CR angulation

Of the 5 most common error, which 2 are most common?

A. Rotation

B. Tilt

Bilateral horizontal fractures of the maxillae describe a ________ fracture

A. Le Fort

B. Blowout

C. Tripod

D. Contrecoup

A. Le Fort

Which of the following imaging modalities is the most common neuroimaging procedure performed for the cranium?

A. CT

B. Ultrasound

C. MRI

D. Nuclear medicine

A. CT

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

Fracture that may produce an air-fluid level in the sphenoid sinus

Basal skull fracture

Clinical indication described:

Also called a "ping-pong" fracture

Depressed skull fracture

A tumor that may produce erosion of the sella turcica

Pituitary adenoma

AKA osteitis deformas

Paget's disease

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

Which cranial bone is best demonstrated with an AP axial (Towne method) projection of the skull?

Occipital

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

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

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. CR angle

C. Flexion or extension

D. Rotation

D. Rotation

If the patient cannot flex the head adequately for the AP axial (Towne method) projection, the technologist could place the ________ perpendicular to the IR & angle the CR _______ degrees caudad

IOML, 37

What evidence on a an AP axial (Towne method) radiograph indicates whether the correct CR angle & correct flexion were used?

Dorsum sellae & posterior clinoids should be projected into the foramen magnum

What CR angle should be used for the PA axial (Haas method) projection of the cranium?

25 degrees cephalad

Where is the CR centered for a lateral projection of the skull?

2 inches above the EAM

Which specific positioning error is present if the mandibular rami are not superimposed on a lateral skull radiograph?

A. Tilt

B. Rotation

C. Overflexion

D. Incorrect CR angle

B. Rotation

Where will the petrous ridges be projected with a 15-degree PA axial (Caldwell) projection of the cranium?

In the lower one-third of the orbits

Which 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

Which projection of the cranium produces an image of the frontal bone with little or no distortion?

0 degree PA

For a patient with possible trauma, what must be determined before performing the SMV projection of the skull?

Rule out any possible cervical fractures or subluxation

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 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 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 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

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 does the CR exit for a PA axial (Haas method) projection of the skull?

A. 1.5 inches superior to the nasion

B. 3/4 inch anterior to the EAM

C. 2.5 inches above the glabella

D. Level of nasion

A. 1.5 inches superior to the nasion

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