115 terms

Ch.12 Skull

Midsagittal plane
Interpupillary line
supraorbital groove
top of ear attachment
external auditory meatus
internal auditory meatus
supraorbital margin
infraorbital margin
glabelloaveolar line
glabellomeatal line
orbiomeatal line
infraorbitalmeatal line
acanthiomeatal line
lipsmeatal line
mentomeatal line
A radiograph of an AP axial proj of the crania reveals that the dorsum sellae is projected below the foramen magnum, but the anterior arch of C1 is visible w/i the foramen. WHich of the following positioning errors led to this radiographic outcome?
a. excessive CR angle
b. insufficient CR angle
c. insufficient flexion of the head and neck
d. tilt of the skull
A radiograph of a PA axial proj (Caldwell) of the cranium reveals that the petrous ridges are located at the level of the lower one third of the orbits. The tech performed this proj with the CR angled 15 degree caudal to the OML. How must positioning be altered if a repeat exposure is performed?
a. increase the extension of the skull
b. increase the flexion of the skull
c. increase the CR angle
d. none; position correct
A radiograph of a smv proj of the cranium reveals that the mandibular condyles are proj into petrous pyramids. What must be altered during teh repeat exposure to produce a more diagnostic radiograph?
a. increase extension of skull
b. increase flexion of skull
c. decrease CR angle
d. none acceptable image
A radiograph of a lateral proj of the cranium reveals that the orbital plate are not superimposed, one is slightly superior to the other. WHich of the following position error led to this outcome?
a. rotation
b. tilt
c. excessive flexion
d. excessive extension
A radiograph of a lateral cranium reveal that the mentum was cut off from the bottom of the radiograph. A 10x12 was used and it was placed crosswise. What must be altered if a repeat exposure is performed?
a. center CR at EAM
b. use 14x17
c. place cassett lengthwise
d. none; center and ir correct
A patient comes to radiology for a routine study of the cranium. He is unable to flex his head and neck sufficiently to place OML perpendicular to the IR for AP axial proj. What should the tech do to compensate for this problem w/o creating excess magnification of the occipital bone?
a. use IOML w/ CR angle of 37 degree
b. perform Haas
c. Perform smv proj
d. use AML and increase CR angle by 10 degree
Pt enters ER w possible basilar skull fracture. Which of the following skull proj would best demonstrate any blood present in the sphenoid sinus?
a. AP w/15 degree cephalic angle
b. Haas method
c. SMV
d. Horizontal beam lateral proj
Pt comes to radiology with a history of a possible erosion of the superior orbital fissures. Which of following prom would best demonstrate this structure?
a. PA axial w/ a 15 degree caudal angle to OML
b. SMV
c. PA axial w/ 25 to 30 degree caudal angle to OML
d. AP axial w/ 37 degree caudal angle to OML
Pt comes to radiology w/ possible bone cyst w/i the squamous portion of frontal bone. Which of the following proj would best demonstrate this region w/ a minimal amt of distortion of the frontal bone?
a. AP axial w/ 30 degree caudal angle to OML
b. PA axial w/ 30 degree caudal angle to OML
c. PA axial w/ 15 degree caudal angle to OML
d. PA w/ no angle to OML
Pt comes to radiology for study of the sella turcica. Which of the following routines would best demonstrate this structure?
a. PA axial w/ 15 caudal angle and lateral proj
b. AP axial and lateral proj
c. SMV and lateral proj
d. Haas and SMV
Pt comes to radiology w/ clinical history of an acoustic neuroma. Which of hte following imaging modalities will provide the best assessment for this tumor?
a. Radiography
b. Ultrasound
c. Nuclear Medicine
d. MRI
Pt comes to radiology w/ severe mastoiditis. WHich of the following imaging modalities will best demonstrate possible bony destruction w/i the mastoid region?
a. CT
b. Nuclear Medicine
c. Ultrasound
d. MRI
Pt comes in w clinical history of a possible pituitary adenoma. Because this is a rural hospital, CT and MRI are not available. Which radiographic proj or position would best demonstrate signs of erosion of sella turcica because of tumor?
a. AP axial Towne
b. PA Caldwell
c. Lateral
d. SMV
Small flap of cartilage covering the opening to the ear (EAM)
This method requires a 25 degree cephalad angle
The CR is centered 2" superior to EAM for this proj
AP axial proj w/ 30 degree caudal CR to IOML for sella turcica best visualizes what?
anterior clinoid processes
The eustachian tube attaches to this part of ear
The widest portion of the cranium is found at the level of _______.
parietal tubercles
The joint found btwn lateral condylar portions of the skull and the superior articular process of C1
atlantooccipital joint
This cranial bone makes up the majority of the calvarium
Name the suture that separates the parietal from the occipital bone
This division of the temporal bone contains the organs of hearing and equilibrium
The classification of an average shape skull with a 47 degree angle btwn petrous pyramids and midsagittal plane
This central portion of bony labyrinth contains the oval window
The degree of angluation for Caldwell
The cranial bone that possesses the zygomatic process
For PA proj of skull, which positioning line is perpendicular to IR?
The mastoid air cells communicate with this part of the ear
Hereditary disease which involves excessive spongy bone formation of the middle and inner ear
If pt is unable to depress chin sufficiently to bring OML perpendicular to IR the IOML can be placed perpendicular w/ CR caudad angle of _____ degrees
This proj results in the highest thyroid dose of all skull proj
The sensory apparatus of both equilibrium and hearing are contained in this part of ear
Lesions of decreased density
This is an alternative proj for pt who cant flex their neck sufficiently for AP axial (Towne)
An opening btwn the epitympanic recess and the mastoid air cells
This disease is characterized by a "cotton-wool" appearance radiographically
This structure includes cochlea, vestibule, and semicircular canals
osseous labyrinth
The frontal bone articulates with how many cranial bones
This bony landmark represents the highest level of facial bone mass
orbital plates
This fontanel is last to close at about 18 months of age
The frontal, sphenoid and occipital bone all articulate with which other bone
This fracture is sometimes called a ping-pong fracture
This landmark corresponds with the level of petrous ridge
This proj requires that the IOML is placed parallel to the IR
The left mastoid fontanel becomes the _____________ in an adult
Left asterion
This cavity is part of the middle ear
The PA proj of the skull requires how many degrees of angluation?
This kV range is recommended for all skull proj
The ethmoid notch is part of this bone
This cranial bone possesses the zygomatic process
The difference btwn the infraorbiomeatal and orbitomeatal line is about ___ degrees
This modality best demonstrates early signs of Paget's disease of the skull
Nuclear medicine
This bone forms a protection for the pituitary gland
The structure of the inner ear responsible for hearing
This bone contains the foramen ovale
This cranial bone possesses the superior nasal conchae
This cranial bone articulates with ALL other cranial bones
For a PA axial proj of skull, which positioning line is perpendicular to IR
What is total number of fontanels in an infant?
Small irregular bones occasionally found in cranial sutures
For a lateral proj of the skull the CR is centered 2" ________ to the EAM
This bone contains the cribriform plate
This anatomy should be shielded when possible
The anterior fontanel found in the adult skull and what bones does it connect
bregma (f & p)
posterior fontanel found in adult skull and what connects
lambda (p & o)
right sphenoid fontanel found in adult and what connect
rt pterion (p,t,s)
left sphenoid fontanel found in adult and what connect
left pterion (p,t,s)
right mastoid fontanel found in adult and what connect
right asterion (p,t,o)
left mastoid fontanel found in adult and what connect
left asterion (p,t,o)
frontal and parietal
2 parietal
occipital and parietal
parietal and temporal
47 degrees, width btwn 75-80% length
>47 degrees, width 80%-more length
<47 degrees, width <75% length
AP Axial
80 20
30 degree caudad to OML chin depressed
37 degree caudad to IOML no depression
CR 2 1/2" above glabella
Lateral Skull
80 8
MSP parallel IR, IPL perpendicular IR, IOML perpendicular edge IR
CR 2" superior to EAM
PA Axial
80 18
OML perpendicular IR, exit @ nasion
15 degree caudad, petrous ridge low 1/3 orbits
25-30 degree caudad, petrous ridge below orbits
PA 0 degrees
80 18
OML perpendicular IR, exit @ glabella
CR perpendicular IR (parallel to OML)
Petrous ridge fill orbits and superimpose supraorbital region
80 30
IOML parallel IR perpendicular CR
CR 1 1/2" inferior mandibular symphysis midway btwn gonion
PA Axial
80 20
OML perpendicular IR, 25 degree cephalad to OML
CR to MSP pass through level of EAM exit 1 1/2" sup to nasion
(can't do AP towne, magnifies occipital region but lower thyroid dosages)
Lateral: Sella Turcica
80 10
IPL perpendicular table, MSP parallel table, IOML perpendicular front IR
CR 3/4" ant 3/4" sup EAM, 4" sq collimation
AP Axial: Sella Turcica
80 22
IOML perpendicular IR
37 degree caudad if dorsum sellae and post clinoid process interest w/i foramen magnum
30 degree caudad if ant clinoid process interest above foramen magnum
CR 1 1/2" above superciliary arch exit @ foramen magnum
Linear fracture
jagged or irregular lucent lines
Depressed fractures
ping-pong, fragment of bone separate and depressed into cavity
basal skull fractures
through dense inner structures of temporal bone, see air fluid levels in sphenoid sinus use horizontal lateral, CT
destructive lesions w/ irreg margins
proliferative bony lesion of increase density
Combo blastic and lytic
moth-eaten appearance
multiple myeloma
tumor originate in bone marrow
pituitary adenomas
tumor of pituitary seen by CT or MRI, images show enlargement of sella turcica and erosion of dorsum sellae
paget's disease (osteitis deformans)
bony destruction then bony repair, radiographically area of lucency demonstrate destructive stages, cotton-wool appearance w/ irreg area of increase density.
Seen with nuclear medicine best
bacterial infection of mastoid process, mastoid air cell fill with fluid abscess, CT
acoustic neuroma
benign tumor of auditory nerve sheath, CT or MRI
benign cystlike mass or tumor in middle lear or mastoid region destroy bone
hereditary disease w/ excessive spongy bone formation of middle and inner ear, late adolescence or young adult, CT
Bones apart of calvaria (skullcap)
frontal, right and left parietal, occipital
Bones apart of floor
right and left temporal, sphenoid, ethmoid