SKULL positioning Flashcards

1
Q

3 divisions of ear

A
  1. external
  2. middle
  3. internal
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

external ear consists of

A
auricle (pinna) 
tragus 
EAM
mastoid process 
mastoid tip styloid process
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

where does the external ear end

A

at the tympanic membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

where are the location of organs of hearing and equilibrium

A

located in the petrous pyramids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

3 parts of middle ear

A
  1. tympanic membrane
  2. tympanic cavity
  3. auditory ossicles
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q
  1. tympanic membrane
A

partition between external and middle ear

transmits sound vibrations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q
  1. tympanic cavity
A

communicates with nasopharynx by eustachian tube
separated from external ear by tympanic membrane
separated from internal ear by bony labryinth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

the tympanic cavity is further divided into 2 parts

A
  1. tympanic cavity proper

2. epitympanic recess (attic)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

drum crest (spur)

A

bony projection to which tympanic membrane is attatched

separates EAM from epitympanic recess

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

middle ear

A

communicates with nasopharynx and mastoids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

eustachian tube

A

passageway between middle ear and nasopharynx

equalizes pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

internal acoustic meatus

A

smaller than the EAM

best demonstrated with CT and MRI

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

aditus

A

opening between epitympanic recess and mastoid air cells

allows infection in middle ear which may pass to mastoids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

3 auditory ossicles

A
  1. malleus
  2. incus
  3. stapes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

auditory ossicles

A

transmit sound vibrations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

inner ear

A

contains sensory apparatus of hearing and equilibrium

in densest portion of petrous pyramids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

2 parts of the inner ear

A
  1. osseous bony labyrinth

2. membranous labyrinth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

osseous bony labyrinth

A

bony chamber that houses membranous labyrinth

divided into 3 parts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

3 parts of osseous bony labyrinth

A
  1. cochlea
  2. vestibule
  3. semi circular canals
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q
  1. cochlea
A

snail shell
relates to sense of hearing
communicates with middle ear through round window

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q
  1. vestibule
A

communicates with middle ear by way of oval window

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q
  1. semi circular canals
A

anterior
posterior
lateral
relate to direction or equilibrium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what nerves pass through the IAM from membranous labyrinth to the brain

A

cochlear and vestibular nerve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

membranous labyrinth

A

intercommunicating system of ducts and sacs housed in the osseous bony labyrinth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
2 windows of internal ear
1. oval window (vestibular) | 2. round window (cochlear)
26
oval window
receives vibrations from external ear through stapes of middle ear moves inward with vibration
27
round window
allows movement of fluid within the closed duct system of membranous labyrinth moves outward
28
clinical indications of cranium (11)
``` skull fractures gunshot wounds neoplasms multiple myeloma pituitary adenoma paget's disease temporal bone pathology acoustic neuroma cholesteatoma polyp otosclerosis ```
29
1. skull fractures
a. linear fractures b. depressed fractures c. basal skull fractures
30
a. linear fractures
appear as jagged or irregular lucent lines that lie at right angles to the axis of the bone
31
b. depressed fractures AKA ping pong
a fragment of bone is separated and depressed into cranial cavity ex: crushing a ping pong ball dent in it
32
c. basal skull fractures
can be found on a plain radiograph by air fluid level in sphenoid sinus
33
complications of basal skull fractures
leakage of CSF meningitis damage to facial nerve damage to auditory apparatus
34
2. gunshot wounds
plain images will localize bullets
35
3. neoplasms
new/abnormal growths
36
osteolytic
destructive lesions with irregular margins
37
osteoblastic
proliferative bony lesions of increased density
38
combo osteolytic and osteoblastic lesions
eaten appearance
39
4. multiple myeloma
one or more bone tumors that originate in bone marrow
40
5. pituitary adenoma
tumor of pituitary gland usually diagnosed with CT/MRI | plain image show enlargement of sella turcica and erosion of dorsum sellae
41
6. paget's disease
cotton wool appearance | unknown etiology
42
7. temporal bone pathology
mastoiditis - bacterial infection where air cells are replaced with fluid filled abcess
43
8. acoustic neuroma
benign tumor of auditory nerve | originates in IAC
44
9. cholesteatoma
begnign cyst like mass or tumor most common in middle ear or mastoid region destroys bone
45
10. polyp
growth that arises from a mucous membrane and projects into cavity may cause sinusitis
46
11. otosclerosis
abnormal sponge like bone grows in middle ear
47
mesocephalic skull
average head width is 75% to 80% of the length petrous pyramids project anteriorly and medially at a 47 degree angle
48
brachycephalic skull
``` short from front to back broad from side to side shallow from vertex to base width is 80% or greater than the length petrous pyramids have a 54 degree angle ```
49
dolichocephalic skull
``` long from front to back narrow from side to side deep from vertex to base petrous pyramids have a 40 degree angle width is less than 75% of the length ```
50
5 common positioning errors
1. rotation 2. tilt 3. excessive flexion 4. excessive extension 5. incorrect CR angle
51
positioning considerations for asthenic or hyposthenic pt.
build up the body to get cervical vertebra in line with foramen magnum
52
positioning considerations for hypersthenic pt.
build up the head to get cervical vertebra in line with foramen magnum
53
alternative modalities
CT MRI Ultrasound Nuclear med
54
skull series ROUTINE
AP axial (towne method) Lateral PA axial 15 degrees (caldwell) or 25 - 30 degree angle PA 0 degrees
55
Skull series SPECIAL
``` submentovertex (SMV) PA axial (Haas method) ```
56
skull AP axial (towne method) clinical indications
skull fractures medial/lateral displacement neoplastic processes paget's disease
57
Skull AP axial (towne method) technical factors
SID = 40 10 x 12 IR lengthwise 80-85 kv
58
skull AP axial (towne method) pt. / part position
supine or erect OML perpendicular to IR if pt. can't get OML perpendicular place IOML perpendicular CR angle 30 degrees to OML CR angle 37 degrees to IOML CR enters 2.5 inches above glabella to pass through foramen magnum
59
skull AP axial (towne method) what do you see
dorsum sellae and posterior clinoids visualized in the shadow of the foramen magnum
60
skull AP axial (towne method) UNDERANGULATION / INSUFFICIENT FLEXION
projects dorsum sellae superior to the foramen magnum
61
skull AP axial (towne method) OVERANGULATION / EXCESSIVE FLEXION
superimposes the arch of C1 over the dorsum sellae within the foramen magnum
62
are both right and left laterals done for a skull series?
yes
63
lateral skull technical factors
SID = 40 10 x 12 crosswise 80-85 kv
64
lateral skull pt./part position
``` erect or recumbent side of interest closest to IR IPL perpendicular to IR IOML perpendicular to front edge of IR GAL parallel to front edge of IR CR enters 2 inches above EAM or halfway between glabella and inion ```
65
lateral skull rotation evident by:
anterior and posterior separation of symmetric vertical bilateral structures
66
lateral skull tilt evident by:
superior and inferior separation of symmetric horizontal structures