Chapter 7 Flashcards
(170 cards)
1
Q
Bony anatomy is always more reliable as a positioning criterion than what?
A
Soft tissue organs
2
Q
The skeleton criteria for a particular of the body is shared by what?
A
Any procedures done in that area.
3
Q
The bones of the lumbar spine and pelvis can be used to evaluate any abdominal position including what views?
A
IVP, cystogram, barium enema, upper GI, or a gallbladder series.
4
Q
While attention to the projection of particular organs is sometimes important, by focusing primarily on the skeletal criteria we are able to what?
A
Simplify the rules of film critique.
5
Q
All __________ procedures can be combined.
A
Thoracic
6
Q
All abdominal and _______ views can be combined.
A
Pelvic
7
Q
And most of the what can be discussed collectively in selecting criteria to evaluate positioning?
A
Spinal vertebrae
8
Q
For the PA or AP view of the chest or bilateral ribs, the symmetry of what is typically recommended as the criterion for rotation?
A
Sternoclavicular joints
9
Q
These 2 joints (sternoclavicular) should be equidistant from what and locates by what?
A
Equidistant from the midline if the spine and located by the teardrop-shaped spinous process, as shown in figure 76-A.
10
Q
Figure 76-B although the sternoclavicular joints, are only slightly rotated, the base of the lungs in this view are what?
A
Are grossly asymmetrical in length along the diaphragm.
11
Q
SC Joints only indicate what?
A
The shoulders.
12
Q
It is possible to have the shoulders straight and the hips crooked, resulting in what?
A
Rotation only at the bases of the lungs.
13
Q
For a perfectly straight view, costophrenic angles of the lungs should also appear what?
A
equidistant from the midline of the spine.
14
Q
On normal patients, this is achieved by ensuring what?
A
That one foot is not placed in front of the other.
15
Q
There is great variation in the distance from the mid-spine to the sternoclavidular joints, depending on what
A
The thickness and size of the patient.
16
Q
On average, the SC joints are approximately how many inches?
A
3/4 of an inch to either side of the patient.
17
Q
One quarter inch of sideways shift for these joints equates to what
A
About 5 degrees of rotation in the shoulders.
18
Q
With 5 degrees of rotation, one SC joint would be about what?
A
A 1/2 inch from the spinous process, while the opposite joint would be an inch from the mid spine.
19
Q
Ideally, the scapulae should be completely desuperimposed from what?
A
The lung fields for a PA chest projection.
20
Q
This is accomplished by rotating the shoulders forward until what?
A
Until both are in contact with the table, chest board or cassette.
21
Q
In practice, the medial borders of the scapulae may superimpose what?
A
The upper lateral lung fields along the inner borders of the ribs by a small amount.
22
Q
When both shoulders are rotated forward equally, this helps what?
A
Helps to eliminate any rotation of the chest itself and the sternoclavicular joints will be symmetrical.
23
Q
If one scapula overlaps the lung field more than the opposite one, then what??
A
Both shoulders were not rotated forward evenly.
24
Q
Angulation and Flexion/Extension
Routine chest and rib views require what??
A
No angulation of the X-ray beam.
25
On the medial aspects of the 1st 3 posterior ribs will be demonstrated where?
Above the clavicles as shown in Figure 76-B.
26
On same patients the third rib will be what?
Partially covered by the clavicle as in Figure 76-A.
27
For intentional lordotic views of the chests proper angle of the X-ray beam or extension of the spine will produce what?
A view with the clavicles projected over the medial aspects of the 1st posterior ribs and completely above the apices of the lungs.
28
It is common when performing AP chest projections such as “stretcher chests” or portable chests, to obtain what?
Improper lordotic views from insufficient caudal angulation of the x-ray beam.
29
Such views will demonstrate the clavicles above the posterior third ribs and tend to cause a what?
A "straightened out" linear appearance to the posterior ribs from the distortion of their normal curvature.
30
This problem is avoided by ensuring that the central ray is angled sufficiently caudal to be what?
Perpendicular to the mid-axillary line of the patient rather than perpendicular to the film, bed or stretcher.
31
Small children's skulls are much larger in proportion to their what?
Their bodies than those of adults.
32
It does not take very much flexion or extension of the neck to get the what?
To get the chin or the occipital bone of an infant over the apices of the lungs.
33
When lying an infant on it's back, the large cranium resting against the table often forces what to happen
The chin into a flexed position, superimposing it over the lung fields.
34
To avoid this (as well as to avoid a lordotic projection) place a 10-15 degree angle sponge on top of the cassette to accomplish what?
With the thickest end under the baby's shoulders, allowing the head to fall gently back onto the film.
35
Dropping the head off of the sponge and film or using a thicker sponge may do what?
Hyperextend the head and injure the child.
36
Normal frontal views of the chest on adult patients should be on full inspiration, with what showing?
Ten posterior ribs showing in the lung fields
37
To consider a rib as being in the lung field, at leas what must appear?
The medial one half of the posterior rib should appear above the diaphragm.
38
This same rule applies for what?
the above-the-diaphragm projections of the ribs
39
Figure 80 is an example of inadequate inspiration, and shows how to count what?
The ribs
40
For infants in general, how many ribs above the diaphragm is adequate?
Nine.
41
For premature and newborn infants, how many ribs above the diaphragm is adequate?
Eight.
42
When adequate penetration is used for chest radiography, details of the thoracic spine and medial ribs will be what?
Just visible through the heart shadow, as in Figure 76.
43
Proper density will then also demonstrate the what?
Soft tissue markings in the lung fields.
44
A chest radiograph is repeatable any time what happens?
Any time that the mediastinal structures are obliterated by inadequate penetration or density, leaving the heart and spine area with a white or clear appearance.
45
The lateral view of the chest has no what?
No pairs of reliable anatomy close to the central ray.
46
In assessing rotation, we are limited to using what?
Using anatomy along the back of the chest, which is less variable than the anterior chest wall.
47
The right and left posterior ribs should be what?
Superimposed directly on top of each other, and the right and left costophrenic angles should also superimpose each other.
48
Figure 82 shows that when the lateral chest view is rotated what appears?
A space of lung field will appear between the sets of ribs, usually with one set of ribs showing the circular on end appearance from looking down at them.
49
As a rule of thumb, if this space is more than what?
Two finger-breadths wide, the view should be repeated.
50
On lateral views, one inch of shift between the ribs indicates what?
About 5 degrees of rotation, since one side shifts forward by 1/2 inch and the opposite side shifts backward 1/2 inch
51
The posterior costophrenic angles in figure 82 are shifted by the same amount as what?
As the ribs, and are reliable indicators of rotation.
52
Note that there is a normal long space that lies behind what?
Lies behind the spine, between it and the posterior ribs.
53
Some patients have very curved ribs so that this space is large, an appearance that can be mistaken for what?
Rotation even though the posterior ribs are exactly superimposed, figure 83.
54
Be careful not to mistake this normal space behind as what?
A space between two sets of ribs.
55
During lateral chest projections, a common error is what?
To fold the patient's hands on top of his head, rather than his arms.
56
Views like that in figure 83 can result in what?
With arm tissue superimposing the lateral lung field.
57
Whenever possible, the patients forearms should be what.
Crossed over his head.
58
Asking the patient to keep his chin up also helps him what?
Stand straight, and on large patients this can make a difference in fitting the lung fields on the film.
59
In figure 84 a large patient's anterior costophrenic angles were clipped off when he did what.
When he leaned back upon taking a deep breath, extending the spine.
60
The same rule used for the PA chest, of demonstrating ten ribs above the diaphragm, also applies to what?
The evaluation of adequate inspiration on the lateral chest view.
61
One must observe the position of the uppermost peak of what?
The dome of the diaphragm and count the number of posterior ribs which lie above that point.
62
When a proper 45 degree oblique view is taken of the chest or ribs, the posterior ribs on one side will appear to be what?
One half as long as those on the opposite side as in figure 85
63
Also, the sternum will be shifted so that there is a what?
A 2-3 inch space between it and the spine.
64
When the rotation is too shallow, the space between the sternum and spine will be less than what?
Two inches and the foreshortened lung will not yet be reduced to one-half.
65
When the rotation is too steep, the foreshortened lung will be reduced to less than what?
One half the width of the opposite lung, and the view will begin to take on a distinct rotated lateral appearance
66
For coned down oblique views of the right or left ribs, the posterior ribs on the side of interest are what?
Laid out roughly parallel to the film, so that they appear long and somewhat straightened, while those on the opposite side are foreshortened and very curved.
67
For posterior oblique positions, the side of interest is the downside.
For anterior oblique positions, the side of interest is the upside.
68
Ideally on the side of interest the heads of most of the ribs dont what?
Do not superimpose the bodies of the vertebrae. If they do, the position is too steep.
69
Decubitus views of the chest should meet all of the criteria for what?
Routine frontal views.
70
In addition, it is essential that the arms be placed above the patient's what?
There head so there is no chance of superimposing them over the lung fields.
71
If free air such as a pnemothorax, is to be ruled out, the upside is what?
Should be the side of interest and must be included.
72
The right anterior oblique position of the sternum or of the sternoclavicular joints should be what?
A shallow 15-20 degree angle of rotation.
73
This ideally projects the sternum just off of the spine, and over the what?
The heart shadow, figure 86.
74
If there is more than one inch of space between the sternum and the spine, what happens?
The position is too steep.
75
If any portion of the sternum overlaps the spine, what is it?
The position is too shallow.
76
For oblique views of the sternum, shallow steady breathing is recommended, what will demonstrate what?
Blurred trabecular soft tissue markings of the lung fields.
77
The lateral view of the sternum should show the sternum squarely what?
Sideways, with no rib shadows extending in front of it.
78
For the thin ribs or sternum, a lower penetration technique is required when what?
When compared to chest radiography.
79
Using 70-76 kVp will produce what?
High contrast visualization of these delicate bones as in figure 86.
80
The easiest and most reliable criteria for determining rotation on what?
Any abdominal views, including urography and barium enema radiographs are the bones of the pelvis.
81
The flat alae, or crests, of the iliac bones lie at an oblique angle, do what?
Extend laterally as they project forward.
82
Figure 88-C shows how, if an abdominal view is rotated, one Crest will do what?
Always appear narrower than the opposite Crest due to foreshortening distortion.
83
Note that the broader Crest also will begin to roll around behind what?
The fifth lumbar vertebra, so that on the radiograph it appears to run into the spine, figure 88-C.
84
When an abdominal or pelvic radiograph is unrelated, the iliac crests will appear symmetrical and there will be a small space where?
Between them and the fifth lumbar vertebra symmetrically on both sides as shown in figure 88-A.
85
Generally, when the patient is in a rotated supine position, what will be foreshortened?
The upside down iliac Crest will be foreshortened, but the upside obturator foramen will be opened up as shown in figure 89-A.
86
Both the iliac crests and the obturator foramina lie at about 35 degree angles from the what?
The coronal plane of the torso on average, so that 35 degrees of rotation opens the foramen and 55 degrees places the Crest on end.
87
Thirty five degrees of rotation will fully open. The upside obturator foramen, with the downside being what.
Quite foreshortened as shown in B.
88
At 45 degrees of rotation, the upside Crest now forms a narrow looped appearance and is almost on end.
Fifty five degrees of rotation places the upside iliac crest is placed fully on end as in D.
89
For abdominal radiographs generally, one should try to include all anatomy from what?
From the diaphragms to the public bone.
90
One exception to this rule would be those radiographs taken, during what?
The first five minutes of an IVP series, which must be centered to include the entire kidneys.
91
In order to demonstrate any free peritoneal air rising up under the diaphragm, what happens
All upright views of the abdomen must include both entire hemidiaphragms.
92
This requires centering three to four inches above what?
Above the level of the iliac crests, depending on how talk the patient is.
93
Most decubitus views of the abdomen are taken to rule out free abdominal air.
Therefore, in addition to the preceding criteria, collimation and centering must be such that the upside of the abdomen is the side of interest.
94
Technique on all abdominal and pelvic views should be set for what?
Optimum penetration of the bones, showing the spinouts processes and particles visible through the bodies of the vertebrae.
95
The proper amount of rotation for views of rotation for views of what?
The sacroiliac joints is 25-30 degrees, so that positioned correctly, the upside iliac crest will take on a crossed over or looped appearance just as discussed.
96
In an upper GI series, a 30-45 degree LPO position opens the C-loop of the duodenum somewhat.
The duodenal C-Loop is opened best with a very steep.
97
The only common angled view of abdominal anatomy l is that of the what?
The sigmoid colon during for a barium enema, which employs a 35- degree cephalic angle of the CR.
98
Beside the above overview, good positioning texts describe other what?
Other important anatomical relationships, such as the placement of barium or air, recognizing different positions.
99
Our purpose here, however, is to what?
Critique the positions
100
Because of the great variation in location and shape of soft tissue organs, they are not what?
Not very useful for film critique.
101
The appearance of the spine and other bony anatomy is a what?
A more reliable indicator of the exact body position.
102
It should be noted, however, that the presence of any distinct fluid levels indicates what?
That a horizontal x-ray beam was used.
103
The position can then be recognized as either an upright or a decubitus position by remembering what?
That fluids will settle according to gravity.
104
By remembering that the higher of the two colonic flexures is the what?
Splenic flexure on the left
105
The sigmoid colon extends to the left from the what?
Rectum, one can further determine which specific decubitus position was used as in figure 98.
106
Even when a vertical beam is used and no distinct fluid levels are present, one can determine what?
On a double-contrast study with barium and air whether a patient is supine or prone, in RPO or LAO or in LPO or RAO position by knowing the anatomy and observing the pooling of barium there indicates a supine or posterior oblique position.
107
All of the vertical portions of the colon lie _______, while the transverse and sigmoid colons lie ________.
Posterior
| Anterior
108
Therefore, pooling of barium in the ascending and descending colon and the rectum indicate what?
A supine or posterior oblique position as shown figure 95.
109
It should be noted, however, that the presence of any what?
Any distinct fluid levels indicates that a horizontal x-ray beam was used.
110
Even when a vertical beam is used and no distinct fluid levels are present, what can one determine?
We can determine on a double contrast study with barium and air whether a patient is supine or prone.
111
For renal procedures, in the 30 degree posterior oblique position, the upside kidney is placed where?
Nearly parallel to film providing an unobscured view of the ureteral pelvis, and the downside kidney is in profile.
112
For oblique views during cystourethrography, the rotation of the torso should be what?
Somewhat steeper than for renal procedures.
113
For urethrography, male patients often require a similar amount of what?
Steep obliquity in order to desuperimpose the prostatic and proximal penile urethra from the bladder floor, but for female urethrography, 35 to 40 degrees of rotation is recommended.
114
A twisting rotation frequently occurs during positioning because patients will favor what?
An injured hip or shoulder and tend to raise that side off of the x-ray table to relieve pressure.
115
Whenever contrast agents are used, the ideal level of penetration is such that some details can be seen through what
The bolus of contrast agent.
116
For urography, the distal ureters should be seen coursing behind the upper portion of what?
The contrast-filled bladder, and ureteral stones or kinks should be seen within the ureters.
117
The presence of stool in the colon or food in the stomach can what?
Obscure the visibility of biliary or renal anatomy, Figure 102.
118
The general appearance of the vertebrae can be used not only to critique views of the lumbar, thoracic, and cervical spines, but also to what?
Critique any chest or abdominal radiographs that include vertebrae within the field of view.
119
Although the three portions of the spine each have unique vertebral features, at least what is universal as criteria.
At least two anatomical parts are fairly universal as criteria for critiquing rotation.
120
On a straight, unrotated frontal view of most vertebrae, the spinous process can be seen on what?
On end as an oval or teardrop-shaped feature exactly in the midline of the vertebral body.
121
In the lumbar spine, the transverse processes are prominent and rotation will cause what?
Cause the appearance of one overlapping the vertebral body more than the other.
122
On good 45-degree obliques of the lumbar spine, the apophyseal joints will do what?
Will open and appear as dark slits running through the vertebral bodies, and the familiar scotty dogs will be most recognizable as in Figure 108
123
Scoliosis causes a twisting of the spine, shifting it to what?
The spinous process to one side on an AP radiograph.
124
A twisting rotation frequently occurs during positioning because patients will favor what?
An injured hip or shoulder and tend to raise that side off of the x-ray table to relieve pressure.
125
For spine radiography, the primary aim of angling the central ray cephalic or caudal, employing what?
Spinal flexion, or extending the head is to desuperimpose vertebrae off of each other in the superior/inferior axis.
126
On the lateral views of the sacrum and coccyx, the posterior margins should be what?
The posterior margins of the ischia should be nearly superimposed.
127
Lateral views of all spines should be show the vertebral bodies clear of what?
Any superimposing facets or processes.
128
On lateral views of the thoracic spine, a cephalic angle of 5-10 degrees is frequently required on road-shouldered or narrow-waisted patients in order to compensate for what?
The tilt created, place the central ray perpendicular to the spine, and open the intervertebral joint spaces.
129
For the lumbosacral joint, the coned-down spot lateral view of the joint frequently requires what?
A 5-10 degree caudal tube angle, but not always
130
If the routine lateral view of the lumbar spine is processed and available prior to what?
Exposing the L5-S1 spot, the need for an angle can be determined from it as follows:
131
Remember that when centered at or above the iliac crest, those rays which pass through the L5-S1 joint on the lateral view are what?
Diverging, angled rays located several inches below the central ray.
132
On good 45-degree obliques of the lumbar spine, the apophyseal joints will do what?
Will open and appear as dark slits running through the vertebral bodies, and the familiar scotty dogs will be most recognizable as in Figure 108,
133
For the AP views of the sacrum and coccyx, the sacroiliac joints should be seen as what?
Equidistant from the midline spinous processes of the sacrum, the obturator foramina should appear symmetrical, and the symphysis puis will be aligned with the spinous processes of the spine and sacrum in the middle.
134
The 15- degree cephalic beam angle recommended for the AP view of the sacrum is designed for what?
To minimize the foreshortening distortion that occurs when projecting angled anatomy with a vertical beam.
135
Superimposition of the occipital bone over what?
The odontoid process, shown in Figure 117, indicates hyperextension of the head.
136
On the lateral views of the sacrum and coccyx, the osterior margins should be what?
The posterior margins of the ischia should be nearly superimposed.
137
For all but the uppermost cervical vertebrae, the spinous processes and the pedicles can be used for what?
Rotation criteria just as described for the thoracic and lumbar spines.
138
The lordotic curvature of te cervical spine causes all but the top two of these vertebra to slant what?
Downward,and a cephalic angle of 15 to 20 degrees is required to desuperimpose them.
139
There are two possible causes for the chin being projected into C-3.
The first is failure to use a cephalic tube angle as just described.
140
Adequate extension of the head during positioning is achieved when what hapens?
The under-surface of the body of the mandible is almost perpendicular to the film
141
The correct combination of tube angle and head extension will result in what?
The bottom of the chin and the bottom of the occipital bone being directly superimposed over each other.
142
The open-mouth odontoid view is a special case, involving the positioning of the head.
With no rotation of the head, the upper and lower molar teeth will appear equidistant from the midline of the odontoid process.
143
Proper flexion/extension of the head will place the bottom edges of the upper central incisor teeth directly over what?
Over the bottom edge of the occipital bone, as in Figure 116.
144
The upper teeth may be properly superimposed over what?
The occipital one, yet if the lower molar teeth obscure the body of C-2 as in Figure 116, then the mouth was not opened wide enough.
145
On obliques of the cervical spine, the intervertebral foramina will open and appear as what?
Oval holes that are nearly round as shown in Figure 118
146
Rotation of the head on oblique cervical spine projections is a controversial issue.
Although positioning atlases recommend that the head be in line with the rest of the body, this can result in the ramus of the mandible superimposing C-2 as in figure 118.
147
Obliques of the cervical spine which are adequate for evaluation of trauma can be taken if necessary without what?
The recommended 15-20 degree beam angle, but the intervertebral foramina will not be opened up as well vertically.
148
The lateral views of the cervical spine should show what?
The vertebral bodies clear of any superimposing processes.
149
The lateral view of the cervical spine utilizes no tube angle, but both shoulders must be what?
Depressed enough to desuperimpose the seventh cervical vertebra.
150
The twining view, properly done, should be as near lateral as possible without what?
Superimposing either shoulder over the cervicothoracic vertebrae.
151
On all frontal and oblique views of the spines, there should be minimal lateral bending, and if the patient is not placed diagonally what happens?
On the table, the spine should be aligned vertically down the center of the view.
152
A fairly high contrast image is desirable for what?
Spine radiography, using kVp levels from 70-80 for adults.
153
The transverse processes should be visible on frontal and what else?
Oblique views, and the spinous processes on lateral views.
154
Breathing technique should be used for the lateral thoracic spine, blurring what?
The soft tissue markings in the lung fields so that the spine can be better seen through them.
155
In nonrotated frontal views, the distal phalanx of each finger will appear as what?
Appears symmetrical with equal concavity on either side.
156
In rotated or oblique views, the anterior side of each phalanx will appear as what?
Will appear more concave than the posterior side, but the distal phalanx will still have a base.
157
For the oblique hand position, the proper 45 degrees of rotation will seperate the mid-shafts of what?
All metacarpals, even though the bases and heads of these bones will typically overlap as in Figure 125-A.
158
If there is diagnostic interest in the digits, what must be done to place them parallel?
Oblique hand views must be done with all of the fingers fully extended to place them parallel to the film.
159
It must be noted that some departments allow flexion of what?
Flexion of the digits for oblique hand views, provided there is no direct interest in the digits.
160
Lateral views of the hand, including the fanned lateral, should demonstrate what?
The second, third, fourth, and fifth metacarpals superimposed directly upon each other or stacked.
161
On the fanned lateral view of the hand, the flexion of the digits should be what?
Such that all four fingers are equally spaced, with the second digit touching or nearly touching the thumb.
162
On any lateral view of a digit or a fanned lateral of what?
A hand, all interphalangeal joints should be open.
163
Closing of these joints on lateral views indicates what?
A lateral tilt to the finger.
164
The special ball catcher's position to demonstrate arthritis requires that the fingers be where?
Left in their natural amount of flexion with the hands placed in semisupination.
165
The interphalangeal joints will thus be what?
Closed off in appearance, but the metacarpophalangeal joints should be open.
166
On the nonrotated PA view of the wrist, the distal radioulnar joint space should be what?
Open, with no overlappin of the radius and ulna.
167
If any portion of the distal radius and ulna superimpose, what is present?
Rotation is present?
168
A primary purpose of the oblique wrist position is to what?
Desuperimpose the trapezium and trapezoid which overlap on the frontal view as shown i figure 124.
169
Approximately one quarter of the head of the ulna will superimpose the radius.
If more than one quarter of the ulnar head overlaps teh radius, or if the mid shafts of the metacarpals in the hand overlap as in Figure 125-B the position is too steep more than 45 degrees.
170
With normal anatomy, a true lateral view of the wrist will place what?
The smaller head of the ulna in the middle of the broader base of the radius.
