Добавил:
Sekretar
kiopkiopkiop18@yandex.ru
t.me/Prokururor I Вовсе не секретарь, но почту проверяю
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз:
Предмет:
Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_5557_Библиотеки_им_академика_М_И_Перельмана.pdf
114
CHAPTER 5
|
IMAGING PROCEDURES
Temporomandibular Joints
Axiolateral: Law’s Method
Positioning Criteria
• Patient placed in a true lateral position erect or prone
(erect preferred) with affected side closest
• Place an 8⬙ ⫻ 10⬙ (20 ⫻ 25 cm) IR lengthwise in the
Bucky aligned with the central ray
• Adjust IOML to be perpendicular to front edge of IR
• Rotate patient’s head 15 degrees toward the IR
• Central ray directed 15 degrees caudal and 2⬙ (5 cm)
superior to EAM, exiting the down TMJ
• A series of two projections are taken: one with the
mouth closed and one with it open
• Collimate on all four sides
• Minimum SID: 40⬙ (100 cm)
Evaluation Criteria
• Down TMJ seen free of superimposition of contra-
lateral side
• TMJ of interest is centered on image
Demonstrates
• Range of motion between TM fossa and mandibular
condyle
• Closed-mouth image shows mandibular condyle
in fossa, open mouth demonstrates movement of
condyle to anterior margin of the fossa
Axiolateral: Schüller Method
Positioning Criteria
• Patient placed in a true lateral position erect or prone
(erect preferred) with affected side closest to IR; full
lead apron provided
• Place an 8⬙ ⫻ 10⬙ (20 ⫻ 25 cm) IR lengthwise in the
Bucky aligned with the central ray
• Adjust IOML to be perpendicular to front edge of IR,
interpupillary line parallel to IR, and MSP parallel
to IR
• Central ray directed 25 degrees to 30 degrees caudal
at a point 2⬙ (5 cm) superior to EAM, exiting the
down TMJ
• A series of two projections are taken: one with the
mouth closed and one with it open
• Collimate on all four sides
• Minimum SID: 40⬙ (100 cm)
Submentovertical (Full Basal) Mandible
Positioning Criteria
• Patient AP erect and shielded
• 10⬙ ⫻ 12⬙ (25 ⫻ 30 cm) IR lengthwise placed in Bucky
• Patient’s IOML is parallel to IR
• MSP is perpendicular to the IR
• Central ray perpendicular and directed midway
between mandible angles and 1½⬙ (4 cm) inferior to
mandibular symphysis
• Collimate to four sides to include all pertinent
anatomy
• Place appropriate side marker within light field on
lateral aspect of image
• Minimum SID: 40⬙ (100 cm)
Evaluation Criteria
• No rotation or tilt evident by equal distance from
mandible to lateral border of skull
Demonstrates
• Coronoid and condylar process of mandible
• Fractures
Axiolateral Obliques Mandible
Positioning Criteria
• Perform imaging on tabletop with a 15-degree inclined
positioning sponge or, if patient may stand, use Bucky
• Interpupillary line perpendicular to IR
• MSP parallel to IR and IOML parallel to the horizontal
aspect of IR
• Head will be rotated 30 degrees toward receptor;
patient positioning dependent on area of concern
• Central ray will be angled 20 degrees to 25 degrees
cephalic and 2⬙ (5 cm) inferior to up gonion
• This best demonstrates mandibular body
Evaluation Criteria
• Must include: mentum to coronoid, mandibular fossa,
and condyle
• Done bilaterally for comparison
• Side closest to IR/Bucky is the side of interest
Demonstrates
• Body best demonstrated with 30-degree rotation
• Mentum best demonstrated with 45 degrees of rota-
tion
• Rami best demonstrated when head in true lateral
115
CHAPTER 5
|
IMAGING PROCEDURES
Evaluation Criteria
• No rotation noted by symmetrical appearance of
right and left sinuses
• Proper extension of head noted by position of pars
petrosa
Demonstrates
• Nasal septum
• Maxillary sinus free of superimposition from petrous
ridge
• Pathology including but not limited to: displacement
of nasal septum, sinusitis
Lateral Projection: Nasal Bones
Positioning Criteria
• Performed bilaterally
• Patient in an anterior oblique position
• Utilize an 8⬙ ⫻ 10⬙ (20 ⫻ 25 cm) IR crosswise, nongrid;
divide IR in half to expose one lateral on each side;
full lead apron
• Adjust the interpupillary line to be perpendicular to
the IR
• Central ray perpendicular to a point ½⬙ (1 cm) infe-
rior to the nasion
• Use exposure similar to that for a finger
• Minimum SID: 40⬙ (100 cm)
Evaluation Criteria
• Must include nasofrontal suture, all soft tissue, and
anterior nasal spine
Demonstrates
• Fracture of the nasal bones
• Anterior/posterior dislocation of nasal bone
Posteroanterior Caldwell 30 Degrees
Positioning Criteria
• Patient positioned PA against the upright Bucky
• Align OML and MSP perpendicular to IR
• Utilize an 8⬙ ⫻ 10⬙ (20 ⫻ 25 cm) IR lengthwise aligned
with the central ray
• Central ray is directed 30 degrees caudal to exit nasion
• Minimum SID: 40⬙ (100 cm)
Evaluation Criteria
• No rotation of head
• Baseline is correct when petrous ridge is seen below
the inferior margin of the orbit
Demonstrates
• Nasal septum free of superimposition
• Floor of the orbit
Evaluation Criteria
• Down TMJ seen free of superimposition of contra-
lateral side
• TMJ of interest is centered on image
Demonstrates
• Range of motion between TM fossa and mandibular
condyle
• Closed-mouth image shows mandibular condyle
in fossa; open mouth demonstrates movement of
condyle to anterior margin of the fossa
Anteroposterior Axial: Modified Towne
Positioning Criteria
• Patient in the AP position erect or supine; full-body
lead shielding
• Position the OML line perpendicular to IR
• Utilize a 10⬙ ⫻ 12⬙ (25 ⫻ 30 cm) IR lengthwise in the
Bucky aligned with the central ray
• Central ray is directed 30 degrees caudal at a point 2⬙
(5 cm) anterior to EAM
• A series of two projections are taken: one with the
mouth closed and one with it open
• Collimate on all four sides
• Minimum SID: 40⬙ (100 cm)
Evaluation Criteria
• Down TMJ seen free of superimposition of contra-
lateral side
• TMJ of interest is centered on image
Demonstrates
• Range of motion between TM fossa and mandibular
condyle
• Closed-mouth image shows mandibular condyle in
fossa; open mouth demonstrates movement of con-
dyle to anterior margin of the fossa
Nasal Bones
Parietoacanthial Projection for Nasal Bones
Positioning Criteria
• Patient positioned PA either erect or prone; full-body
shielding
• Adjust the patient’s head to bring the MML perpen-
dicular to the IR (OML forms a 37-degree angle to IR)
• Utilize an 8⬙ ⫻ 10⬙ (20 ⫻ 25 cm) IR lengthwise in Bucky
aligned with central ray
• Central ray directed perpendicular to MSP and exit-
ing at the level of acanthion
• Collimate on all four sides appropriate to the anatomy
of interest
• Minimum SID: 40⬙ (100 cm)
116
CHAPTER 5
|
IMAGING PROCEDURES
Demonstrates
• Nasal septum
• Maxillary sinus free of superimposition from petrous
ridge
• Pathology including but not limited to: displacement
of nasal septum, sinusitis
A transoral open mouth Water projection can be per-
formed with the same positioning. Prior to exposure,
patient is instructed to open mouth. This will addition-
ally demonstrate the sphenoid sinus through the mouth.
Posteroanterior Caldwell: 15-Degree
Projection
Positioning Criteria
• Patient positioned PA against the upright Bucky
• Align MSP perpendicular to IR and OML 15 degrees from
horizontal; a radiolucent support between forehead and
upright Bucky may be used to maintain this position
• Central ray is directed perpendicular to exit nasion
• ALTERNATE METHOD: If the Bucky can be tilted
15 degrees, the patient’s forehead and nose can be
supported directly against the Bucky with the OML
perpendicular to the Bucky surface and 15 degrees to
the horizontal central ray
Evaluation Criteria
• No rotation of head
• Baseline is correct when petrous ridge is seen in the
inferior one-third of the orbit
• Frontal sinus is seen (because of angle, cannot assess
air-fluid level)
• Frontal and ethmoid sinus
Paranasal Sinuses
Sinuses function as resonation chambers for the voice,
decrease cranial weight by containing air, and warm
and moisten inhaled air. In order to detect fluid levels,
all sinuses imaging must be performed with a horizontal
beam. Sinuses develop in the following manner:
Maxillary sinus: largest; well aerated at birth; antra
of Highmore
Sphenoidal sinus (can be single) and frontal sinus:
develop at ages 6 to 7 years
Ethmoid sinus: develops at ages 17 to 18 years
Parietoacanthial Projections (Water Projection)
Positioning Criteria
• Patient is positioned PA against the upright Bucky
• Adjust the MML to be perpendicular to IR and aligned
with the central ray (OML forms a 37-degree angle to IR)
• Central ray directed perpendicular to MSP and exiting
at the level of acanthion
• Collimate on all four sides appropriate to the anatomy
of interest
• Minimum SID: 40⬙ (100 cm)
Evaluation Criteria
• No rotation noted by symmetrical appearance of
right and left sinuses
• Proper extension of head noted by position of pars
petrosa
FIGURE 5-26
117
CHAPTER 5
|
IMAGING PROCEDURES
Parietoorbital Oblique Projection:
Optic Foramina (Rhese Method)
Positioning Criteria
• Patient positioned PA against the Bucky; full lead
apron
• Align acanthiomeatal line perpendicular to the IR
• Rotate head 37 degrees; use three-point landing
technique: place chin, cheek, and nose against unit;
MSP 53 degrees to IR
• Utilize an 8⬙ ⫻ 10⬙ (20 ⫻ 25 cm) IR in the Bucky aligned
to the central ray
• Central ray directed perpendicular to 1⬙ (2.5 cm)
superior and 1⬙ (2.5 cm) posterior to top of ear
attachment (TEA) through affected orbit
• Collimate on all four sides
• Minimum SID: 40⬙ (100 cm)
Evaluation Criteria
• Optic canal visualized in the lower inner quadrant of
the orbit seen in profile
Demonstrates
• Optical canal and optical foramen
• Bony abnormalities of the optic foramen
Anteroposterior Toes
Positioning Criteria
• Instruct the patient to flex the knee and place the
plantar surface of the foot in contact with the IR
• Long axis of the anatomy of interest should be aligned
with the long axis of the IR
• Center the metatarsophalangeal joint of the digit of
interest to the IR
• A sandbag may be used to prevent the IR from sliding
• In order to ensure that the anatomy of interest is
parallel to the IR, either:
Direct the central ray 15 degrees caudal to enter at
the metatarsophalangeal joint OR
Elevate the foot 15 degrees on a wedge-shaped
radiolucent positioning sponge
• Collimate to include from the distal phalanx to at least
the distal half of the metatarsal; include a portion of
the adjacent digits as well
Evaluation Criteria
• Digit of interest visualized in an AP view with a por-
tion of the adjacent digits and no superimposition of
adjacent structures
• No rotation of the foot (equal concavity on both sides
of the phalanges and metatarsals)
Demonstrates
• Air-fluid levels in the frontal and anterior ethmoid
sinuses (see Figure 5-25)
Lateral Projection Sinuses
Positioning Criteria
• Patient in an anterior oblique position with the side
of interest closest to IR; full lead apron
• Align the interpupillary line to be perpendicular and
MSP parallel to the IR
• IOML is parallel to the floor
• Utilize 8⬙ ⫻ 10⬙ (20 ⫻ 25 cm) IR lengthwise in upright
Bucky aligned with central ray
• Central ray perpendicular to a point 1⬙ (2.5 cm) pos-
terior to outer canthus of the eye
• Collimate from the EAM forward and from the bottom
lip to the top of the skull
• Minimum SID: 40⬙ (100 cm)
Evaluation Criteria
• No rotation evident noted by superimposition of the
anterior and posterior clinoid processes as well as
the infraorbital margins
Demonstrates
• All four sinuses: frontal, ethmoid, maxillary, and
sphenoid
Submental Vertex (SMV/Basilar) Projection
Positioning Criteria
• Patient positioned AP against the upright Bucky
• Instruct patient to hyperextend to a point that brings
the IOML parallel and MSP perpendicular to IR
• Utilize an 8⬙ ⫻ 10⬙ (20 ⫻ 25 cm) IR lengthwise in the
Bucky aligned to the central ray
• Central ray is directed perpendicular to IOML at a
point 1⬙ (2.5 cm) anterior to EAMs
Evaluation Criteria
• No rotation noted by symmetrical petrous pyramids
• Mandibular condyles projected anterior to petrous
ridges
Demonstrates
• Ethmoid, sphenoid, and maxillary sinuses and nasal
fossae
Orbits
A series of projections are taken to demonstrate the
orbits, including a parietoacanthial projection. The posi-
tioning for this projection is the same as for sinuses.
118
CHAPTER 5
|
IMAGING PROCEDURES
• A sandbag may be used to prevent the IR from sliding
• Central ray directed perpendicular to metatarsopha-
langeal joint of the digit of interest
• Collimate to include from the distal phalanx to at
least the distal half of the metatarsal; include a por-
tion of the adjacent digits as well
Evaluation Criteria
• Digit of interest visualized in an oblique view with a
portion of the adjacent digits and minimal superim-
position of adjacent structures
• Increased concavity on one side of each phalanx and
metatarsal
Demonstrates
• Digit of interest from the distal phalanx to at least the
distal half of the metatarsal
• Open interphalangeal and metatarsophalangeal joints
Lateral Toes
Positioning Criteria
• Rotate the affected lower extremity medially for the
1st, 2nd, or 3rd digit and laterally for the 4th or 5th digit
• Long axis of the anatomy of interest should be aligned
with the long axis of the IR
• Center the interphalangeal joint (for 1st digit) or proxi-
mal interphalangeal joint (for 2nd to 5th digits) to the IR
• Gauze or tape may be used to separate the toes and
minimize superimposition
• A sandbag may be used to prevent the IR from sliding
• Direct the central ray to the interphalangeal joint (for
1st digit) or proximal interphalangeal joint (for 2nd to
5th digits) of the digit of interest
• Collimate close to the digit of interest; include
from the distal phalanx to the distal portion of the
metatarsal
Evaluation Criteria
• The digit of interest visualized in a lateral view with
no superimposition
• No superimposition of the phalanges
• Metatarsophalangeal joint must be demonstrated,
even if superimposition exists
Demonstrates
• Digit of interest from the distal phalanx to the distal
portion of the metatarsal
• Open interphalangeal joints and possible slight
superimposition of the metatarsophalangeal joint
• Anterior/posterior displacement of fracture fragments
would be demonstrated in the lateral projection
Demonstrates
• Digit of interest from the distal phalanx to at least the
distal half of the metatarsal
• Open interphalangeal and metatarsophalangeal joints
Anteroposterior Oblique Toes
(Medial Rotation)
Positioning Criteria
• Medial rotation is performed for the 1st, 2nd, and
3rd digits
• Instruct the patient to flex the knee and place the
plantar surface of the foot in contact with the IR
• Long axis of the anatomy of interest should be aligned
with the long axis of the IR
• Center the metatarsophalangeal joint of the digit of
interest to the IR
• Oblique the foot 30 degrees to 45 degrees medially
(a radiolucent angle sponge may be used to minimize
patient motion)
• A sandbag may be used to prevent the IR from sliding
• Central ray directed perpendicular to metatarsopha-
langeal joint of the digit of interest
• Collimate to include from the distal phalanx to at
least the distal half of the metatarsal; include a por-
tion of the adjacent digits as well
Evaluation Criteria
• Digit of interest visualized in an oblique view with a
portion of the adjacent digits and minimal superim-
position of adjacent structures
• Increased concavity on one side of each phalanx and
metatarsal
Demonstrates
• Digit of interest from the distal phalanx to at least the
distal half of the metatarsal
• Open interphalangeal and metatarsophalangeal joints
Anteroposterior Oblique Toes
(Lateral Rotation)
Positioning Criteria
• Lateral rotation is performed for the 4th and 5th digits
• Instruct the patient to flex the knee and place the
plantar surface of the foot in contact with the IR
• Long axis of the anatomy of interest should be aligned
with the long axis of the IR
• Center the metatarsophalangeal joint of the digit of
interest to the IR
• Oblique the foot 30 degrees to 45 degrees laterally
(a radiolucent angle sponge may be used to minimize
patient motion)
119
CHAPTER 5
|
IMAGING PROCEDURES
• Open joint space between the 1st and 2nd cuneiforms
(medial and intermediate cuneiforms)
Demonstrates
• All phalanges, interphalangeal joints, metatarsopha-
langeal joints, metatarsals, and cuneiforms are dem-
onstrated in addition to the cuboid and navicular
• Because of superimposition, the talus and calcaneus
are not visualized well in this projection
Anteroposterior Oblique Foot
(Medial Rotation)
Positioning Criteria
• Instruct the patient to flex the knee and place the
plantar surface of the foot in contact with the IR
• Long axis of the anatomy of interest should be aligned
with the long axis of the IR
• Center the foot to the IR
• Oblique the foot 30 degrees to 40 degrees medially
(a radiolucent angle sponge may be used to minimize
patient motion)
• A sandbag may be used to prevent the IR from sliding
Anteroposterior Foot
Positioning Criteria
• Instruct the patient to flex the knee and place the
plantar surface of the foot in contact with the IR
• Long axis of the foot should be aligned with the long
axis of the IR
• Center the base of the 3rd metatarsal to the center
of the IR
• A sandbag may be used to prevent the IR from sliding
• Direct the central ray 10 degrees posteriorly to enter
at the base of the 3rd metatarsal
• Patients with pes cavus (high arches) may require a
larger angle (approximately 15 degrees)
• Patients with pes planus (flat feet) may require a
smaller angle (approximately 5 degrees)
• Collimate close to the anatomy to include the entire foot
Evaluation Criteria
• No rotation of the foot
• Bases of the 1st and 2nd metatarsals are free of
superimposition
• Bases of the 3rd to 5th metatarsals superimposed
FIGURE 5-27
120
CHAPTER 5
|
IMAGING PROCEDURES
• Long axis of the anatomy of interest should be aligned
with the long axis of the IR
• Center the foot to the IR
• Oblique the foot 30 degrees laterally (a radiolu-
cent angle sponge may be used to minimize patient
motion)
• Sandbags may be used to prevent the IR from sliding
• Central ray directed perpendicular to enter the base
of the 3rd metatarsal
• Collimate close to the anatomy to include the entire
foot
Evaluation Criteria
• The entire foot is demonstrated with slight superim-
position of the digits
• Superimposition at the bases of the 1st to 5th metatarsals
Demonstrates
• The medial portions of the 1st cuneiform and navicu-
lar are demonstrated
• Central ray directed perpendicular to enter the base
of the 3rd metatarsal
• Collimate close to the anatomy to include the
entire foot
Evaluation Criteria
• Base of the 1st and 2nd metatarsals are superimposed
• Entire 3rd to 5th metatarsals free of superimposition
Demonstrates
• The entire foot, including all phalanges, interphalan-
geal joints, metatarsophalangeal joints, metatarsals,
and tarsals
• The cuboid, 3rd (lateral) cuneiform, sinus tarsi, and
base of the 5th metatarsal are well visualized in this
projection
Anteroposterior Oblique Foot
(Lateral Rotation)
Positioning Criteria
• Instruct the patient to flex the knee and place the
plantar surface of the foot in contact with the IR
FIGURE 5-28
121
CHAPTER 5
|
IMAGING PROCEDURES
Lateral Foot (Mediolateral)
Positioning Criteria
• Patient is positioned lateral recumbent onto affected
side
• Flex knee and place lateral portion of the foot in
contact with the IR
• Adjust the long axis of the foot in line with the long
axis of the IR and center the foot to the IR
• The plantar surface of the foot should be perpendicu-
lar to the IR
• Instruct the patient to slightly dorsiflex the foot if
possible
• Direct the central ray perpendicular to the midpor-
tion of the foot at the level of the base of the 3rd
metatarsal
• Collimate close to the anatomy to include the entire
foot and approximately 1⬙ (2.5 cm) of the distal tibia
Evaluation Criteria
• As compared to the lateromedial lateral projection of
the foot, this projection is easier for the patient to
attain
• The entire foot from the superimposed phalanges to
the calcaneus is demonstrated
• The distal fibula is superimposed by the posterior
portion of the tibia and the tibiotalar joint space
is open
Demonstrates
• The calcaneus and talus and tuberosity of the 5th
metatarsal are well visualized
• The navicular is partially superimposed over the
cuboid and the cuneiforms; metatarsals and phalan-
ges are superimposed
Lateral Foot (Lateromedial)
Positioning Criteria
• Patient is positioned lateral recumbent onto unaf-
fected side
• Flex knee and place medial portion of the foot in
contact with the IR
• Adjust the long axis of the foot in line with the long
axis of the IR and center the foot to the IR
• The plantar surface of the foot should be perpendicu-
lar to the IR
• Instruct the patient to slightly dorsiflex the foot if
possible
• Direct the central ray perpendicular to the midpor-
tion of the foot at the level of the base of the 3rd
metatarsal
• Collimate close to the anatomy to include the entire
foot and approximately 1⬙ (2.5 cm) of the distal tibia
Evaluation Criteria
• As compared to the mediolateral lateral projection of
the foot, this projection enables a more true lateral
view of the foot
• The entire foot from the superimposed phalanges to
the calcaneus is demonstrated
• The distal fibula is superimposed by the posterior
portion of the tibia, and the tibiotalar joint space
is open
Demonstrates
• The calcaneus and talus and tuberosity of the 5th
metatarsal are well visualized
• The navicular is partially superimposed over the
cuboid and the cuneiforms; metatarsals and phalan-
ges are superimposed
FIGURE 5-29
122
CHAPTER 5
|
IMAGING PROCEDURES
Anteroposterior Weight-Bearing Feet
Positioning Criteria
• Instruct the patient to stand on the IR and evenly dis-
tribute weight on both feet
• Adjust the feet so that they are pointing forward and
are centered to each half of the IR
• Central ray is directed 15 degrees posteriorly midway
between both feet to enter at the level of the base of
the metatarsals
• Collimate to include both feet in their entirety
Evaluation Criteria
• No rotation of the feet
• Bases of the 1st and 2nd metatarsals are free of su-
perimposition
• Bases of the 3rd to 5th metatarsals superimposed
• Open joint space between the 1st and 2nd cuneiforms
(medial and intermediate cuneiforms)
Demonstrates
• Both feet, including phalanges, metatarsals, and tarsals
• The presence of hallux valgus is best demonstrated
in this projection
Lateral Weight-Bearing Feet
Positioning Criteria
• Instruct the patient to stand on wood blocks or a spe-
cial positioning device designed for weight-bearing feet
• Ensure that the x-ray tube is able to be lowered enough
to be centered to the foot; otherwise, the platform that
the patient is standing on must be elevated
• Place the IR between the feet with the medial aspect
of the foot in contact with the IR
• Ensure that the foot is not rotated
• Lower the x-ray tube and direct the central ray hori-
zontally to the level of the base of the 3rd metatarsal
• Collimate to include the entire foot and ankle joint
• Turn the patient toward the opposite direction and
repeat for the other foot
Evaluation Criteria
• The foot is visualized in a lateral position with no
rotation
• The ankle joint is visualized
Demonstrates
• The entire foot is demonstrated from the phalanges
to the metatarsals
• Pes planus (flat feet) and pes cavus (high arches) are
demonstrated in the lateral projections
Sesamoid Bones (Lewis Method)
Positioning Criteria
• Position the patient prone and instruct the patient to
dorsiflex the foot and 1st toe, placing the 1st toe in
contact with the center of the IR
• Adjust the plantar surface of the foot so that it is
15 degrees to 20 degrees from vertical (calcaneus not
superimposed over metatarsal head)
• Ensure that there is no rotation of the foot
• Direct the central ray in tangent to the 1st metatarso-
phalangeal joint
• Collimate close to the anatomy to include the 1st to
2nd metatarsals
Evaluation Criteria
• No rotation of the foot
• Sesamoid bones visualized free of metatarsal super-
imposition
• Open space between the sesamoids and the metatarsals
Demonstrates
• Sesamoid bones visualized in tangent with minimal
magnification
Sesamoid Bones (Holly Method)
Positioning Criteria
• Position the patient supine or seated and instruct the
patient to slightly dorsiflex the foot and attain maxi-
mum dorsiflexion of the 1st toe
• Adjust the plantar surface of the foot so that it is
15 degrees to 20 degrees from vertical (calcaneus not
superimposed over metatarsal head)
• Gauze or strong tape may be used to assist in dor-
siflexion of the toes and to minimize patient motion
• Ensure that there is no rotation of the foot
• Direct the central ray in tangent to the 1st metatarso-
phalangeal joint
• Collimate close to the anatomy to include the 1st to
2nd metatarsals
Evaluation Criteria
• No rotation of the foot
• Sesamoid bones visualized free of metatarsal super-
imposition
• Open space between the sesamoids and the metatarsals
Demonstrates
• Sesamoid bones visualized in tangent with magnifica-
tion due to the increased OID
123
CHAPTER 5
|
IMAGING PROCEDURES
Demonstrates
• Distal one-third of the lower leg
• Lateral malleolus free of superimposition
• Talus
• Proximal portion of metatarsals
• Distal tibiofibular joint is open
Anteroposterior Mortise Ankle
Positioning Criteria
• Align ankle to midpoint of the IR
• Long axis of distal leg should run parallel with the IR
• Foot should remain in neutral position
• Rotate entire leg, ankle, and foot 15 degrees to
20 degrees internally
• Support may be used as needed to hold anatomy in place
• Central ray should be directed midway between malleoli
Evaluation Criteria
• Ankle joint should be centered to the IR
• The intermalleolar line should be parallel to the IR
• Four-sided collimation, with the distal one-third of tibia
and fibula, ankle joint, talus, and proximal metatarsals
• Soft tissue should be included
• Mortise should appear open
Anteroposterior Ankle
Positioning Criteria
• Dorsiflex foot in order to create a 90-degree angle
with the plantar portion of the foot and the distal leg
• Ensure toes are not superimposed over ankle
• Entire lower leg must be parallel with the longitudinal
axis of the IR
• Central ray directed perpendicular to midpoint of
malleoli
• Collimate to include distal one-third of tibia and fib-
ula proximally and the talus distally
Evaluation Criteria
• Distal tibia and fibula will be slightly superimposed
• Distal anterior view of tibia, fibula, lateral and
medial malleoli, tibiotalar joint, and talus should be
v isualized
• The navicular, cuboid, and cuneiforms will display
the shadow of the dorsiflexed foot, therefore will not
be optimally visualized
• Long axis of distal leg should run parallel with the IR
• Distal 5th metatarsal should be within the collimated
field because this area is a common site of fracture
• Collimation should be four sided, but open enough to
include the soft tissue of the ankle
Demonstrates
• AP view of ankle, talus, medial and lateral malleoli,
and distal one-third of tibia and fibula
• Talofibular articulation will not appear open; with
proper AP alignment, this is an indication there are
no ligament tears
• Normal overlapping of the tibiofibular articulation
and of the anterior tubercle over the distal fibula
Medial Anteroposterior Oblique Ankle
Positioning Criteria
• Dorsiflexion of foot remains
• Leg as well as foot should be rotated medially 45 degrees
• Support may be used as needed to hold anatomy in
place
• Central ray will remain midway between malleoli
Evaluation Criteria
• The tibiofibular articulation will be open
• The fibula will not superimpose over the talus
• The lateral subtalar joint is open slightly
• Distal tibia, fibula, and talus are demonstrated
• The base of the 5th metatarsal should be within the
collimated field because of frequency of fracture in
this area
FIGURE 5-30