chapter 6

a lateral ankle projection demonstrates the fibula too anterior to the tibia, and a narrowed talocalcaneal joint. how are the talar domes positioned on this projection

-lateral dome anterior -lateral dome proximal

an AP 1st toe projection that was obtained with the foot and the toe rotated 45* medially demonstrates

-more midshaft concavity on one side of the phalanges than on the opposite side -twice as much soft tissue on one side of the phalanges as on the opposite side

if the patient is unable to dorsiflex the foot to a vertical position for an axial calcaneus projection, the

image will demonstrate a foreshortened calcaneal tuberosiy unless the central ray angle is increased over the routinely required angulation

a less than optimal PA axial knee projection (Holmblad method) demonstrating the medial and lateral aspects of the intercondylar fossa without superimposition

was obtained because the femur was positioned vertically

a less than optimal lateral foot projection demonstrating the lateral talar dome proximal to the medial talar dome

was obtained with the proximal lower leg elevated

for a tangential knee projection (Merchant method)

-an imaginary line connecting the femoral epicondyles is aligned parallel with the imaging table. -the patient is instructed to relax the leg muscles

for an AP projection of the knee with accurate positioning

-an imaginary line connecting the femoral epicondyles is aligned parallel with the IR -the intercondyler eminence is centered within the intercondyler fossa -the fibular head is demonstrated about 0.5" distal to the tibial plateau -the femoral condyles are symmetrical

a lateral 4th toe projection, the

-foot is rotated laterally until the toe is in a lateral position -adjacent toes are drawn away from the affected toe -central ray is centered to the PIP joint

an axial calcaneus projection with the patients foot in a plantar flexion and the central ray angled 40* proximally demonstrates a(n)

-foreshortened calcaneal tuberosity -closed talocaneal joint space

an AP oblique foot projection with accurate positioning demonstrates

-open joint spaces around the cuboid -the long axis of the foot aligned with the long axis of the collimated field

the placement of the patella in relationship to the femorotibial joint space on an AP knee projection is affected by

-patellar subluxation. -knee flexion.

a lateral knee projection with accurate positioning demonstrates

-superimposed femoral condyles -an open femorotibial joint space -1/4 of the distal femur and proximal lower leg

proper elevation of the distal lower leg and vertical placement of the foots long axis (heel is not rotated side to side) for the PA axial knee projection (Holmblad method)

-superimposes the lateral and the medial surfaces of the intercondylar fossa -superimposes the anterior and the posterior margins of the tibial plateau

positioning the femur at a 60-70* angle with the imaging table for the PA axial knee projection (Holmblad method)

-superimposes the proximal surfaces of the intercondylar fossa -places the patellar apex superior to the intercondylar fossa

a lateral knee projection demonstrates the medial femoral condyle anterior and proximal to the lateral femoral condyle. how was the positioning setup mispositioned for such an image to be obtained

-the central ray was angled too cephalically -the patients patella was positioned too close to the IR

if a PA axial knee projection (Hlmblad method) is obtained with the patients heel rotated internally (medially), which of the following are true

-the lateral and the medial surfaces of the intercondylar fossa are not superimposed -the patella is rotated laterally

a 15-20* internally rotated AP oblique ankle projection with accurate positioning demonstrates which of the following joints as open spaces

-tibiotalar -talofibular -lateral mortise -medial mortise

a 5-7* central ray angulation is used for a lateral knee projectoin

-to project the medial condyle anterosuperiorly -to offset the reduction in medial inclination that occurs when the patient is in a lateral recumbent position -to achieve an open femorotibial joint space

which aspect of the foot is placed parallel with the IR for a routine lateral foot projection

lateral

an externally rotated AP oblique knee projection that was taken with the knee rotated more than 45* will demonstrate the

lateral condyle in profile

why should the foot be dorsiflexed to a 90* angle with the lower leg for a lateral ankle projection

places the tibiotalar joint in a neutral position, more clearly defines the medial longitudinal arch, and prevents foot rotation.

the tangential knee projection (Merchant method) can also be described as a(n)______projection

superoinferior

a less than optimal lateral knee projection that demonstrates the medial femoral condyle anterior to the lateral femoral condyle will also demonstrate

the abductor tubercle on the anterior femoral condyle

an optimal AP axial foot projection demonstrates all of the following EXCEPT

the calcaneus without talar superimposition

an accurately positioned lateral foot projection demonstrates all of the following EXCEPT

the distal metatarsales a the center of the exposure field

an accurately positioned lateral foot projection demonstrates all of the following EXCEPT

the distal metatarsals at the center of the exposure field

an AP knee projection on a patient with an ASIS to table top measurement of 17cm was obtained using a perpendicular central ray, the resulting image will demonstrate

the fibular head more than 0.5" from the tibial plateau

if the patient is unable to extend the knee fully, an open femorotibial joint is accomplished by aligning the central ray perpendicular to the anterior surface of the lower leg and then

then decreasing the angle 3 to 5 degrees and centering to the femorotibial joint

an AP knee projection obtained with the knee internally rotated demonstrates

-a larger appearing lateral femoral condyle than medial condyle -the fibular head with decreased tibial superimposition

which of the following pertains to the positioning setup for an AP oblique foot projection on a patient with a high longitudinal arch

- Rotate the patient's foot 60 degrees. -Align the long axis of the foot with the long axis of the collimated field. -Center the central ray to the third metatarsal base.

for a lateral knee projection

- a patient with long femora and a narrow pelvis does not require an angled central ray. - a grid is used if the knee measures over 10 cm. -the central ray is centered 1 inch (2.5 cm) distal to the medial femoral epicondyles.

for an externally rotated AP oblique projection with accurate positioning, the

- fibular head, neck, and shaft are superimposed by the tibia. -medial condyle is shown in profile.

a cephalic central ray angulation is required on an AP knee projection when the

- patient's anterior tibial margin is demonstrated distal to the posterior tibial margin on the resulting image. - the knee is flexed and a curved IR is used.

what joint spaces are open on an AP oblique foot projection with accurate positioning

-2nd through 5th intermetatarsal joints -joint spaces surrounding the cuboid

when the legs are flexed 30* for the tangential knee projection (Merchant method), the central ray should be angled

75*

which of the following statements is true about an optimal tangential knee projection (Merchant method)

The lateral femoral condyle demonstrates more height than the medial femoral condyle

if the medial talar dome were positioned distal to the lateral talar dome on the lateral foot projection, which of the following is true

The patient's proximal tibia was elevated.

where should the central ray be centered for an AP axial projection of the foot

base of the 3rd metatarsal

a poorly positioned 45* AP oblique ankle projection demonstrates the calcaneus obscuring the distal aspect of the lateral mortise and the distal fibula. how should the positioning setup be adjusted to obtain an optimal projection

dorsiflex the foot to a 90* angle with the lower leg