Lower Extremity Flashcards
Why are the IP joint spaces not best shown on an AP projection of the toes?
Because of the natural curve of the toes
AP Axial Projection of the toes is recommended to
Open the joint spaces and reduce foreshortening
AP Axial Projection of Toes CR
Direct the central ray 15 degrees posteriorly through the third MTP joint
AP Oblique Projection (Medial Rotation) of Toes + CR
Medially rotate leg and adjust plantar surface of the foot to form a 30-45 degree angle
CR perpendicular entering third MTP joint
Lateral Projection (Great Toe)
Lateral recumbent position. Place patient on unaffected side and rotate foot until toe is in true lateral position (mediolateral)
AP or AP Axial Projection angle (Foot) + CR
Angle of 10 degrees posteriorly (toward heel) entering at the base of the 3rd metatarsal OR perpendicular to the IR
CR perpendicular to the metatarsals, reducing foreshortening
For Foot, what Projection is best to see the TMT joints?
AP or AP Axial
What is the AP/AP Axial Projection used for (Foot)
Localizing foreign bodies, fractures of the metatarsals and anterior tarsals
AP Oblique Projection (Medial Rotation) Foot
Center IR to midline of the foot at the level of the 3rd metatarsal. Rotate medially at an angle of 30 degrees. If rotated more, the lateral cuneiform will superimpose the others.
Which projection of the foot best demonstrates the cuboid and its articulations?
AP oblique (medial rotation)
How should the central ray be directed to best demonstrate the tarsometatarsal joint spaces of the midfoot for the AP projection of the foot?
10 degrees posteriorly (toward the heel)
Which projection of the foot best demonstrates the sinus tarsi?
AP oblique projection (medial rotation)
Which projection of the foot best demonstrates most of the tarsals with the least amount of superimposition
AP oblique projection (medial rotation)
Which projection of the foot best demonstrates the bases of the fourth and fifth metatarsals free from superimposition
AP oblique projection (medial rotation)
Which two projections comprise the typical series that best demonstrates the calcaneus
Axial (plantodorsal) and lateral projections
How many degrees and in what direction should the central ray be directed for the axial (plantodorsal) projection of the calcaneus
40 degrees cephalad
At which level on the plantar surface should the central ray enter the foot for the axial (plantodorsal projection of the calcaneus
Base of the third metatarsal
Where should the central ray be directed for the lateral projectio of the calcaneus
Toward the midpoint of the calcaneus
Where should the central ray enter for the lateral projections of the ankle
At the medial malleolus
How many degrees and in which direction should the foot and leg be rotated to best demonstrate the mortise joit for the AP oblique projection of the ankle
15 to 20 degrees medially
Which projection of the anke best demonstrates the talofibular joint space free from bony superimposition
AP oblique projection (medial rotation
With reference to the plane of the IR, how should the malleoli be positioned for the AP oblique projection of the ankle to best demonstrate the mortise joint space open
Parallel
Which projection of the knee best demonstrates the femorotibial joint spaces open if teh patient measures more than 10 inces between the ASIS and the tabletop
AP projection with the central ray angled 3 to 5 degrees cephalad
For the lateral projection of the knee, how many degrees should the knees be flexed
20 to 30 degrees
How many degrees of angulation should be formed between the femur and the radiographic table for the PA axial projection (Holmblad method) of the knee
70 degrees
Which of the following projections of the knee best demonstrates the intercondylar fossa
PA axial projection (Holmblad method
How many degrees and in what direction should the central ray be directed for the lateral projection of the knee
5 to 7 degrees cephalad
Which structure of the knee is best demonstrated with the tangential projection
Patella
Which structure of the knee is best demonstrated with the PA axial projection (the Holmblad method)
Femoral intercondylar fossa
Which projection of the knee best demonstrates the femoropatellar space open
Lateral
Which of the following evaluation criteria indicates that the knee is properly positioned for a lateral projection
The femoral condyles are superimposed
What should be done to prevent the knee joint space from being obscured by the magnified shadow of the medial femoral condyle when the lateral projection of the knee is performed
Direct the CR 5 to 7 degrees cephalad
For the lateral projection of the patella, which positioning maneuver reduces the femorpatellar joint space
Flexing the knee more than 10 degrees
Which area of the knee should the central ray enter for the PA axial projection (Holmblad method)?
Posterior
Which projection of the knee should be used to demonstrate the patella completely superimposed on the femur
AP
For which projection of the knee should the patient be prone on the table, with the knee flexed until the leg forms an angle of 40 degrees with the table, and the CR directed perpendicular to the long axis of the leg, entering the back side of the knee
PA axial projection (Camp-Coventry method
Which projection of the knee can be accomplishedwith the patient upright, the affected knee flexed and its anterior surface in contactwith a vertically placed IR, and the horizontally directed central ray entering the posterior aspect of the knee
PA axial projection (Holmblad method
Which positioning factor determines the number of degrees the central ray should be angled for the tangential proejction (Settegast method) to demonstrate the patella
Degree of knee flexion
How should the CR be directed for the AP projections of the femur
Perpendicular
Which positioning maneuver should be performed to place the femoral neck in profile for the AP projection of the proximal femur
Rotate the lower limb medially 10 to 15 degrees
For which lower limb projection should the lower limb be rotated medially 10 to 15 degrees
AP projection of the proximal femur
For which lower limb projection should the pelvis be rotated 10 to 15 degrees from true lateral
Lateral projection of the proximal femur
For the lateral projection of the femur, how should the pelvis be positioned to demonstrate only the knee joint with the distal femoral shaft
True Lateral
How many and what kind of bones comprise the foot and ankle?
14 phalanges, 5 metatarsals and 7 tarsals
Which bone classification are tarsals
Short
Which tarsal bone is located on the medial side of the foot between the talus and three cuneiforms
Navicular
Which articulation of the foot is a gliding-type joint
Intertarsal
Which two tarsal bones articulate with each other by way of three facets
Talus and calcaneus
Which part of the talus articulates with the distal tibia
Trochlea
Which type of joint is the ankle joint
Hinge
WHich joint is formed by the articulation of the head of the fibula with the lateral condyle of the tibia
Proximal tibiofibular
WHich type of joint is the proximal tibiofibular joint
Gliding
How and toward what centering poit should the central ray be directed forthe AP oblique projection to demonstrate all five toes
Perpendicular to the 3rd metatarsophalangeal joint
What other projection term refers to the AP projection of the foot
Dorsoplantar
How many degrees and in what direction should the foot be rotated for the AP oblique projection to best demonstrate the great toe
30 to 45
How many degrees and in what direction should the central ray be directed for the AP axial projection of the foot
10 degrees cephalad (towards the head)
How many degrees and in what direction should the foot be rotated for the AP oblique projection for the foot?
30 degrees medially
This is the second longest bone in the body and is situated on the medial side of the leg; it is also a weight-bearing bone
Tibia
Avulsion fracture of the base of the fifth metatarsal
Jones Fracture
For the lateral projection of the foot, dorsiflex the foot to form a _____ degree angle with the lower leg
90
What does the lateral projection, weight-bearing method show
It shows the structural status of the longitudinal arch
limb is rotated externally 45-degrees; demonstrates the margin of the patella projected slightly beyond the edge of the lateral femoral condyle
AP Oblique Projection (lateral rotation) of the Knee
What does the weight-bearing AP Projection that is routinely included in the radiographic examination show
Arthritic Knees, reveals narrowing of the joint space that appears normal on a non-weight-bearing study
What does the Holmblad method show
Shows the intercondylar fossa
What is the flexion of the knee in the PA axial projection (Holmblad Method
70 degrees from full extension (20-degree difference from the central ray
What projection should not be attempted until a transverse fracture of the patella has been ruled out
Settagast (sunrise)
Inferiosuperior flexion and Cr angle knee to see patella and patellofemoral joint
CR 10-15 degrees and knees flexed 40-45
Settagast (sunrise) CR and flexion of knees
CR 15-20 and knees flexed 90
Hughston method knee Cr and flexion
Cr 15-20 and knee flexed 40
Rosenberg Method (pa Axial weight bearing knee bilateral)
Knees flexed 45 degrees CR 30