1. Lower Limb

2. Evaluation Criteria Structures shown Position/projection
Collimation/central ray
Exposure criteria
Acceptable and unacceptable images of the lower limb based on errors i.e.:
Motion
Collimation
Positioning
Exposure factors
Side markers and patient demographic information
Every time a radiographer completes an image, an evaluation must be made to determine whether the image is diagnostically optimal for the radiologist to provide an accurate diagnosis. A radiologist should NEVER have to return an image for repeat if proper evaluation of the image is done by the radiographer.
Here are five basic criteria for radiographic evaluations and critique. These should be used every time a radiographic image is performed.

3. Introduction <Image 1>
This anatomic study of the lower limb and the pelvis is divided into five major regions: foot, ankle joint, lower leg, knee joint, femur. The primary functions of the bony anatomic structures of the lower limb and pelvis are to provide weight-bearing support for the rest of the body and to enable the body to move during walking, running and other activities.

4. Toes Positioning Basics
<Images #2, 3,4>
The most common reason for imaging the toe(s) is trauma. Structures demonstration the AP, oblique and lateral imaging positions/projections include the phalanges, the interphalangeal joints, and the distal ends of the metatarsals. The metatarsophalangeal joints are not well visualized on the AP projection. The criteria presented for toes is the same for each toe. Routine projections include the AP, AP medial oblique, and lateral of affected toe.

5. Toes Imaging Criteria
Technical Considerations
Detail IR
Non-grid (table top)
kVp range: 55-60
SID: 40 inches (100 cm)
IR size 8x10 inch (18x24 cm) or 10x 12 inch (25X30 cm)
Patient Position
AP, AP medial oblique, lateral of affected toe
Patient is seated on the table with knee flexed
All potential artifacts, including shoes and sock, removed from the part
Part Position
AP toes:
Place the foot flat on the IR with the toes centered to the unexposed portion of the IR
AP medial oblique toes:
Rotate the foot internally (medially) 30 degrees
Lateral toes:
Patient is in the lateral recumbent position
Center the toes to the unexposed portion of the IR
Rest the foot on the medial surface for toes one, two and three
Rest the foot on the lateral surface for toes four and five
Use a strip of gauze to gently pull the affected toe forward or backward from the other toes to prevent superimposition
Central Ray (CR)
CR is perpendicular to the 2nd metatarsophalangeal joint
CR is perpendicular to the 3rd metatarsophalangeal joint
CR for toe #1, perpendicular to the interphalangeal joint
CR for toes #2, 3, 4, 5, perpendicular to the proximal interphalangeal joint of the affected toe
Patient Instructions
“Breathe normally and don’t move.”
Evaluation Criteria
Phalanges should not be rotated
Toes should be slightly separated
Distal ends of the metatarsals should be included
All phalanges of the digit should be seen on the image
Obliquity of the toes should be evident
Interphalangeal and second through fifth metatarsophalangeal joint spaces should be open
First metatarsophalangeal joint space is not always open
Phalanx of interest should be seen in profile and without superimposition of the other toes
When complete separation is not possible, the proximal phalanx should be visualized through the superimposed structures
Interphalangeal and metarsophalangeal joint spaces should be open.
Additional Information
To open joint spaces, angle CR 15 degrees posteriorly
Many department protocols require that on the initial image
Some department protocols require the entire foot to be demonstrated on the AP projection
This can be accomplished on half of a 10x12 inch (25x30 cm) IR with the oblique and lateral of only one toe on the other half of the IR
Some departmental protocols call for a 45 degree medial oblique of the foot and toes
Click each button for more information about imaging the toes.
Technical Considerations
Evaluation Criteria
Additional Information

6. Knowledge Check At what point does the CR enter on the AP toes?
1st metatarsal phalangeal joint
2nd metatarsal phalangeal joint
3rd metatarsal phalangeal joint
1st distal phalangeal joint

7. Foot Basics <Images 8, 9, 10>
The most common reasons for imaging the foot are trauma and other anomalies of the bones of the foot. The routine positions/projections of the foot are the AP axial (dorsoplantar), AP medial oblique and lateral. These images of the foot provide a general survey of the bones of the foot, including the phalanges, the metatarsals and the tarsals including the talus and calcaneus.

8. Foot Imaging Criteria Click each button for more information about XYZ
Technical Considerations
Detail IR
Non-grid (table top)
kVp range: 55-60
SID: 40 inches (100 cm)
IR size 10x 12 inch (24X30 cm)
Patient Position
AP axial (dorsoplantar), AP medial oblique, lateral foot
Patient is seated on the table with knee flexed
All potential artifacts, including shoes and sock, removed from the part
Part Position
AP axial (dorsoplantar):
Place the foot flat on the IR centered to the unexposed portion of the IR
AP medial oblique foot:
Rotate the foot internally (medially) 30 degrees
Lateral foot:
Patient is in the lateral recumbent position on the affected side with the unaffected leg behind the affected leg
Remove all potential artifacts, including shoe and sock
Rest the foot lateral surface on the IR
Dorsiflex the foot
Adjust the foot so the plantar surface is perpendicular to the IR
Central Ray (CR)
AP Foot:
CR is perpendicular to the base of the 3rd metatarsal
Or a 10 degree angle to the base of the 3rd metatarsal
CR perpendicular to the middle of the foot
Patient Instructions
“Breathe normally and don’t move.”
Evaluation Criteria
AP foot:
Foot should not be rotated as evidenced by equal space between mid-shafts of adjacent metatarsals (2-4) and overlap of bases of second, third, and fourth metatarsals.
Third to fifth metatarsal bases should be free of superimposition
Bases of the first and second metatarsals should be superimposed
Sinus tarsi should be visualized
Tuberosity of the fifth metatarsal should be visualized
Equal amount of space should exist between shafts of the second through fifth metatarsals
Metatarsals should be nearly superimposed on each other
The distal tibia and fibula with the fibula slightly overlapping the posterior tibia
Tibiotalar joint should be visualized
Additional Information
Using a 10 degree CR angulation demonstrates more open metatarsophalangeal joints
Using a compensating filter is helpful in achieving consistent density throughout the foot
Foot can be rotated laterally 30 degrees to better demonstrate the interspace between the first and second metatarsals and between the medial and intermediate cuneiform.
Placing a support under the knee may be helpful in maintaining the foot in a true lateral position
If the patient conditions permits, the patient may be placed in the lateral recumbent position on the unaffected side
The foot should rest on the medial surface (lateromedial) and the foot adjusted so the plantar surface is perpendicular to the IR. This provides a truer lateral view of the foot, ankle joint, and distal tibia and fibula.
Click each button for more information about XYZ
Technical Considerations
Evaluation Criteria
Additional Information

9. Knowledge Check What are the routine positions for a foot series?
PA, lateral, lateral oblique
AP dorsoplantar, lateral
AP dorsoplantar, lateral, medial oblique
AP, plantar dorsal, medial oblique

10. Ankle Basics <Images 11, 12, 13>
There are three basic routine positions of the ankle: AP, AP medial oblique and lateral. The most common reasons for ankle imaging are trauma and bone anomalies. Structures demonstrated on the ankle images include distal tibia and fibula and the proximal portion of the talus, tibiotalar joint, ankle joint and proximal tarsals. Facility protocol may be for the degree medial oblique, often called the “mortise view” or the 45 degree medial oblique of the ankle. The images shown here demonstrate the ankle from 0 degrees rotation to 45 degrees rotation and the anatomy of the ankle shown at the various degrees of rotation.

11. Ankle Criteria
Technical Considerations
Detail IR
Non-grid (table top)
kVp range: 55-60
SID: 40 inches (100 cm)
IR size 10x 12 inch (24X30 cm)
Patient Position
AP, AP medial oblique, lateral
Patient is seated on the table with knee extended
All potential artifacts, including shoes and sock, removed from the part
Part Position
AP ankle:
Dorsiflex the foot so its plantar surface is perpendicular to the IR
Center the ankle to the unexposed portion of the IR
Adjust the foot so the ankle is in a true AP position (intermalleolar plane WILL NOT be parallel with the IR surface
AP medial oblique ankle:
Adjust the long axis of the ankle parallel with the long axis of the IR
Rotate the entire leg and foot 45 degrees
Dorsiflex the foot to place the plantar surface perpendicular to the IR
Lateral ankle:
Rest the lateral surface of the foot and ankle on the IR
Adjust so the long axis of the leg is parallel with the longitudinal axis of the IR
Center the ankle to the IR
Dorsiflex the foot to a right angle and adjust so the plantar surface is perpendicular to the IR
Place the intermalleolar plane perpendicular to the IR
Central Ray (CR)
CR is perpendicular midway between the malleoli
Lateral foot:
CR perpendicular to the medial malleous
Patient Instructions
“Breathe normally and don’t move.”
Evaluation Criteria
Visualization of both the lateral and medial malleoli with moderate overlapping at the distal tibiofibular articulation
Visualization of the tibiotalar joint space with the medial tibiotalar articulation free of overlap
Distal tibia and fibula should not be overlapped
Fibula should be projected over the posterior tibia
Tibiotalar joint must be well visualized with medial and lateral talar domes superimposed
Additional Information
AP ankle and AP medial oblique ankle:
To visualize more of the tibia and fibula position the ankle closer to the lower edge of the IR
If the ankle joint is involved, CR should be directed through the ankle joint to prevent distortion of the joint space
Placing a support under the knee may be helpful in maintaining the foot in a true lateral position
If patient conditions permit, the patient may be placed in the lateral recumbent position on the unaffected side
The foot should rest on the medial surface (lateromedial) and the foot adjusted so the plantar surface is perpendicular to the IR. This provides a truer lateral view of the foot, ankle joint, and distal tibia and fibula
To visualize more of the tibia and fibula position the ankle closer to the lower edge of the IR. This provides a truer lateral view of the foot, ankle joint, and distal tibia and fibula.
Click each button for more information about imaging the ankle.
Technical Considerations
Evaluation Criteria
Additional Information

12. Knowledge Check <Images 20, 19> Label the following anatomy:
Fibula
Tibia
Fibular notch
Lateral malleolus
Malleolar fossa
Inferior articular surface
Ankle joint
Talus
Trochlea of the talus
Articular facet
Body of the talus
Talocalcaneal joint
Navicular
Medial cuneiform

13. Tibia and Fibula Basics
<Images 21 and 22>
The most common indication for imaging of the lower leg (tibia and fibula) is trauma. Structures demonstrated on the radiograph include the tibia, fibula, and adjacent joints. Routine projects include the AP and lateral lower leg.

14. Tibia and Fibula Imaging Criteria
Technical Considerations
Detail IR
Non-grid (table top)
kVp range: 55-60
SID: 40 inches (100 cm)
IR size 14x17 inch (36 x43 cm)
Patient Position
AP and lateral
Patient is seated on the table with knee extended
All potential artifacts, including shoes and sock, removed from the part
Part Position
AP :
Dorsiflex the foot so its plantar surface is perpendicular to the IR
Center the leg the IR
Lateral :
Rest the lateral surface of the foot and ankle on the IR
Adjust so the long axis of the leg is parallel with the longitudinal axis of the IR
Center the leg to the IR
Dorsiflex the foot to a right angle and adjust so the plantar surface is perpendicular to the IR
Adjust the rotation of the leg so the patella is perpendicular to the IR
Central Ray (CR)
AP and Lateral:
CR is perpendicular to midpoint of the leg
Patient Instructions
“Breathe normally and don’t move.”
Evaluation Criteria
Both the knee and ankle joints should be included
If necessary perform a separate AP of one joint when both joints are not included on the image
Knee and ankle joints should be in true AP position
Tibia and fibula should be slightly overlapped at both the proximal and distal ends
Lateral:
There should be slight separation of the shafts of the tibia and fibula except at the proximal and distal ends
Proximally, there will be some overlap of the fibula and tibia
Distally, the fibula should overlap the posterior tibia
Additional Information:
AP:
It may be necessary to invert the foot slightly to adjust the leg into the true AP position, but care must be taken to NOT rotate the entire leg
It is important, on the initial imaging, to include both joints
Some departmental protocols may permit follow-up imaging to include only the joint nearest the site of injury
If the leg is too long to include both joints, it may be positioned diagonally on a 14 x 17 inch (36 x 43 cm) IR for each position of the leg
If the patient condition does not permit turning the patient, a cross-table projection may be performed
Affected leg should be carefully lifted so that a firm support can be placed beneath it
The IR is placed on the medial surface of the leg and the CR directed from the lateral side
Both joints must be included on the initial imaging
The IR can be turned diagonally on a 14 x 17 inch (36 x 43 cm) to include both joints
Click each button for more information about imaging the tibia and fibula.
Technical Considerations
Evaluation Criteria
Additional Information

15. Knowledge Check
What is the positioning error if the tibia and fibula are superimposed on the lateral position?
Lateral over-rotation
Not enough lateral rotation
This is not a positioning error

16. Knee Basics <Images #27, 30, 31>
Radiographic imaging of the knee is performed because of trauma or degenerative joint disease. Structures demonstrated include the knee joint, the proximal tibia and fibula, and the distal femur. The routine positions/projections include AP or PA, patellar view, and Lateral. Obliques of the knee are performed but not usually as part of the routine series.

17. Knee Imaging Criteria
Technical Considerations
Regular IR
Grid
kVp range:
SID: 40 inches (100 cm)
IR size 10 x 12 inch (24 x 30 cm)
Patient Position
AP and lateral
Patient is seated on the table with knee extended
All potential artifacts, including shoes and sock, removed from the part
Patella:
Prone on the table with the knee flexed
All potential artifacts, from the distal femur down removed
Part Position
AP :
Center the knee joint ( ½ inch distal to the patellar apex) to the midline of the table and adjust the knee so the interepicondylar plane is parallel to the surface of the IR
Patella will lie slightly to the medial side of the knee
Lateral :
Rest the knee on its lateral surface and center it to the midline of the table
Flex the knee 20 to 30 degrees
Adjust the knee so the interepicondylar plane is perpendicular to the IR
Center the patella 2 to 3 inches from the lower edge of the IR
Slowly flex the knee until the patella is perpendicular to the IR (approximately 100 degrees)
Central Ray (CR)
AP:
CR one half inch (1 cm) distal to the patellar apex with a 5 degree cephalic angle
Lateral:
5 degree cephalic angle to the knee joint (1/2 inch (1 cm) distal to the patellar apex
Perpendicular to the space between the patella and the femoral condyles
Degree of angulation will depend on the degree of flexion of the knee
Patient Instructions
“Breathe normally and don’t move.”
Evaluation Criteria
Femur and tibia should be seen without rotation
Femorotibial joint space should be open
Head of the fibula will be slightly overlapped by the proximal tibia
Patella should be completely superimposed over the femur
In the normal knee, the femorotibial joint space should be equal on both the medial and lateral sides
Femoral condyles should be superimposed
Patella should be projected in profile
Femoropatellar space should be open
Fibular head and the tibia should be slightly superimposed
Patellofemoral interspace should be open
Patella should be seen in profile
Femoral condyles should be visualized
Additional Information:
It may be necessary to invert the foot slightly to adjust the leg into the true AP position, but care must be taken to NOT rotate the entire leg
Non-grid method may be used for a knee that measures less than 11 cm
When the primary interest is the distal femur or the proximal tibia and fibula, the CR may be directed perpendicular through the knee joint
In cases where the patient is unable to fully extend the knee, a curved IR is recommended to reduce the part to image receptor distance
A support placed under the heel/ankle of the affected leg helps in maintaining the knee in the true lateral position
Non-grid method may be used for a knee that measures less then 11 cm
In cases of patella fracture, the knee should be flexed no more than 15 degrees
A gauze strip may be looped around the ankle and used to achieve/maintain the necessary flexion
It is possible to obtain a similar image with the patient in the supine, seated, or lateral position as long as the same part-IR and tube-IR relationships are maintained.
Click each button for more information about imaging the knee.
Technical Considerations
Evaluation Criteria
Additional Information

18. Knowledge Check
What is the rational for performing weight bearing bilateral AP knee imaging?
Trauma,
Better femur images
Degenerative joint disease
D. Better image of the patella

19. Femur Basics < Images 39, 40>
As with most bone imaging, the most common rationale for imaging the femur is trauma. Sometimes there may be tumors of the femur but this is rare. Structures demonstrated on the AP and lateral femur images include the entire length of the femur and the knee or hip joint or both. Routine positions/projections include the AP and lateral.

20. Femur Imaging Criteria
Technical Considerations
Regular IR
Grid
kVp range: 60 to 75
SID: 40 inches (100 cm)
IR size 14 x 17 inch (35 x45)
Patient Position
AP and Lateral
Patient is supine on the table with the knee extended
Patient should be in a gown with all clothing from waist down removed
Part Position
AP :
Center the thigh to the midline of the table and position it to include both joints when possible
If not possible to get both joints the joint nearest to the site of injury or suspected pathology
Adjust the femur in to the AP position with the interepicondylar plane parallel to the IR
Internally rotate the foot approximately 15 degrees
Lateral :
Flex the knee and center the thigh to the midline of the table and position it to include both joints when possible
If it is not possible to get both joints on the image the joint nearest the site of injury or suspected pathology
Adjust the femur into the lateral position with the interepicondylar plane perpendicular to the IR
Central Ray (CR)
AP and Lateral:
CR Perpendicular to the mid point of the femur
Patient Instructions
“Take in a breath and hold it, don’t breathe or move.”
Evaluation Criteria
Either the knee or hip joint (the one closest to the injury or suspected pathology) should be included on the image
A separate AP of the other joint may be indicated
Little or none of the lesser trochanter should be visible beyond the medial edge of the femur
Any orthopedic appliance (e.g., surgical plate) should be seen in its entirety
Lateral:
The same joints included on the AP should also be included on the lateral
A separate lateral of one joint may be indicated
When the knee is included, it should meet the criteria identified in evaluating a lateral knee
When the hip is included, the thigh of the unaffected leg should not overlap the area of interest
Additional Information:
AP:
AEC should not be used when an orthopedic appliance is in place
The regular lateral position should not be used when a fracture is suspected
Because of the possibility of displacing fragments the patient is not to be moved
A translateral (cross-table) should be done instead
Do not use the AEC when imaging a femur with an orthopedic appliance in place
Click each button for more information about imaging the femur
Technical Considerations
Evaluation Criteria
Additional Information

21. Knowledge Check <Images #40, 43> Label the following anatomy:
Acetabulum
Greater trochanter
Femoral neck
Lesser trochanter
Femoral shaft

22. Summary
There many positions/projections of the lower limb that demonstrate various anatomy. When the radiographer has become proficient with the routine positions/projections the alternate positions/projection are easier.