Chapter 7 lower extremity
A. to what level on the patient should the upper border of an IR or collimated field be placed when demonstrating the proximal femur B. to what level of the patient should the lower border of the IR or collimated field be placed when demonstrating the distal femur?
(a) At the level of the ASIS (b) 2 inches below the knee
Concerning the placement of the unaffected (uppermost) limb, for femur (a) where should it be placed when demonstrating the proximal femur (b) Where should it be placed when demonstrating the distal femur
(a) posterior to the affected thigh (b) anterior of the affected thigh
A patient presents in the Emergency Department for lower leg radiographs after injuring the distal tibia. The patient has very long legs and it is impossible to fit the entire leg on the image receptor (IR). Which of the following would be the best radiographs to take for this patient? - Anteroposterior (AP) and lateral tibia/fibula making sure to include the ankle - Anteroposterior (AP) and lateral tibia/fibula to include the knee - Anteroposterior (AP) and lateral tibia/fibula to include the ankle, AP and lateral knee - Anteroposterior (AP) and lateral tibia/fibula to include the knee, AP and lateral ankle
- Anteroposterior (AP) and lateral tibia/fibula to include the ankle, AP and lateral knee -both joints need to be shown. leg radiographed so that the image includes the joint closest to injury, then separate images of the opposite joint should be obtained
Which view of the ankle is taken routinely when potential trauma or sprains of the ankle joint are involved to assess the structural integrity of the ankle? - Anteroposterior (AP) - Anteroposterior (AP) mortise - 45 degree oblique - Lateral
- Anteroposterior (AP) mortise
Which of the following statements regarding the femur is accurate? -Intercondylar fossa is found between the femoral epicondyles - Femoral neck is distal to the lesser trochanter - Popliteal surface is distal and anterior - Femoral shaft slants medially 5 - 15 degrees
- Femoral shaft slants medially 5 - 15 degrees this degree of slant is generally greater in women due to the width of the pelvis
How should the foot be positioned to demonstrate the ankle mortise? - Laterally rotated 30 degrees - Medially rotated 15 degrees - Medially rotated 45 degrees - Laterally rotated 10 degrees
- Medially rotated 15 degrees The ankle mortise refers to the joint space surrounding the superior and lateral borders of the talus and its articulations with the distal tibia and fibula. An open mortise can be visualized by rotating the foot medially approximately 15 degrees so that a plane through the medial and lateral malleoli is parallel with the IR.
Which two of the following statements are accurate regarding lateral ankle radiographs? (Select two) - Patient will lie on the unaffected side - Plantar surface of the foot is perpendicular to the image receptor (IR) - Dorsiflex the foot - Central ray is directed midway between the malleoli
- Plantar surface of the foot is perpendicular to the image receptor (IR) - Dorsiflex the foot To position the patient for a lateral ankle image, the patient should be laying in the affected side with the ankle joint centered to the IR. The foot should be dorsiflexed and the plantar surface of the foot adjusted to be perpendicular to the IR. The central ray should be perpendicular through the ankle joint, entering 1/2 inch (1.3 cm) superior to the lateral malleolus. The lateral malleolus will lie slightly posterior to the medial malleolus.
What is the rationale for angulation of the central ray when performing an anteroposterior (AP) foot radiograph? -Open the subtalar joint - Reduce foreshortening of the metatarsals -Visualize the sinus tarsi - Overcome superimposition of the sesamoid bones
- Reduce foreshortening of the metatarsals Angulation of the beam is performed to place the central ray perpendicular to the metatarsal bones and reduce foreshortening.
When evaluating an anteroposterior (AP) proximal femur radiograph the technologist observes the following: The bony trabecular detail is seen, collimation includes all soft tissue detail, the acetabulum is visible, and the lesser trochanter is visible without superimposition. What can the technologist conclude about this radiograph? - The image should be repeated because the leg was not internally rotated appropriately -The image should be repeated because there was not adequate collimation - The image should be repeated because the acetabulum should not be seen on this radiograph - The image is acceptable, no further action is needed
- The image should be repeated because the leg was not internally rotated appropriately To place the femur in the correct position and prevent foreshortening of the femoral neck, the leg must be internally rotated 10 to 15 degrees. This degree of rotation will cause the greater trochanter to be in profile.
Which two of the following bones articulate(s) with the cuboid? (Select two) -5th metatarsal -Medial cuneiform - Calcaneus -2nd metatarsal
-5th metatarsal -Calcaneus
Which two projections comprise the typical series that best demonstrates the calcaneus?
-Axial (plantodorsal) - lateral projections
Which three joint spaces should appear open to demonstrate no rotation on a lateral view of the calcaneus? (Select three) - Talonavicular joint -Talocalcaneal joint - Calcaneocuboid joint -Tibiotalar joint
-Calcaneocuboid joint -Tibiotalar joint -talonavicular The talonavicular, tibiotalar, and calcaneocuboid joint should appear open to demonstrate no rotation on a lateral view of the calcaneus. Other evidence would be superimposed superior portions of the talus and the lateral malleolus superimposed over the posterior half of the tibia and talus.
What anatomy should be demonstrated superiorly on a lateral view of the calcaneus? -Talus and distal tibia-fibula - Navicular and open joint space of the calcaneus and cuboid - Base of the 5th metatarsal and talonavicular joint - Tarsal sinus and calcaneocuboid joint space
-Talus and distal tibia-fibula -navicular is distally
Which two of the following statements are accurate regarding a lateral proximal femur image? (Select two) -The femoral head and acetabulum are included - The lesser trochanter is in profile medially - The greater trochanter is in profile laterally - The top of the image receptor (IR) should be approximately 1 inch superior to the anterior superior iliac spine (ASIS)
-The femoral head and acetabulum are included - The lesser trochanter is in profile medially top of IR should be at level of ASIS and entire hip joint indicated proximally. the greater trochanter is typically only partially visible and superimposed over the femoral neck. lesser should be in profile mon medial border of femur
How should the image receptor (IR) be placed when performing an anteroposterior (AP) proximal femur radiograph? - Center of the IR at the hip joint - Center of the IR 2 inches inferior to the anterior superior iliac spine (ASIS) • -Top of the IR at the level of the anterior superior iliac spine (ASIS) - Bottom of the IR at the apex of the patella
-Top of the IR at the level of the anterior superior iliac spine (ASIS); if can get the whole femur in one image then centering would be mid femur
lateral calcaneus collimation, CR, evaluation
-collimation: 1 inch beyond the posterior and inferior shadow of the heel. include medial malleolus and base of 5th metatarsal -CR: perp to calcaneus center about 1 inch distal to the medial malleolus (places it at the subtalar joint) -in lateral foot position -breaks happen from jumping and falling on them evaluation- -entire calcaneus, including ankle joint and adjacent tarsals -no rotation of calcaneus -tuberosity in profile -sinus tarsi open -calcaneocuboid and talonavicualr joints open
lateral foot evaluation criteria
-entire foot and distal leg -superimposed plantar surfaces of the metatarsal heads -fibula overlapping the posterior portion of the tibia -tibiotalar joint
AP projection femur evaluation
-femoral neck not foreshortened on prox femur -lesser trochanter not seen beyond the medial border of the femur or only a very small portion seen on proximal femur -no knee rotation on distal femur -any orthopedic appliance in its entirety
-what is the classification of the distal tibiofibular joint? -what is the condition described as an avulsion fracture of the tibial tuberosity?
-fibrous -osgood-schlatter
what composes a trimalleolar fracture?
-fractured lateral and medial malleolus and fractured posterior tibia
lateral knee evaluation:
-knee flexed 20-30 degrees in true lateral position (as demonstrated by femoral condyles superimposed) -the anterior surface of the medial condyle closer to the patella results from over-rotation toward the IR -the inferior surface of the medial condyle caudal to lateral condyle results from insufficient cephalad central ray angle -the inferior surface of lateral condyle caudal to medial condyle results from too much cephalad CR angle -fibular head and tibia slightly superimposed --overrotation- less superimposed -- under-rotated - more superimposed -open patellofemoral joint space -open joint space between femoral condyles and tibia
AP knee evaluation
-knee fully extended (if patient can) -entire knee without rotation -- femoral condyles symmetric and tibia intercondylar eminence centered -- slight superimposition of the fibular head if the tibia is normal -- patella completely superimposed on the femur -- open femorotibial joint space, with interspaces of equal width on both sides if the knee is normal
Lateral foot
-lie down turn toward affected side -medial surface of foot parallel with IR -plantar surface perp to IR -dorsiflex the foot to form a 90 degree angle with lower leg// pointing toes up CR: perp to base of third metatarsal
what are the proper positioning guideline for AP axial (beclere) knee radiograph -seated with body rotated 15 degrees -prone with body rotated 10 degrees -supine with no body rotation -supine with the body rotated 5 degrees
-supine with no body rotation
what articulations form the ankle mortise joint?
-talotibial -talofibular
In a settegast view what will be demonstrated?
-tangential patella -patellofemoral articulation
in the lateral projection of the ankle the: -tibia and fibula are superimposed -talotibial joint is visualized -talofibular joint is visualized
-tibia and fibula are superimposed -talotibial joint is visualized
in a lateral projection of the foot: -plantar surface should be perpendicular to the IR -metatarsals are superimposed -talofibular joints should be well visualized -tibiotalar joint should be visualized
-tibiotalar joint should be visualized -plantar surface should be perpendicular to the IR -metatarsals are superimposed
How many degrees and in what direction should the central ray be directed for the AP axial projection of the toes?
15 degrees cephalad (twoard the heel)
To demonstrate the ankle mortise, the leg and foot should be rotated medially how many degrees?
15-20
For the lateral projection of the knee, how many degrees should the knees be flexed?
20-30 degrees
how many bones are in the foot?
24
to what degree should the patient's foot be rotated for a medial oblique foot radiograph?
30
How many degrees and in what direction should the foot be rotated for the AP oblique projection for the foot?
30 degrees medially
what is the correct degree obliquity for an oblique image of the foot?
30 degrees; will demonstrate the articular spaces surrounding the cuboid without too much superimposition of metatarsal bones
How many degrees and in what direction should the foot be rotated for the AP oblique projection to demonstrate the second toe?
30 to 45 degrees medially
How many degrees and in which direction should the central ray be directed for the axial (plantodorsal) projection? (CALCANEUS)
40 degrees cephalad
for AP axial (beclere) knee the affected knee should be flexed to place the femur at an angle of:
40-60 degrees
A hypersthenic patient is scheduled for knee radiographs. How should the central ray be directed for the anteroposterior (AP) projection? - Perpendicular - 5 degrees caudad - 5 degrees cephalad - Angled so perpendicular to the femur
5 degrees cephalad; with larger patient the hip will lie farther from IR than the knee, and the leg will naturally lie at an angle proximally to distally. In order to align the anterior and posterior borders of the tibial plateau and demonstrate the joint space of the knee.
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
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
central ray variation due to ASIS <19 cm = 19-24 cm = >24 cm =
<19 cm = 3-5 degrees caudad (thin pelvis) 19-24 cm = 0 degrees >24 cm = 3-5 degrees cephalad (large pelvis)
From the following list, what structures and articulation should be demonstrated in the image of an AP oblique ankle. a. Talus b. cuboid c. calcaneus d. distal tibia e. distal fibula f. tibifibuluar articulation g. femorotibial articulation i. Talofibular articulation
A. Talus D. Distal tibia E. Distal fibula F. Tibiofibular articulation (joint)
What projection of the foot best demonstrates the lateral tarsals with the least superimposition of structures?
AP Oblique Foot Medial Rotation
Which projection of the foot best demonstrates the cuboid and its articulations?
AP oblique (medial rotation)
Which projection of the knee best demonstrates the proximal tibiofibular articulation without bony superimposition?
AP oblique knee projection (medial rotation)
Which projection of the foot best demonstrates the sinus tarsi?
AP oblique projection (medial rotation)
Which projection of the anke best demonstrates the talofibular joint space free from bony superimposition?
AP oblique projection ankle (medial rotation)
Which projection of the foot best demonstrates most of the tarsals with the least amount of superimposition? and also demonstrated 4th and 5th metatarsals free from superimposition
AP oblique projection foot (medial rotation)
Which projection of the knee should be used to demonstrate the patella completely superimposed on the femur?
AP projection knee
Which positioning maneuver should be performed to place the femoral neck in profile for the AP projection of the proximal femur? -also performed to prevent the femoral neck from appearing foreshortened in this projection
AP projection of the proximal femur
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
which projections of the foot will demonstrate the head of the first metatarsal equally superimposed by two sesamoid bones?
AP; it is common to see two sesamoid bones on posterior surface of head of first metatarsal. these bones should be centered over the metatarsal head on an AP or dosoplantar projection of the foot
If an image of the ankle demonstrates the lateral malleolus slightly superimposing the lateral edge of the talus, which projection was used? - Lateral - Medial Oblique - Mortise - Anteroposterior (AP)
AP; will demonstrate the medial tibiotalar and superior tibiotalar joint spaces open. The fibula will slightly superimpose the talus on an AP image.
How do images indicate that a patient has a torn ligament affecting the ankle?
An increase in the joint space on the side of the injury indicates a torn ligament
Where should the central ray enter for the lateral projections of the ankle?
At the medial malleolus
Where on the medial surface of the foot should the central ray enter the calcaneus for the lateral projection?
At the midportion of the calcaneus (1 inch distal to the medial malleolus).
How many degrees and in what direction should the central ray be directed for the axial (plantodorsal) projection of the calcaneus?
Axial Plantodorsal Calcaneus
AP or AP axial toes
CR: perp through 3rd MTP joint,, 15 degrees if joint spaces evaluation criteria: -entire toes, including distal ends of the metatarsals -no rotation of phalanges -open IP and MTP joint spaces on axial projection
For a patient prone on the radiographic table with the knee centered in the midline and the knee flexed until the lower leg forms a 40-degree angle with the table, how should the CR be directed to demonstrate the femoral intercondylar fossa?
Caudally 40 degrees
On an image of a correctly positioned AP projection of the knee, the patella should be demonstrated.
Completely superimposed on the femur
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
With reference to the lower leg, how should the foot be positioned for the lateral projection?
Dorsiflex the foot to form a 90 degree angle with the lower leg.
What other projection term refers to the AP projection of the foot?
Dorsoplantar
What procedural compensation is required for the planto dorsal axial projection for the calcaneus where teh patient cannot dorsiflex the foot sufficiently to place the plantar surface vertical?
Elevate the leg on sandbags to achieve the correct position.
Regardless of the condition of the patient, which positioning maneuver should be performed to position the foot for the lateral projections?
Ensure that the plantar surface is perpendicular to the IR.
For the lateral projection of the patella, which positioning maneuver reduces the femorpatellar joint space?
Flexing the knee more than 10 degrees
the settegast method should not be attempted until what has been ruled out by other projections?
Fracture of Patella
How should the pelvis be positioned to demonstrate the proximal femur?
From true lateral, the pelvis should be rolled posteriorly about 10 to 15 degrees
Which projection of the foot should demonstrate the metatarsals nearly superimposed on each other?
Lateral projection
For which lower limb projection should the pelvis be rotated 10 to 15 degrees from true lateral?
Lateral projection of the proximal femur
How should the femoral neck appear in the AP projection of the proximal femur?
Not foreshortened in profile
Where should the patella be demonstrated on the radiograph of the AP oblique projection of the knee with medial rotation?
Over the medial condyle of the femur
Which of the following projections of the knee best demonstrates the intercondylar fossa?
PA Axial (Holmblad Method)
Which two of the following projections may safely be used to demonstrate a horizontal fracture of the patella? (Select two) - Tangential projection, Settegast method -Posteroanterior (PA) projection - Anteroposterior (AP) Axial Intercondylar Fossa (Beclere) - Lateral projection
PA and lateral When evaluating the patella, it should be placed as close to the image receptor as possible, so ideally a PA projection will be obtained. The lateral projection can be useful to demonstrate the patella, a horizontal fracture line, or the patellofemoral joint. The Settegast method should not be used if a horizontal fracture is suspected because the degree of flexion required to obtain this image could pull superior and inferior bone fragments apart and cause further damage to the patella.
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 of the following projections of the knee best demonstrates the femoral intercondylar fossa?
PA axial projection (Camp-Coventry method)
Which projection of the knee can be accomplished with the patient upright, the affected knee flexed and its anterior surface in contact with a vertically placed IR, and the horizontally directed central ray entering the posterior aspect of the knee?
PA axial projection (Holmblad method)
What procedure should the radiographer perform if the patient is unable to turn from the supine position toward the affected side to position a fractured leg on the IR for the lateral projection?
Perform a cross-table lateral projection by placing an IR vertically between the patient's legs and directing a horizontal CR to the leg. -the IR may be placed between the legs, and the central ray may be directed from the lateral side
How and toward what centering point should the central ray be directed forthe AP oblique projection to demonstrate all five toes?
Perpendicular to the 3rd metatarsophalangeal joint
When performing an anteroposterior (AP) radiograph of the distal femur, how should the leg be adjusted? - No adjustment needed, place the leg in a comfortable position -Internally rotate the leg 15 - 20 degrees - Externally rotate the leg 15 - 20 degrees - Rotate the leg so that the toes point directly upward and the femoral condyles are equidistant to image receptor (IR)
Rotate the leg so that the toes point directly upward and the femoral condyles are equidistant to image receptor (IR) -positioning is same for AP knee, the femoral condyles equidistant to the IR
For a plantodorsal, axial calcaneus radiograph, correct patient positioning includes: -Prone, legs fully extended, with the foot plantarflexed - Supine, legs fully extended, with the foot plantarflexed - Seated, legs fully extended, with the foot dorsiflexed • -Standing, legs fully extended, with the foot resting on plantar surface
Seated, legs fully extended, with the foot dorsiflexed
Where is the patella located on a correctly positioned AP projection of the knee?
Slightly off center to the medial side of the femur
What portion of the foot should appear in profile medially if there is no rotation demonstrated on a plantodorsal (axial) projection of the calcaneus? - Ankle joint - Peroneal trochlea - Sustentaculum tali - Tuberosity
Sustentaculum tali
what best describes central ray for the projection for sesamoid bones? -The central ray is perpendicular to the image receptor and should skim the plantar surface of the foot tangentially at the first metatarsophalangeal joint -The central ray is perpendicular to the image receptor and should enter the dorsal surface of the foot tangentially at the first metatarsophalangeal joint -The central ray is directed 40 degrees cephalic and should enter the plantar surface of the foot at the first metatarsophalangeal joint -The central ray is directed 40 degrees cephalic and should enter the dorsal surface of the foot at the first metatarsophalangeal joint
The central ray is perpendicular to the image receptor and should skim the plantar surface of the foot tangentially at the first metatarsophalangeal joint
Where should the distal fibula be seen in images of the lateral projection of the foot?
The distal fibula should overlap the posterior portion of the tibia.
mortise joint
The entire ankle joint is also know as the ____. joint with talus and tibia is just tibiotalar
Which of the following evaluation criteria indicates that the knee is properly positioned for the AP projection? -The femorotibial joint space is open. -the femoral condyles are perpendicular -the proximal tibiofibular articulation is open -the patella is perp to IR
The femorotibial joint space is open.
With reference to the position of the patients leg and foot during the procedure, how is it determined that the leg has been rotated the correct number of degrees?
The intermalleolar plane should be parallel
Describe how the lesser trochanter should appear in the AP projection of the proximal femur?
The lesser trochanter should not be seen beyond the medial border of the femur, or only a very small portion of the lesser trochanter should be seen.
IF a radiographer positions the lower limb very carefully to ensure that the femoral condyles are physically superimposed, but they do not appear to be well superimposed on the image, what could have caused the image to appear that way?
The natural divergence of the beam may prevent the femoral condyles from appearing superimposed
true or false the lateral projection should demonstrate the fibula over the posterior half of the tibia
True
which is recommended in order to demonstrate the tarsometatarsal joints in the dorsoplantar projection of the foot?
angle CR 10 degrees posteriorly
what is the correct central ray entrance point for a medial oblique foot radiograph?
base of the 3rd metatarsal the midpoint of the foot corresponds to this or the 3rd tarsometatarsal joint
which method of demonstrating the intercondylar fossa places the patient in an AP axial projection?
beclere method
which of the following describes the appropriate image receptor (IR) placement for a lateral image of the distal femur? -top of IR at level of ASIS -center of IR 2 inches distal to greater trochanter -center of IR 2 inches superior to patellar apex -bottom of IR 2 inches distal to the patellar apex
bottom of IR 2 inches distal to the patellar apex
true or false the AP projection should demonstrate the distal third of the fibula without superimposition with the talus or tibia
check answers
Axial plantodorsal calcaneus collimation, CR, evaluation
collimate: 1 inch on 3 sides of the shadow of calcaneus and include 5th metatarsal base CR: 40 degrees cephalic toward heel, enters near the base of 3rd metatarsal -tape around toes to help dorsiflex -plantar surface perp Evaluation criteria: -calcanues and calcaneuocuboid joint -no rotation of calcaneus - 1st or 5th metatarsals not projected to the sides of the foot
AP leg collimation, CR, evaluation
collimation: 1 inch on the sides and 1 1/2 inches beyond the ankle and knee joints CR: perp to center of the leg -IR is diagonal -femoral condyles paralell evaluation: -ankle or knee joints on one or more images -proximal and distal articulation of the tibia and fibula moderately overlapped -fibular midshaft free of tibial superimposition
lateral leg collimation, CR, evaluation
collimation: 1 inch on the sides and 1 1/2 inches beyond the ankle and knee joints CR: perp to the midpoint of the leg -turn the patient toward the affected side with the leg on the IR -the patella perpendicular/femoral condyles -knee may be flexed if necessary to ensure true lateral -IR is diagonal evaluation: -ankle and knee joints on one or more images -distal fibula superimposed by the posterior half of the tibia -slight overlap of the tibia on the proximal fibular head -moderate separation of the tibial and fibular bodies or shafts (except at their articular ends) -possibly reduced superimposition of femoral condyles because of divergence of the beam
AP projection femur position part, collimation, CR
collimation: 1 inch on the sides and 17 inches in length CR: mid femur if can fit on one image knee included -rotate patient's extremity internally to place in true anatomic position. the extremity is naturally turned externally when lying on table. epicondyles need to be parallel -bottom of IR 2 inch below knee joint hip included -place top of IR at level of ASIS -rotate extremity 10-15 degrees internally to place femoral neck in profile
AP Oblique Mortise Joint
collimation: 1 inch on the sides of the ankle and 8 inches lengthwise to include the heel CR: perp through the ankle joint at a point midway between the malleoli -grasp distal femur area with one hand and the foot with the other -15-20 degrees until the intermalleolar plane is parallel with IR -plantar surface of foot should be placed at right angle to the leg evaluation: -entire ankle mortise joint centered to exposure area -distal tibia, fibula, and talus -talofibular and tibiotalar art open -no overlap of the anterior tubercle of the tibia and the superolateral portion of the talus with the fibula
AP ankle collimation, CR, evaluation
collimation: 1 inch on the sides of the ankle and 8 inches lengthwise to include the heel CR: perp through the ankle joint at a point midway between the malleoli -long axis of foot vertical (pointing straight up) evaluation: -ankle joint centered to the exposure area -medial and lateral malleoli -talus -no rotation of the ankle -normal overlapping of the tibiofibular articulation with the anterior tubercle slightly superimposed over the fibula -talus slightly overlapping the distal fibula -no overlapping of the medial talomalleolar articulation
AP oblique ankle collimation, CR, evaluation
collimation: 1 inch on the sides of the ankle and 8 inches lengthwise to include the heel CR: perp through the ankle joint at a point midway between the malleoli 45-degree rotation -long axis parallel w long axis of leg -dorsiflex evaluation: -distal tibia, fibula, and talus -proper 45 degree rotation of ankle -tibiofibular articulation open -distal tibia and fibula overlap some of the talus
lateral ankle collimation, CR, evaluation
collimation: 1 inch on the sides of the ankle and 8 inches lengthwise to include the heel and 5th metatarsal base CR: perp to ankle joint entering medial malleolus evaluation: -ankle joint centered to exposure area -distal tibia and fibula, talus, calcaneus, and adjacent tarsals -ankle in true lateral position -tibiotalar joint well visualized, with the medial and lateral talar domes superimposed -fibula over the posterior half of the tibia -5th metatarsal base and tuberosity should be seen to check for jones fracture
lateral knee position part, collimation, CR
collimation: 8x10 1 inch anterior to the patella and 1 inch beyond the posterior shadow (lengthwise) CR: directed to knee joint 1 inch distal to medial epicondyle at an angle of 5-7 degrees cephalad -turn patient onto affected side and pelvis not rotated -have patient bring affected knee forward and extend the other extremity behind it -flexion of 20-30 degrees is usually preferred because relaxes muscle and shows maximum volume of joint cavity -grasp epicondyles and adjust them to be perpendicular to IR (condyles superimposed)
AP knee position part, CR, collimation
collimation: 8x10 1 inch beyond all sides CR: directed to a point 1/2 inch inferior to patellar apex -make sure pelvis not rotated -with IR under patients knee flex joint slightly locate apex of the patella, and as the patient extends the knee center the IR about 1/2 inch bellow patellar apex -femoral epicondyles parallel with IR
AP oblique lateral rotation
collimation: 8x10 1 inch beyond the sides CR: 1/2 inch inferior to patellar apex (angle varies) -45 degrees laterally rotate evaluation: -medial femoral and tibial condyles -tibial plateaus -fibula superimposed over the lateral half of the tibia -margin of the patella projected slightly beyond the edge of the lateral femoral condyle -open knee joint
AP oblique knee medial rotation collimation, CR, evaluation
collimation: 8x10 1 inch beyond the sides CR: 1/2 inch inferior to patellar apex (angle varies) -45 degrees medial rotate -support elevated hip and knee of the unaffected side evaluation: -tibia and fibula separated at their proximal articulation -posterior tibia -lateral condyles of the femur and tibia -both tibial plateau -margin of patella projecting slightly beyond the medial side of the femoral condyle -open knee joint
the medial and lateral intercondylar tubercles serve as attachments for which of the following? -medial and lateral collateral ligaments -medial and lateral menisci -cruciate ligaments -patellar tendon
cruciate ligaments; the superior surface of the tibia exhibits a fairly flat surface, the tibial plateau, which articulates with the femoral condyles. Between the two articular surfaces is a bony projection (intercondylar eminence) which terminates in the medial and lateral intercondylar tubercles. these tubercles are the inferior attachments for the anterior and posterior cruciate ligaments of the knee.
where is the medial malleolus located?
distal tibia
lateral projection distal femur evaluation
evaluation: (with knee included) -The patella should be seen in profile -The patellofemoral joint space should be open -The anterior surface of the femoral condyles should be superimposed -The inferior surface of the femoral condyles should not be superimposed (with hip included) -opposite thigh not over proximal femur and hip joint -greater trochanter superimposed over distal femoral neck -lesser trochanter visible on medial aspect of proximal femur
What two metatarsal bases appear overlapped in the image of the AP oblique projection medial rotation?
first and second metatarsal
when performing a recumbent lateral projection of the knee, how should the patient's knee be positioned?
flexed 20-30 degrees; not be flexed more than 20-30 to avoid tensing of the quadriceps muscles and tendon.
what joint classification is the tibiotalar joint?
hinge joint
why is it important to have 30 degrees rotation on AP oblique foot?
if more than 30 degrees then the lateral cuneiform tends to be thrown over the others
A technologist adjusts the image receptor (IR) so that it is oriented diagonally to include the entire lower leg on a radiograph. What other modification should the technologist make in this situation? - Change to a large focal spot - Use a grid - Decrease the kVp - Increase the source-to-image distance (SID)
increase SID; Radiographic fields are typically open to 17 inches when a 40 inch SID is used. To obtain a radiographic field of greater than 17 inches, the x-ray tube will need to be raised so that the SID is 44 - 48 inches.
posteriorly, the femoral condyles are separated by a deep depression called the:
intercondylar fossa
which projection of the foot best demonstrates the sinus tarsi?
internal (medial) oblique an opening between the talus and the calcaneus that allows passage of some ligaments of the foot is called the sinus tarsi
A particular radiograph demonstrates an open proximal tibiofibular joint, the medial patella free of superimposition, and an open femorotibial joint. Which projection does this describe? - Anteroposterior (AP) knee - External oblique knee - Internal oblique knee - Lateral knee
internal oblique knee
which projection of the foot will best demonstrate cuboid and its articulations?
internal(medial) oblique ; cuboid found on lateral aspect of foot. to demonstrate should be 30 degrees medially rotated
lateral projection distal femur position part, CR, collimation
knee included -draw patient's uppermost extremity posteriorly and support it -adjust pelvis in a true lateral -flex affected knee 45 degrees make sure epicondyles perpendicular -adjust IR so bottom of it is 2 inches below knee hip included -place top of IR at level of ASIS -draw the upper most extremity posteriorly -adjust pelvis so it is rolled posteriorly just enough to prevent superimposition; 10-15 degrees from lateral position is sufficient
For patient comfort, which side of the foot (medial or lateral) should be placed in contact with the IR for the lateral projection?
lateral
Which projection of the knee best demonstrates the femoropatellar space open?
lateral projection knee
which projection of the foot will best demonstrate the longitudinal arch?
lateral weight bearing
which projection of the ankle would best demonstrate a jones fracture?
lateral; because affects the proximal end, or tuberosity, of 5th metatarsal.
which projection of the ankle would best demonstrate the distal tibiofibular joint?
medial oblique 45 degrees
In which direction (medially or laterally) should the foot be rotated for the AP oblique projection for best demonstration of the cuboid and its related articulations?
medially
In order to demonstrate the distal tibiofibular joint, how should the foot be positioned? - Medially, 45 degrees O Laterally, 45 degrees O Medially, 15 degrees O Laterally, 15 degrees
medially 45 degrees -medial is done for lower extremity// lateral common for upper the fibula is parallel to and slightly posterior to the tibia. In order to demonstrate the distal articulation between these two bones, the leg needs to be medially rotated approx 45 degrees
which of the following would be classified as an ellipsoidal (condyloid) joint? -interphalangeal -metatarsophalangeal -tarsometatarsal -intertarsal
metatarsophalangeal; found at distal ends of metatarsals. freely movable and allow the following types of movement: flexion, extension, abduction, adduction
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 structure of the knee is best demonstrated with the tangential projection?
patella
Upon review of an anteroposterior (AP) image of the lower leg the technologist notices that the head of the fibula is almost entirely superimposed by the tibia. Which of the following descriptions best applies to this image? - Patient is positioned correctly - Patient's leg is internally rotated too much - Patient's leg is externally rotated too much - Patient's foot is not dorsiflexed
patient is externally rotated too much; the fibula is parallel and slightly posterior to the tibia. on correct AP lower leg the head of the fibula will slightly superimpose the lateral condyle of the tibia. As the leg is externally rotated, the fibula will be progressively more superimposed by the tibia.
With reference to the plane of the IR, the plantar surface of the foot should be? for the axial projection of the calcaneus?
perpendicular
in which position/projection will the talocalcaneal joint (subtalar ) be visualized?
plantodorsal projection
Which area of the knee should the central ray enter for the PA axial projection (Holmblad method)? -posterior -anterior -lateral condyle -medial condyle
posterior
The technologist evaluates an anteroposterior (AP) projection of the tibia and notices that both joints are included on the image, the fibula lies parallel to the tibia, and the proximal tibiofibular joint is open. What is the correct action for this technologist to take next? - No further action is needed, this is an acceptable image - Repeat the image because it was internally rotated - Repeat the image because it was externally rotated - Repeat the image because the leg was not parallel with the image receptor
repeat the image because it was internally rotated; The fibula lies parallel and on the posterior surface of the tibia. A correctly positioned leg radiograph will demonstrate the head of the fibula slightly superimposing the lateral tibial condyle and the lateral malleolus slightly superimposing the distal tibia. The shafts of the fibula and tibia will be parallel on the radiograph. Internally rotating the leg can be used to open the proximal tibiofibular joint.
-which method of the tangential projection of the patella requires a 90-degree minimum flexion of the knee?
settegast method
which of the following positions is used to demonstrate vertical patellar fractures and patellofemoral articulations? -AP knee -lateral knee -tangential patella -tunnel view
tangential patella
What can be said of a lateral projection ankle radiograph that demonstrates superimposition of the medial and lateral talar domes and the fibula superimposed over the posterior half of the tibia? - This is a correctly positioned lateral ankle radiograph - The image is externally rotated -The image is internally rotated - The foot is not dorsiflexed
this is correctly positioned
the two flat, superior surfaces of the tibia are called:
tibial plateaus
why do we do axial for toe projections?
to open the joint spaces and reduce foreshortening
true or false the AP projection should demonstrate the joint space between the medial malleolus and the talus without any overlapping of structures
true
true or false the tuberosity and base of the 5th metatarsal should be demonstrated as a lateral projection of the ankle
true
true or false The AP projection of the leg should demonstrate the fibula without any overlapping with the tibia
true
true or false: An AP knee demonstrates the tibial eminences
true
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 should the pelvis be positioned to demonstrate the distal femur?
true lateral
Which of the following projections will best demonstrate pathology of the ligaments of the longitudinal arch of the foot? - Anteroposterior (AP) with stress - Lateral (external) oblique - Plantodorsal - Weight-bearing lateral
weight -bearing lateral; Weight-bearing lateral images of the foot are used to evaluate the bony structure and the ligaments of the longitudinal arches of the foot under the full weight of the body.
