ARRT Radiography Exam Quiz: Position Lower Extremity Imaging
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Position Lower Extremity ImagingQuestion 1 of 17

A radiographer is preparing to perform a tunnel (intercondylar fossa) projection of the knee using the Camp-Coventry method. Which of the following MOST accurately describes the correct positioning and anatomy demonstrated?

The patient is supine with the knee fully extended; the CR is directed perpendicular to the IR; this demonstrates the intercondylar space between the anterior femoral condyles
The patient is prone with the knee in full extension; the CR is directed 15 degrees cephalad to the tabletop; this angulation projects the intercondylar notch between the condyles
The patient is prone with the knee flexed 40 degrees; the CR is directed perpendicular to the lower leg, demonstrating the intercondylar fossa and tibial spines.
The patient is standing with the knee flexed; weight-bearing position opens the intercondylar notch for the Camp-Coventry projection
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ARRT Radiography Exam Quiz

ARRT Radiography Exam Quiz: Position Lower Extremity Imaging

Practice Position Lower Extremity Imaging in ARRT Radiography Exam with focused quiz questions that help you check what you know, review explanations, and build confidence with test-style prompts.

What this quiz covers

This quiz focuses on Position Lower Extremity Imaging, giving you a quick way to practice the rules, question types, and explanations that matter most for ARRT Radiography Exam.

How to use this quiz

Try each quiz question before looking at the correct answer. Use the explanations to review missed ideas, then come back to similar questions until the pattern feels familiar.

All questions

Question 1

A radiographer is preparing to perform a tunnel (intercondylar fossa) projection of the knee using the Camp-Coventry method. Which of the following MOST accurately describes the correct positioning and anatomy demonstrated?

  1. The patient is supine with the knee fully extended; the CR is directed perpendicular to the IR; this demonstrates the intercondylar space between the anterior femoral condyles
  2. The patient is prone with the knee in full extension; the CR is directed 15 degrees cephalad to the tabletop; this angulation projects the intercondylar notch between the condyles
  3. The patient is prone with the knee flexed 40 degrees; the CR is directed perpendicular to the lower leg, demonstrating the intercondylar fossa and tibial spines. (correct answer)
  4. The patient is standing with the knee flexed; weight-bearing position opens the intercondylar notch for the Camp-Coventry projection
Explanation: How to get the right answer: The Camp-Coventry method requires the patient to be prone with the knee flexed to 40 to 50 degrees, with the lower leg supported at this angle. The CR is directed perpendicular to the lower leg surface (not to the horizontal tabletop) and centered at the popliteal fossa. This specific combination of prone position, knee flexion, and perpendicular-to-lower-leg CR directs the beam through the posterior knee and into the intercondylar notch, imaging structures that are obscured on standard AP and lateral views. The CR direction perpendicular to the lower leg rather than to the table is the critical technical detail; the lower leg flexion angle itself determines the effective beam path through the notch. Why the other answers are wrong: Choice A positions the patient supine with the knee extended; the supine extended position does not project the beam through the intercondylar fossa, because prone positioning with knee flexion is required to open the posterior notch to the beam. Choice B uses a fixed cephalad angle to the tabletop with the knee straight; the Camp-Coventry CR must be perpendicular to the lower leg rather than a fixed table-referenced angle, and knee flexion is required to direct the beam through the posterior intercondylar space. Choice D requires the patient to stand; the Camp-Coventry method is performed in the prone position, not standing; a weight-bearing tunnel view variant exists but is not the standard Camp-Coventry technique. Big idea to remember: Camp-Coventry tunnel view: prone, knee flexed 40 to 50 degrees, CR perpendicular to the lower leg (not the table), centered at the popliteal fossa; this demonstrates the intercondylar notch, tibial spines, and posterior femoral condylar surfaces; clinical use includes osteochondral loose bodies and cruciate ligament avulsion detection.

Question 2

A patient requires an AP pelvis radiograph but cannot lie supine due to respiratory distress. The technologist positions the patient in a 30-degree semi-upright position using the table's elevating capability. To maintain proper anatomical relationships equivalent to a standard supine AP pelvis, what central ray adjustment is necessary?

  1. Angle the central ray 10 degrees cephalad to counteract the gravitational effects on pelvic positioning
  2. Angle the central ray 15 degrees caudad to partially compensate for the patient's positioning change
  3. Angle the central ray 30 degrees caudad to maintain the same beam-to-anatomy relationship as the standard supine position
  4. Maintain perpendicular central ray to the image receptor, accepting that some geometric changes are unavoidable in adapted positioning (correct answer)
Explanation: When adapting standard radiographic positions for patients with medical limitations, you must balance maintaining diagnostic quality with patient safety and comfort. This question tests your understanding of when to modify technique versus when to accept positioning compromises. The correct approach is D - maintain a perpendicular central ray to the image receptor. In semi-upright positioning, the patient's anatomy naturally adjusts to gravity, and the pelvis maintains its essential relationships for diagnostic purposes. A perpendicular beam ensures proper magnification, distortion control, and optimal image geometry. While there may be minor changes in anatomical presentation compared to supine positioning, these are typically within acceptable diagnostic limits and don't compromise the examination's clinical value. A is incorrect because a 10-degree cephalad angle would actually worsen foreshortening of pelvic structures and create unnecessary distortion. Gravitational effects don't require beam compensation in this scenario. B is wrong because a 15-degree caudad angle would elongate anatomical structures and potentially project the symphysis pubis incorrectly, degrading image quality rather than improving it. C represents a significant technical error. A 30-degree caudad angle would severely distort the pelvis, create extreme elongation, and likely result in a non-diagnostic image. This degree of angulation far exceeds what's needed for any standard pelvic projection. Study tip: Remember that patient comfort modifications often require accepting minor positioning variations rather than extreme technical compensations. When in doubt, maintain standard beam geometry and document the positioning adaptation - this typically produces better diagnostic images than dramatic angle adjustments.

Question 3

A patient requires bilateral AP weight-bearing knee radiographs for joint space evaluation. The patient can bear weight but reports significant discomfort when standing with feet parallel. The technologist observes the patient naturally stands with feet externally rotated approximately 15 degrees. How should this positioning variation be managed to ensure diagnostic quality images?

  1. Allow the natural foot position but internally rotate both legs at the knee level to achieve proper AP alignment of the knee joints
  2. Maintain the patient's comfortable foot position and accept the slight external rotation as it minimally affects joint space demonstration
  3. Position both feet parallel despite discomfort, as standardized positioning is essential for accurate bilateral joint space comparison (correct answer)
  4. Use the natural external foot rotation but compensate by angling the central ray medially to maintain proper knee joint alignment
Explanation: For bilateral weight-bearing knee comparisons, standardized positioning with feet parallel is crucial for accurate joint space assessment and bilateral comparison. External rotation of the feet causes external rotation of the entire leg, which alters the projection of the medial and lateral joint spaces, potentially masking or exaggerating joint space narrowing. While patient comfort is important, diagnostic accuracy takes precedence. Choice A creates inconsistent positioning. Choice B compromises diagnostic quality. Choice D incorrectly attempts to compensate with central ray angulation rather than correcting the fundamental positioning issue.

Question 4

A patient with a suspected Jones fracture requires an oblique foot radiograph. The technologist positions the patient supine with the affected foot rotated 30 degrees medially. The resulting image demonstrates good visualization of the cuboid and lateral cuneiform, but the base of the fifth metatarsal appears foreshortened and overlapped by the fourth metatarsal. What modification would best demonstrate the suspected fracture site?

  1. Increase medial rotation to 45 degrees and angle the central ray 10 degrees toward the heel to elongate the fifth metatarsal
  2. Decrease medial rotation to 15-20 degrees and maintain perpendicular central ray to reduce metatarsal overlap (correct answer)
  3. Maintain 30-degree medial rotation but angle the central ray 15 degrees toward the toes to project the fifth metatarsal clear of overlap
  4. Change to lateral rotation of 30 degrees to better profile the lateral aspect of the foot and fifth metatarsal base
Explanation: A Jones fracture occurs at the base of the fifth metatarsal. The described positioning (30 degrees medial rotation) is excessive for demonstrating this area and causes overlap of the fourth and fifth metatarsals. Reducing the medial rotation to 15-20 degrees provides better separation of the lateral metatarsals while still maintaining adequate visualization of the midfoot structures. Choice A increases rotation, worsening overlap. Choice C attempts to solve a rotation problem with angulation. Choice D (lateral rotation) would project the fifth metatarsal medially, creating more overlap with other structures.

Question 5

A technologist is positioning a patient for a lateral knee examination to evaluate a possible tibial plateau fracture. The patient is placed in lateral recumbent position with the affected knee flexed 20 degrees. After taking the radiograph, the image shows the posterior aspects of the femoral condyles separated by 3mm, with the medial condyle positioned posterior to the lateral condyle. What does this positioning error indicate about the patient's rotation?

  1. The patient is rotated too far anterior, and the posterior separation indicates insufficient medial condyle visualization
  2. The patient is rotated too far posterior, and the medial condyle positioning confirms excessive lateral rotation of the knee (correct answer)
  3. The patient positioning is acceptable, as slight condylar separation is expected in lateral knee projections for trauma evaluation
  4. The patient is rotated too far anterior, and the medial condyle's posterior position indicates the lateral condyle needs to move posteriorly
Explanation: In a properly positioned lateral knee, the posterior aspects of the femoral condyles should be superimposed. When the medial condyle appears posterior to the lateral condyle with 3mm separation, this indicates the patient is rotated too far posterior (or laterally rotated). The medial condyle naturally lies slightly posterior to the lateral condyle anatomically, so excessive posterior patient rotation exaggerates this relationship. Choice A incorrectly identifies the rotation direction. Choice C accepts suboptimal positioning. Choice D correctly identifies anterior rotation but provides incorrect reasoning about the medial condyle position.

Question 6

A patient presents for a lateral foot examination with a clinical history of possible Lisfranc injury. The technologist positions the patient in lateral recumbent position with the affected foot in contact with the image receptor. Upon image review, the navicular and cuboid bones show good separation, but the metatarsal bases demonstrate significant overlap, particularly between the second and third metatarsals. The calcaneus and talus show proper superimposition. What is the most likely cause of the metatarsal overlap?

  1. The foot is positioned with excessive plantar flexion, altering the normal architectural relationships of the metatarsals
  2. The central ray is angled too far toward the heel, causing convergence of the metatarsal projections
  3. The patient's leg is rotated too far anteriorly, causing the medial metatarsals to project over the lateral metatarsals (correct answer)
  4. The patient's leg is rotated too far posteriorly, causing the lateral metatarsals to project over the medial metatarsals
Explanation: When evaluating lateral foot positioning problems, focus on how patient rotation affects the projection of anatomical structures. The key clue here is that the navicular and cuboid show good separation while the calcaneus and talus demonstrate proper superimposition - this indicates the hindfoot positioning is correct, but there's a rotation issue affecting the forefoot. In a properly positioned lateral foot, the metatarsals should show minimal overlap. When the patient's leg rotates too far anteriorly (toward a more supine position), the medial aspect of the foot tilts upward while the lateral aspect remains down. This causes the medial metatarsals (first and second) to project above and overlap the lateral metatarsals (fourth and fifth), with the second and third metatarsals showing particularly significant overlap as described. Looking at the incorrect options: Answer A suggests plantar flexion as the cause, but plantar flexion would affect the overall foot architecture and wouldn't selectively cause metatarsal overlap while maintaining good tarsal bone relationships. Answer B proposes central ray angulation issues, but incorrect CR angulation would cause distortion throughout the entire foot, not isolated metatarsal overlap with proper hindfoot positioning. Answer D describes posterior rotation, which would actually cause the opposite effect - lateral metatarsals projecting over medial ones. Remember that in lateral foot positioning, when you see isolated forefoot overlap with proper hindfoot alignment, think rotation. Anterior leg rotation causes medial-over-lateral metatarsal overlap, while posterior rotation causes lateral-over-medial overlap. The hindfoot bones (calcaneus/talus) are less sensitive to minor rotational changes than the forefoot structures.

Question 7

During an oblique ankle examination (mortise view), the technologist positions the patient supine with the leg internally rotated 15-20 degrees. The resulting image shows the tibiofibular joint space is well demonstrated, but the medial malleolus appears shortened and the lateral malleolus is elongated. The talus demonstrates good visualization without overlap. What positioning modification would optimize the malleolar demonstration while maintaining the tibiofibular joint visualization?

  1. Increase internal rotation to 25-30 degrees to better align both malleoli perpendicular to the image receptor
  2. Decrease internal rotation to 10-15 degrees to reduce the foreshortening effect on the medial malleolus
  3. Maintain current rotation but angle the central ray 5-10 degrees medially to compensate for malleolar positioning
  4. The current positioning is optimal for mortise view evaluation, as perfect malleolar symmetry is not the primary objective (correct answer)
Explanation: The mortise view is specifically designed to demonstrate the tibiofibular joint space and ankle mortise joint without talar overlap. The described image shows optimal mortise positioning with good tibiofibular joint space and clear talar visualization. Some asymmetry in malleolar appearance is expected and acceptable in this projection because the malleoli are at different anatomical angles. The primary objective is joint space demonstration, not malleolar symmetry. Choices A and B would compromise the tibiofibular joint visualization. Choice C attempts unnecessary compensation that would distort the joint relationships.

Question 8

A patient presents for an AP hip examination following internal fixation surgery. The surgical report indicates placement of a dynamic hip screw for intertrochanteric fracture repair. When positioning for the AP projection, the technologist notes the patient has limited internal rotation due to surgical precautions. The leg can only be rotated internally 5 degrees instead of the standard 15-20 degrees. What is the primary radiographic consequence of this positioning limitation?

  1. The femoral neck will appear foreshortened, and the lesser trochanter will be more prominently visualized than optimal (correct answer)
  2. The greater trochanter will be projected over the femoral neck, obscuring visualization of the surgical hardware
  3. The acetabulum will appear distorted, and the femoral head position within the joint space will be misrepresented
  4. The surgical hardware will appear magnified and distorted due to increased object-to-image receptor distance
Explanation: Internal rotation of the leg places the femoral neck parallel to the image receptor and minimizes visualization of the lesser trochanter. With limited internal rotation (5 degrees vs. standard 15-20 degrees), the femoral neck remains somewhat angled, causing foreshortening, and the lesser trochanter will be more prominent than in the optimal projection. This is particularly important when evaluating surgical hardware placement. Choice B is incorrect as the greater trochanter position doesn't significantly change with this degree of rotation. Choice C overstates the acetabular effects. Choice D incorrectly relates the issue to magnification rather than geometric positioning.

Question 9

During a lateral knee examination, the technologist positions the patient in lateral recumbent position with the affected knee flexed 20-30 degrees. Upon reviewing the image, the patella appears directly superimposed over the femoral condyles, and the fibular head is completely obscured by the tibia. What positioning adjustment would best improve the anatomical demonstration?

  1. Increase knee flexion to 45-50 degrees to better separate the patella from the femoral condyles and improve fibular head visualization
  2. Rotate the patient slightly posterior to separate the femoral condyles and move the fibular head anterior to the tibial plateau (correct answer)
  3. Rotate the patient slightly anterior to separate the femoral condyles and project the fibular head posterior to the tibia
  4. Decrease knee flexion to 10-15 degrees while maintaining the current patient rotation to optimize patellar and fibular positioning
Explanation: The described image indicates the patient is rotated too far anteriorly. In a properly positioned lateral knee, the femoral condyles should be superimposed, and the fibular head should be visible posterior to the tibial plateau, not completely obscured. Rotating the patient slightly posterior (toward the back) will separate the condyles appropriately and project the fibular head to its proper anatomical position. Choice A incorrectly focuses on flexion rather than rotation. Choice C would worsen the rotation. Choice D addresses flexion but doesn't correct the primary rotation issue.

Question 10

During positioning for a lateral ankle radiograph, a patient with limited mobility cannot lie in the standard lateral recumbent position. The technologist decides to perform the examination with the patient seated and the leg extended. To maintain the same anatomical relationships as the standard lateral position, how should the central ray be directed?

  1. Horizontal beam perpendicular to the medial aspect of the ankle, parallel to the floor and table surface (correct answer)
  2. Angled 15-20 degrees cephalad from horizontal to compensate for the altered patient position and gravity effects
  3. Angled 10-15 degrees caudad from horizontal to maintain proper joint space demonstration in the seated position
  4. Horizontal beam angled 5-10 degrees posteriorly to account for the natural forward lean of the seated patient
Explanation: When adapting a lateral ankle from recumbent to seated position, the key is maintaining the same anatomical relationships. A horizontal beam perpendicular to the medial aspect of the ankle achieves the same geometric relationship as the standard vertical beam in lateral recumbent position. The beam-to-anatomy relationship remains constant regardless of patient orientation. Choices B and C incorrectly suggest compensation angles that would distort the anatomy. Choice D addresses patient lean but doesn't maintain the fundamental perpendicular relationship needed for proper lateral ankle demonstration.

Question 11

A patient presents for an AP ankle radiograph with a clinical history of lateral ankle pain following inversion injury. During positioning, the technologist notes the patient cannot dorsiflex the foot to 90 degrees due to pain. The foot remains in slight plantar flexion at approximately 110 degrees. What is the most appropriate compensation to maintain proper radiographic anatomy demonstration?

  1. Angle the central ray 10-15 degrees cephalad to compensate for the plantar flexion and maintain perpendicular alignment to the ankle joint (correct answer)
  2. Angle the central ray 10-15 degrees caudad to compensate for the plantar flexion and maintain proper joint space visualization
  3. Maintain perpendicular central ray angulation and accept the slight geometric distortion as unavoidable due to patient condition
  4. Rotate the entire leg internally 10-15 degrees to compensate for the altered foot position and maintain anatomical relationships
Explanation: When the foot cannot be positioned at the standard 90-degree angle due to plantar flexion, angling the central ray cephalad (toward the head) compensates for this positioning limitation. This maintains perpendicular alignment to the ankle joint space and tibiotalar joint, ensuring proper demonstration of joint spaces and bony anatomy. Choice B (caudad angulation) would worsen the geometric distortion. Choice C accepts unnecessary distortion when compensation is possible. Choice D incorrectly attempts to compensate with leg rotation, which would alter the AP projection.

Question 12

A radiographer is performing an AP projection of the knee on a patient with a suspected tibial plateau fracture. The patient is supine with the knee extended. Which of the following MOST accurately describes the correct central ray direction and the anatomy that confirms the joint space is adequately demonstrated?

  1. The CR is directed 5 to 7 degrees cephalad, centered one-half inch distal to the patella apex; this angulation opens the joint space by aligning the beam parallel to the tibial plateau. (correct answer)
  2. The CR is directed perpendicular to the IR, centered one-half inch distal to the apex of the patella; a perpendicular CR with the knee fully extended always produces an open joint space regardless of patient anatomy
  3. The CR is directed 15 degrees caudad to the IR; caudad angulation is required to open all knee joint spaces
  4. The CR is always directed perpendicular to the IR regardless of tibial plateau slope; angulation is only required for the lateral knee projection
Explanation: How to get the right answer: The tibial plateaus slope posteriorly approximately 5 to 7 degrees from the horizontal plane in most adults. If the CR is directed perpendicular to a horizontal IR, it passes obliquely through the joint rather than parallel to the tibial surface, causing the joint space to appear foreshortened. A 5 to 7 degree cephalad CR angulation corrects for this slope by tilting the beam to run parallel to the tibial plateau surface, opening the joint space on the image. The confirmation criterion is a clearly open, non-foreshortened joint space with the tibial plateau cortex appearing as a single clean line rather than a double cortical image from partial condylar superimposition. Why the other answers are wrong: Choice B claims a perpendicular CR always opens the joint space; the tibial plateau slope means a perpendicular beam does not pass parallel to the joint surface, and some cephalad angulation is required for true joint space visualization in most adults. Choice C applies 15 degrees caudad; a caudad angle would further close the joint space by increasing the divergence between the beam and the tibial plateau rather than correcting for the slope. Choice D reserves angulation for the lateral only; the 5 to 7 degree cephalad angulation is specifically for the AP knee to compensate for posterior tibial plateau slope and is a distinct requirement from the lateral projection. Big idea to remember: AP knee: CR 5 to 7 degrees cephalad, centered one-half inch distal to the patellar apex; this compensates for posterior tibial plateau slope and opens the joint space; a non-foreshortened joint space with a single tibial plateau cortical line confirms adequate technique.

Question 13

A radiographer is performing a mortise view of the ankle on a patient following a twisting injury with suspected syndesmotic ligament damage. Which of the following MOST accurately describes how the mortise view differs from the standard AP ankle, and what anatomy it specifically demonstrates?

  1. The mortise view and the AP ankle are identical projections; "mortise" is simply an alternative name for the standard AP ankle
  2. The mortise view requires 15-20 degrees internal rotation to visualize the ankle mortise joint space without malleolar superimposition, assessing syndesmotic ligament injury. (correct answer)
  3. The mortise view requires 15 to 20 degrees of external rotation so the medial malleolus is profiled away from the fibula
  4. The mortise view uses a 15 degree caudad CR angle to project the tibiotalar joint in profile without relying on foot rotation
Explanation: How to get the right answer: The ankle mortise is the three-sided articulation surrounding the talar dome, formed by the medial malleolus medially, the tibial plafond superiorly, and the lateral malleolus laterally. The mortise view positions the ankle with 15 to 20 degrees of internal rotation so that both malleoli are equidistant from the IR, allowing all three sides of the mortise to be seen simultaneously without malleolar superimposition. The medial clear space, the tibial plafond, and the lateral clear space are all visible at once. A standard AP ankle performed without this specific rotation will partially superimpose the lateral clear space because the fibula lies posterior to the tibia; the mortise view is specifically designed to open all three aspects of the joint. Syndesmotic injuries produce widening of the medial clear space beyond 4 mm, which the mortise view is designed to detect. Why the other answers are wrong: Choice A equates the mortise view with the standard AP ankle; the specific internal rotation required for the mortise view distinguishes it from a generic AP ankle and is designed to open all three aspects of the joint space simultaneously. Choice C uses external rotation; external rotation would move the lateral malleolus further posterior relative to the medial malleolus, superimposing the lateral mortise rather than opening it. Choice D applies caudad angulation; CR angulation is not the defining feature of the mortise view and does not substitute for the internal rotation that opens the three-sided joint space. Big idea to remember: Mortise view: AP ankle with 15 to 20 degrees internal rotation so the intermalleolar line is parallel to the IR; this opens all three sides of the ankle mortise simultaneously; primary use is syndesmotic injury detection, with medial clear space widening beyond 4 mm indicating ligamentous disruption.

Question 14

A radiographer is performing an AP axial projection of the calcaneus (axial heel). The patient is seated with the foot dorsiflexed. Which of the following MOST accurately describes the CR direction and the anatomy demonstrated?

  1. The CR is directed perpendicular to the IR, centered at the midcalcaneus; a perpendicular CR demonstrates the calcaneus in a true AP orientation
  2. The CR is directed 15 degrees caudad, centered at the heel; caudad angulation projects the calcaneus below the ankle mortise for axial evaluation
  3. The calcaneus is only adequately demonstrated on the lateral foot projection; a dedicated calcaneal axial view is not a standard radiographic examination
  4. The CR is directed 40 degrees cephalad, centered at the midcalcaneus, demonstrating the calcaneus and subtalar joint in a true axial projection. (correct answer)
Explanation: How to get the right answer: The calcaneus lies at an angle to the horizontal plane; its posterior tuberosity is lower and its anterior process is higher in the weight-bearing orientation. To image the calcaneus along its long axis and produce a true axial view, the CR must be directed steeply cephalad from below (from the plantar surface of the heel toward the patient's head). A 40-degree cephalad angle achieves this geometry, passing through the calcaneus from plantar to dorsal along its long axis and demonstrating the posterior facet of the subtalar joint, the sustentaculum tali, the tuberosity, and the body of the calcaneus. This is the standard AP axial (plantodorsal) calcaneus projection. Why the other answers are wrong: Choice A uses a perpendicular CR; a beam directed perpendicular at the heel would pass tangentially to the calcaneal long axis rather than along it, foreshortening the bone and poorly demonstrating the subtalar facets and internal calcaneal structure. Choice B uses caudad angulation; a caudad angle directs the beam away from the calcaneus and toward the tabletop rather than through the calcaneal long axis in the cephalad direction required for the axial view. Choice C eliminates the calcaneal axial projection; the AP axial calcaneus is a standard and clinically important examination, and the lateral foot alone does not adequately demonstrate the calcaneal width, the sustentaculum tali, or the subtalar joint facets. Big idea to remember: Axial calcaneus (AP axial): foot dorsiflexed, CR 40 degrees cephalad, centered at the midcalcaneus; this directs the beam along the calcaneal long axis and demonstrates the body, sustentaculum tali, tuberosity, and posterior subtalar facet; primary use includes calcaneal fractures and subtalar joint evaluation.

Question 15

A radiographer is producing an AP projection of the pelvis for a patient suspected of having a fracture. The patient is supine with both legs extended. Which of the following MOST accurately describes the correct foot position and the anatomy best evaluated on this projection?

  1. Internally rotate feet 15-20 degrees; this optimally visualizes femoral necks and evaluates iliac wings, acetabula, pubic symphysis, and sacroiliac joints for fractures. (correct answer)
  2. The feet should be externally rotated (toes pointing outward); external rotation profiles the greater trochanters and demonstrates avulsion injuries at the trochanteric level
  3. The foot position is irrelevant for pelvic trauma radiography; only the bony pelvis anatomy is evaluated and foot position does not affect it
  4. Maximum internal rotation (feet crossed toward the midline) produces the best femoral neck visualization for trauma
Explanation: How to get the right answer: In the natural supine position, the lower extremities are externally rotated due to the anatomical anteversion of the femoral necks; the necks are not parallel to the IR and appear foreshortened. Internal rotation of 15 to 20 degrees counteracts this by rotating the femoral necks into a plane parallel to the IR, where they can be demonstrated in their true length. This is critical for detecting subtle femoral neck fractures, particularly impacted fractures where the fracture line may be nearly invisible on a foreshortened image. Simultaneously, the AP pelvis demonstrates all pelvic bony structures, making this a comprehensive trauma survey projection. Why the other answers are wrong: Choice B prescribes external rotation; external rotation increases femoral neck foreshortening by rotating the neck further out of the imaging plane, which is the opposite of what is needed. Choice C claims foot position is irrelevant; foot position directly determines the femoral neck's orientation relative to the IR and is highly relevant for trauma assessment, where foreshortening can conceal subtle fracture lines. Choice D uses maximum internal rotation with feet crossed; this excessive rotation would distort normal femoral neck anatomy and is not the clinical standard. Big idea to remember: AP pelvis foot position: 15 to 20 degrees internal rotation; the femoral neck is naturally externally rotated in the supine position, and internal rotation places it parallel to the IR for true-length demonstration; this is essential for detecting subtle femoral neck fractures that may be missed on a foreshortened image.

Question 16

A radiographer is preparing for an AP projection of the pelvis on an emergency department patient following a motor vehicle accident. The patient reports severe right hip pain, and the right lower extremity appears shortened and externally rotated compared to the left. Which of the following MOST accurately describes the appropriate positioning modification?

  1. Proceed with standard bilateral 15 to 20 degrees internal rotation of both feet; standard positioning should always be applied regardless of patient presentation to ensure comparable bilateral images
  2. Apply gentle traction to the right lower extremity before positioning; traction reduces the fracture and allows the standard AP pelvis to be obtained
  3. Position the right leg as presented without internal rotation; internally rotate the left leg to optimize imaging of the unaffected side and document the clinical presentation and positioning limitation. (correct answer)
  4. Perform the AP pelvis with both hips and knees flexed and feet flat on the table; this position avoids the need for rotational positioning of the legs
Explanation: How to get the right answer: A shortened and externally rotated lower extremity following trauma is a classic clinical presentation of a displaced hip fracture (femoral neck or intertrochanteric) or posterior hip dislocation. Any forced rotation of an unstable fractured femur or dislocated hip risks displacing fracture fragments further, injuring neurovascular structures (the sciatic nerve in posterior dislocation, superior gluteal vessels in pelvic fractures), or increasing the risk of avascular necrosis of the femoral head. The radiographer must never force rotation of a suspected fractured or dislocated extremity. The affected limb is imaged in the position it presents; the unaffected contralateral side can be positioned normally. Documentation of the clinical presentation is essential so the interpreting radiologist can account for the positioning limitation. Why the other answers are wrong: Choice A applies standard bilateral internal rotation; forced internal rotation of a potentially fractured or dislocated femur can displace fragments and cause significant patient harm, making this option clinically dangerous. Choice B applies traction; traction is a physician-authorized intervention and not a radiographic positioning technique; the radiographer must never independently apply traction to a suspected fracture. Choice D brings both hips into flexion; any positioning requiring movement or manipulation of the injured hip (including flexion) is equally contraindicated when hip fracture or dislocation is suspected. Big idea to remember: Suspected hip fracture or dislocation: do NOT force rotation; image the affected extremity in the position it presents; apply standard positioning only to the unaffected contralateral limb; inform the radiologist of the positioning limitation and document the clinical presentation.

Question 17

A radiographer is evaluating an AP projection of the knee and notices that the fibular head appears superimposed over approximately one-third of the proximal tibial shaft on the lateral aspect. The patient has no known fibular pathology. Which of the following MOST accurately evaluates this finding?

  1. The fibular head superimposing one-third of the lateral tibial shaft indicates the knee is externally rotated; this finding requires internal rotation correction before the image is accepted
  2. The fibular head superimposing one-third of the tibial shaft indicates correct positioning for a true AP knee without rotation. (correct answer)
  3. No fibular superimposition over the tibia is acceptable on the AP knee; the fibula should be entirely clear of the tibial cortex on a true AP projection
  4. The fibular head should completely overlie the tibia on the AP knee; complete superimposition confirms a true AP projection
Explanation: How to get the right answer: The fibula lies slightly posterior and lateral to the tibia. On a true AP knee with no rotation, the fibular head projects over approximately the lateral one-third of the proximal tibial shaft. This partial superimposition is the expected normal finding confirming correct rotation for the AP knee. When the leg is internally rotated, the fibula moves further posterior, superimposing less or none of the tibia. When the leg is externally rotated, the fibula rotates anteriorly and medially, superimposing more than one-third of the tibial cortex. One-third fibular-tibial overlap is the standard rotation confirmation criterion used in AP knee image quality assessment. Why the other answers are wrong: Choice A diagnoses external rotation from one-third overlap; one-third superimposition is actually the expected finding for a true AP and is not an indicator of external rotation; external rotation would produce more than one-third overlap. Choice C requires no superimposition; complete absence of fibular-tibial superimposition indicates internal rotation of the leg, not a true AP. Choice D requires complete superimposition of the fibular head over the tibia; complete overlap indicates significant external rotation, not a true AP. Big idea to remember: AP knee fibular head criterion: approximately one-third of the fibular head superimposed over the lateral tibial cortex confirms a true AP with no rotation; less than one-third or no superimposition indicates internal rotation; more than one-third to complete superimposition indicates external rotation.