Radiography Techniques and Procedures Quiz

The source image receptor distance (SID) for lower limb radiography is 40 inches (100 cm).

Grids are required for foot and ankle studies to reduce scatter radiation.

With careful and close collimation, gonadal shielding is usually not needed during lower limb radiography.

It is recommended that the anatomy be centered to the IR for digital radiography.

A kVp range between 50 and 55 is used for knee radiography.

Immobilization devices should be used for pediatric patients instead of manual holding.

Bariatric patients should be allowed to wear pants for lower limb radiography.

Paget disease, also known as osteitis deformans, is a chronic bone disease that causes bone thickening and weakening.

In a true AP ankle projection, the lateral aspect of the ankle joint should not be fully open. This indicates that the long axis of the foot was not perpendicular to the image receptor.

In an AP mortise projection of the ankle, the lateral malleolus overlapping the talus indicates that the foot was internally rotated, leading to poor visualization of the distal tibiofibular joint.

The lack of space between the femorotibial joints in an AP knee projection suggests a potential positioning error, particularly in a young and healthy patient. The knee needs to be slightly flexed for better joint separation.

In an AP oblique knee projection, complete overlap of the proximal tibia and fibula indicates that the patient's leg was not rotated enough. Increased medial rotation is needed to correct the overlap.

A lateral recumbent knee projection showing the posterior border of the medial femoral condyle slightly posterior to the lateral condyle, with the fibular head superimposed by the tibia, indicates that the knee was not fully extended.

A tangential projection of the foot, such as an oblique projection, is necessary to better visualize the medial aspect of the foot, particularly the base of the first metatarsal, in trauma cases.

If an AP tibia and fibula projection excludes the ankle joint but the lateral view includes both knee and ankle, the technologist should reposition the patient to include the ankle in the AP image.

Asymmetrical distal femoral condyles, articular facets, and intercondylar fossa in a PA axial projection indicate potential positioning errors such as rotation or tilting of the femur. The patient's femur should be aligned parallel to the image receptor.

A condition characterized by wear and tear on the knee joint, leading to pain, stiffness, and reduced mobility.

The structural arches that run along the length of the foot, providing support and flexibility. These arches are crucial for weight bearing and stability.

Loose fragments of bone or cartilage within a joint, often caused by injury or degenerative conditions.

A painful condition that affects the tibial tuberosity (bony bump just below the knee), causing inflammation and pain.

The inner portion of the femur (thigh bone) that articulates with the tibia (shin bone) to form the knee joint.

The knee joint should be included in an initial study of tibia trauma, even if symptoms are in the middle and distal aspects, because it can reveal associated injuries. For example, the knee joint might have a fracture or ligament damage that isn't obvious from just looking at the middle and distal parts of the tibia.

For a lateral projection of the tibia and fibula in an adult, the image receptor (IR) should be placed parallel to the leg, ensuring that both bones are included in the image. This means the IR is positioned neither diagonally nor transversely, but in relation to the part.

For patients with thick thighs and buttocks (measuring greater than 24 cm), an AP projection of the knee requires a 3° to 5° caudad angulation of the central ray. This helps to minimize distortion and ensure proper visualization of the joint.

The central ray for an AP projection of the knee should be centered at the midpatella, which is the middle of the kneecap.

A true lateral projection of the knee provides the best visualization of the proximal fibula without superimposition. This means the fibula, which is located on the outer side of the leg, will be seen clearly without any other bone overlapping it.

For a lateral knee projection on a tall, slender male patient with a narrow pelvis, the central ray should be angled 5° to 10° caudad to ensure proper visualization of the knee joint. This adjustment compensates for the lack of support from the lower leg.

A recommended flexion of 20° to 30° during a lateral knee projection allows for optimal visualization of the patellofemoral joint space. This means the knee should be slightly bent to see the space between the kneecap and the thigh bone clearly.

If the distal borders of the femoral condyles (the rounded ends of the thigh bone) are not superimposed on a radiograph of a lateral knee, possible positioning errors include: 1) The knee is not truly lateral, 2) The femur is rotated internally (pointing inward), 3) The femur is rotated externally (pointing outward), 4) The leg is not parallel to the IR. These errors can lead to misinterpretations of the image.

A positioning error in an AP foot radiograph where the metatarsophalangeal joints appear closed, leading to foreshortening of the metatarsals. This indicates the foot was not fully dorsiflexed during the exposure.

A positioning error in an AP oblique-medial rotation projection of the foot where the proximal third to fifth metatarsals overlap, indicating insufficient medial rotation.

A positioning error in a plantodorsal (axial) projection of the calcaneus where the calcaneus appears shorter than it actually is, indicating the foot was not perpendicular to the IR.

The CR angle for the superoinferior sitting tangential method for the patella is 5° to 10° caudad.

A knee projection where the CR is directed from inferior to superior, often performed with the patient sitting on a wheelchair or lowered table.

A special projection of the patella requiring the patient prone with 90° knee flexion, allowing visualization of the patellofemoral joint.

A knee projection that must be taken with the patient standing upright, providing a view of the knee in weight-bearing position.

This patella view is taken with no knee flexion, utilizing a horizontal beam.

The mediolateral projection places the foot in a more natural, true lateral position, with the medial side closest to the image receptor, while the lateromedial projection places the lateral side closer to the image receptor.

A weight-bearing study, like a standing AP or a lateral projection of the foot, is recommended to best evaluate the status of the longitudinal arches.

For the plantodorsal (axial) projection of the calcaneus, the central ray should be angled 15-20 degrees cephalad from the long axis of the foot.

The sustentaculum tali should appear medially and profiled on a well-positioned plantodorsal (axial) projection of the calcaneus.

The central ray is placed perpendicular to the long axis of the calcaneus for a mediolateral projection.

The superior aspect of the ankle joint is not typically visualized with a correctly positioned AP projection of the ankle.

AP, 45° oblique, and lateral ankle radiographs should include the proximal metatarsals to assess potential injuries involving the foot, especially those involving the base of the 5th metatarsal.

For an AP mortise projection of the ankle, the foot should be internally rotated approximately 15-20 degrees so that the long axis of the foot is parallel to the image receptor.