ARRT Chapters > Chapter 14 - Lower Limb and Pelvis > Flashcards
Chapter 14 - Lower Limb and Pelvis Flashcards
foot is commonly divided into three basic parts:
the forefoot, the midfoot, and the hindfoot
The bones of the forefoot include
the phalanges and metatarsals.
The midfoot consists of
five short bones called tarsal bones
The hindfoot includes
the calcaneus and the talus
The calcaneus is commonly referred
to as the heel bone.
The talus articulates with the tibia and fibula to form
the ankle mortise
eversion
Lateral flexion of the ankle tends to roll the foot onto its medial aspect
inversion
Medial flexion causes the foot to roll onto its lateral aspect
tibia
The tibia is the longer, thicker bone on the medial side.
fibula
The fibula is much thinner and somewhat shorter and is located laterally.
medial malleolus
The medial malleolus is a bony prominence that can be palpated at the ankle on the medial aspect of the distal tibia.
lateral malleolus
The lateral malleolus is the rounded prominence on the distal aspect of the fibula and can be felt on the lateral aspect of the ankle.
knee
The distal articular surfaces of the condyles articulate with the tibial plateau to form the knee, which is a hinge-type joint.
meniscus
The articular surface of each condyle is cushioned by a C-shaped cartilage called a meniscus.
fovea capitis
A small indentation on its posterior superior surface is called the fovea capitis.
hip bones, also called the os coxae or innominate bones
The two bones that make up the halves of the pelvis. Each is a composite bone made up of three bones: the ilium, the ischium, and the pubis.
acetabulum
The ilium, ischium, and pubis join to form a synarthrodial joint at the acetabulum. The acetabulum is the rounded fossa that forms the socket of the hip joint. It articulates with the head of the femur.
Toes - AP or AP axial, AP oblique (medial rotation), and lateral projections
Body position
Seated or recumbent on table with knee flexed.
Part position
AP axial
Plantar surface supported on a 15-degree wedge sponge (Fig. 14.10).
AP
Plantar surface is in contact with IR (Fig. 14.11).
AP oblique
Medial plantar surface of toe and forefoot is in contact with IR. Plantar surface of foot and toes forms a 30- to 45-degree angle with IR (Fig. 14.13).
Lateral
Medial or lateral surface of foot may be in contact with IR, depending on which brings toe of interest nearest to IR. Other toes are flexed or extended as needed to leave affected toe free of superimposition. Affected toe is supported parallel to IR. Toes may be held in position using tape or a bandage (Fig. 14.15) or a wooden tongue blade. Positioning a single toe apart from the others often demands some creativity on the part of the radiographer. Variations may be required depending on which toe is involved, configuration of toe, and movements tolerable for the patient.
Central ray
AP axial
Angled 15 degrees posteriorly (toward heel) to MTP joints.
AP, AP oblique, and lateral
Perpendicular to MTP joints.
Structures seen
Entire digit and distal half of metatarsal with IP and MTP joint spaces open and clearly visualized (Figs. 14.12, 14.14, and 14.16).
sesamoids - tangential projection
Body position
Standing, facing away from collimator, or prone.
Part position
Plantar surface of foot resting on IR in a position of dorsiflexion, and adjusted to place the ball of the foot perpendicular to the IR (Fig. 14.17A). When the patient can’t stand, the tangential projection can be performed with the patient seated, the foot pointing up, and the plantar surface at an angle of approximately 70 degrees with the plane of the IR (Fig. 14.17B).
Central ray
Perpendicular and tangential to the first MTP joint.
Structures seen
Sesamoids and first metatarsal head in profile (Fig. 14.18).
Foot - AP axial, AP oblique (medial), and lateral projections.
Body position
Seated or recumbent on table with knee flexed. In podiatric practice, the AP (DP) and AP (DP) oblique projections are performed with the patient standing.
Part position
For all projections, foot is centered with regard to IR so that toes, heel, and both malleoli are within field.
AP axial
Plantar surface of foot is in contact with IR (Fig. 14.19).
AP oblique
Leg is rotated medially so that medial plantar aspect of foot is in contact with IR. Plantar surface of foot forms a 30-degree angle with IR (Fig. 14.21).
Lateral
Lateral aspect of foot is in contact with IR and foot is in true lateral position with plantar aspect of forefoot perpendicular to IR. Ankle is dorsiflexed so that long axis of foot is perpendicular to tibia (Fig. 14.23).
Central ray
AP axial
Angled 10 degrees posteriorly (toward heel) and entering base of third metatarsal.
AP oblique and lateral
Perpendicular to base of third metatarsal.
Structures seen
Entire foot, including toes, metatarsals, and tarsal bones. On AP axial projection, calcaneus is obscured by superimposition of lower leg (Fig. 14.20). AP oblique projection with medial rotation should demonstrate the metatarsals and some tarsals (cuboid, navicular, lateral cuneiform) with minimal superimposition on one another (Fig. 14.22). Too much superimposition of these structures indicates that angle between plantar surface of foot and IR was too great; that is, foot was everted too much. Lateral projection shows superimposition of metatarsals, more proximal than distal. It should include the ankle joint (Fig. 14.24).
Calcaneus - axial (plantodorsal) and lateral projections
Body position
Axial (plantodorsal)
Seated or recumbent on table with leg extended.
Lateral
Seated or recumbent on table with knee flexed.
Part position
Axial (plantodorsal)
Posterior surface of ankle and heel is in contact with IR. Place foot so that malleoli are centered with regard to middle of IR. Sagittal plane of foot is perpendicular to IR. Foot is dorsiflexed as much as possible and held in position by patient using a strap or bandage (Fig. 14.34).
Lateral
Lateral surface of heel is in contact with IR. Part is positioned as for lateral projection of foot but with calcaneus centered to IR (Fig. 14.36).
Central ray
Axial (plantodorsal)
Angled 40 degrees cephalad to center of IR, entering at third metatarsal base.
Lateral
Perpendicular to center of IR, entering about 1 inch (2.5cm) distal to medial malleolus.
Structures seen
Both projections demonstrate entire calcaneus and its articulation with talus (Fig. 14.35). Lateral projection also shows calcaneal articulations with cuboid and navicular anteriorly (Fig. 14.37).
Ankle - AP, AP oblique (medial rotation), AP oblique (medial rotation–mortise joint), and lateral projections.
Body position
AP and AP obliques
Seated or recumbent on table with affected leg extended.
Lateral
Recumbent or semirecumbent on affected side with knee flexed 30 to 45 degrees.
Part position
AP
Posterior surface of heel and lower leg is in contact with IR. Midpoint between malleoli is centered to IR. Foot is dorsiflexed so that plantar surface of foot forms a 90-degree angle with coronal plane of lower leg. Sagittal planes of leg and foot are perpendicular to IR (Fig. 14.39). Foot may be held in position by patient using a strap or bandage.
AP oblique (medial rotation)
From position for AP projection, entire leg is rotated medially 45 degrees. Sagittal planes of foot and leg must remain aligned to each other (Fig. 14.41).
AP oblique (medial rotation—mortise joint)
From position for AP projection, entire leg is rotated 15 to 20 degrees medially. Sagittal planes of foot and leg must remain aligned with each other (Fig. 14.43).
Lateral
Lateral surface (medial surface, if upright) of ankle is in contact with IR. Sagittal plane of foot and leg is parallel to IR. Foot is dorsiflexed so that plantar surface of foot forms a 90-degree angle with coronal plane of lower leg (Fig. 14.45).
Central ray
AP and AP obliques
Perpendicular to point midway between malleoli.
Lateral
Perpendicular to medial malleolus.
Structures seen
Superior portion of talus and distal portions of tibia and fibula (Fig. 14.40). AP oblique projection with a 45-degree medial rotation demonstrates tibiofibular joint without superimposition (Fig. 14.42). AP oblique projection with 15- to 20-degree medial rotation demonstrates mortise joint spaces without superimposition (Fig. 14.44). Lateral projection demonstrates tibiotalar and subtalar joints, and includes fifth metatarsal base (Fig. 14.46).
Lower Leg - AP and lateral projections
Body position
AP
Seated or recumbent on table.
Lateral
Recumbent on affected side with contralateral leg anterior or posterior to affected leg.
Part position
AP
Leg is fully extended with posterior surface of lower leg in contact with IR. Margin of IR is placed 1 to 2 inches beyond joint of primary interest. Foot is dorsiflexed so that plantar surface of foot forms a 90-degree angle with coronal plane of lower leg. Sagittal planes of leg and foot are perpendicular to IR (Fig. 14.50). Foot may be held in position by patient using a strap or bandage.
Lateral
Knee may be flexed, if necessary, to ensure a true lateral position. Lateral surface of lower leg is in contact with IR. Leg is rotated to place sagittal plane of leg parallel to IR and coronal plane through patella perpendicular to IR. Margin of IR is placed 1 to 2 inches beyond joint of primary interest (Fig. 14.52).
Central ray
Perpendicular to center of IR entering midshaft of tibia.
Structures seen
Entire lower leg and at least one joint (Figs. 14.51 and 14.53).
Knee - AP and lateral projections
Body position
AP
Seated or supine on table with leg extended.
Lateral
Recumbent on affected side with femur aligned with center of table. Unaffected leg is anterior or posterior to affected leg.
Part position
AP
Leg is fully extended with sagittal plane of leg perpendicular to IR (Fig. 14.54).
Lateral
Knee is flexed 20 to 30 degrees. Sagittal plane of femur and lower leg is parallel to IR (Fig. 14.56).
Central ray
AP
Entering 0.5 inch distal to apex of patella. Angle is variable, depending on the measurement between the ASIS and the tabletop, as follows:
<19cm (thin patient)
19 to 24cm
> 24cm (large pelvis)
3 to 5 degrees caudad
0 degrees (perpendicular)
3 to 5 degrees cephalad
Lateral
Angled 5 to 7 degrees cephalad entering 1 inch distal to medial epicondyle of femur.
Structures seen
Knee joint with portions of distal femur and proximal lower leg (Fig. 14.55). Lateral projection includes a profile of tibial tuberosity. It should demonstrate distal femur with condyles superimposed and joint space free of superimposition. Entire patella and retropatellar joint space should also be clearly visualized (Fig. 14.57).
Knee - Pa Axial Projection—Holmblad Method
Body and part position
Patient is on hands and knees on radiographic table with affected knee flexed so that angle between femur and table is 70 degrees. Contralateral knee is flexed more and is forward to provide support (Fig. 14.60). Pelvis must remain level and sagittal plane of affected leg must remain perpendicular to the IR.
Central ray
Perpendicular to center of IR through center of knee joint.
Structures seen
Knee joint with portions of distal femur and proximal lower leg. Open intercondylar fossa (Fig. 14.61).
Knee - Pa Axial Projection—Camp-Coventry Method
Body and part position
Prone with affected knee flexed to form an angle of 40 or 50 degrees between tibia and table (Fig. 14.62).
Central ray
Angled 40 degrees caudad through knee joint to center of IR if leg is 40 degrees, and 50 degrees if leg is 50 degrees.
Structures seen
Knee joint with portions of distal femur and proximal lower leg. Open intercondylar fossa (Fig. 14.63).
Knee - Tangential (“Sunrise”) Projection of The Patella—Settegast Method
Position
Prone with affected knee flexed as much as possible or until the patella is perpendicular to the IR. Sagittal plane of femur is perpendicular to IR. Position may be supported by a strap around the ankle that is extended over patient’s shoulder and held by patient (Fig. 14.64). Alternatively, patient may be seated on the radiographic table (Fig. 14.65).
Central ray
Angled 15 to 20 degrees cephalad and centered to inferior margin of patella. Angulation is adjusted so that central ray passes between patella and distal femur.
Structures seen
Patella in profile and open patellofemoral joint (Fig. 14.66).
Distal Femur - AP and lateral projections
Body position
AP
Supine with affected femur aligned with center of table.
Lateral
Recumbent on affected side with affected femur aligned with center of table. Knee and hip of unaffected limb are flexed, and leg is supported anterior to the body.
Part position
AP
Leg is extended with sagittal plane perpendicular to IR. Ensure plane through epicondyles is parallel with IR. Inferior margin of IR is placed 1 to 2 inches below knee joint (Fig. 14.67).
Lateral
Knee of affected leg is flexed 30 to 45 degrees. Sagittal plane of femur is parallel to IR. Inferior margin of IR is placed 1 to 2 inches below knee joint (Fig. 14.69).
Central ray
Perpendicular to midpoint of IR.
Structures seen
Knee joint and distal three-fourths of femur (Figs. 14.68 and 14.70).
Proximal Femur - AP and lateral projections
Body position
AP
Supine with affected femur aligned to center of table.
Lateral
Recumbent in oblique position on affected side with support under unaffected hip. Affected femur aligned to center of table. Knee and hip of unaffected limb are flexed and leg is supported posterior to body.
Part position
AP
Leg is extended with sagittal plane perpendicular to IR. Rotate the limb internally 10 to 15 degrees to place the femoral neck in profile. Superior margin of IR is placed at level of ASIS (Fig. 14.71).
Lateral
Rotate pelvis posteriorly 10 to 15 degrees from lateral position to prevent superimposition. Sagittal plane of femur is parallel to IR as much as possible. Superior margin of IR is placed at level of ASIS (Fig. 14.73).
Central ray
Perpendicular to midpoint of IR.
Structures seen
Hip joint and proximal three-fourths of femur (Figs. 14.72 and 14.74).
Pelvis - AP projection
Body position
Supine on table. Coronal plane of body is parallel to IR (Fig. 14.75). If there is no suspicion of recent fracture, femurs are rotated medially 15 to 20 degrees to place femoral necks parallel to IR. The heels will be 8 to 10 inches apart (Fig. 14.76).
IR placement
Center IR midway between ASIS and pubic symphysis.
Central ray
Perpendicular to midpoint of IR.
Structures seen
Entire pelvis and proximal portion of femurs (Fig. 14.77).
Hip - AP and lateral projections
Body position
Supine on table.
Part position
AP
Femur is medially rotated 15 degrees as for pelvis (Fig. 14.79).
Lateral (“frog-leg” position)
Hip is flexed as much as possible and femur abducted 45 degrees. If patient cannot abduct femur sufficiently from supine position, pelvis may be rotated toward affected side (Fig. 14.81).
Central ray
Perpendicular to midfemoral neck.
Structures seen
Proximal fourth of femur, acetabulum, and portion of pelvis surrounding acetabulum (Figs. 14.80 and 14.82).
Stress fractures
Stress fractures are most commonly seen in the feet, the result of stress to a bone from repeated injuries that would not cause fractures if they occurred only once.
bimalleolar fracture
The associated fibular fracture may be in the same general region as the tibial fracture.
hip fractures
Fractures of the proximal femur (head, neck, and intertrochanteric region)
Gouty arthritis
Gouty arthritis is a joint condition caused by gout, a systemic disorder that increases the uric acid content of the blood. Gouty arthritis commonly affects the feet, particularly the joints of the great toe (Fig. 14.91), although it may also involve the hands.
Osteoarthritis
Osteoarthritis may cause degeneration of any of the joints of the lower limb but is most common in the knee and the hip (Fig. 14.92).
osteogenic sarcoma
one of several types of malignant bone tumors that occur in the lower limb.
