RADPOS - Trigger 9

• Axial – Plantodorsal

• Axial – Dorsoplantar

• Weight-Bearing Coalition Method

• Lateral – Mediolateral

• Lateromedial Oblique (Weight-Bearing Method)

(5) Calcaneus Projections

Axial – Plantodorsal of Calcaneus

Patient Position

• Place the patient in the supine or seated position with the legs fully extended.

Part Position

• Place the IR under the patient's ankle, centered to the midline of the ankle.

• Place a long strip of gauze around the ball of the foot. Have the patient grasp the gauze to hold the ankle in right angle dorsiflexion.

Central ray

• Directed to the midpoint of the IR at a cephalic angle of 40 degrees to the long axis of the foot.

• The central ray enters the base of the third metatarsal.

Structures Shown

• The resulting image shows an axial projection of the calcaneus

Supine or seated, legs fully extended

What is the patient position in Axial Projection – Plantodorsal (Calcaneus)?

Under ankle, centered to midline

Where is the IR placed in Axial Projection – Plantodorsal (Calcaneus)?

Gauze around ball of foot, patient pulls

How is the ankle held in right angle dorsiflexion in Axial Projection – Plantodorsal (Calcaneus)?

40° cephalic to long axis of foot

What is the CR angle in Axial Projection – Plantodorsal (Calcaneus)?

Base of 3rd MT

Where does the CR enter in Axial Projection – Plantodorsal (Calcaneus)?

Calcaneus

What structure is shown in Axial Projection – Plantodorsal (Calcaneus)?

Axial – Dorsoplantar of Calcaneus

Patient Position

• Place the patient in the prone position.

Part Position

• Elevate the patient's ankle on sandbags.

• Adjust the height and position of the sandbags under the ankle in such a way that the patient can dorsiflex the ankle enough to place the long axis of the foot perpendicular to the tabletop.

• Place the IR against the plantar surface of the foot.

Central ray

• Directed to the midpoint of the IR at a caudal angle of 40 degrees to the long axis of the foot.

• The central ray enters the dorsal surface of the ankle joint.

Structures Shown

• The resulting image shows an axial projection of the calcaneus and the subtalar joint

Prone

What is the patient position in Axial Projection – Dorsoplantar (Calcaneus)?

Elevated on sandbags

How is the ankle supported in Axial Projection – Dorsoplantar (Calcaneus)?

Long axis perpendicular to tabletop

How is the foot positioned in Axial Projection – Dorsoplantar (Calcaneus)?

Against plantar surface of foot

Where is the IR placed in Axial Projection – Dorsoplantar (Calcaneus)?

40° caudal to long axis of foot

What is the CR angle in Axial Projection – Dorsoplantar (Calcaneus)?

Dorsal surface of ankle joint

Where does the CR enter in Axial Projection – Dorsoplantar (Calcaneus)?

• Calcaneus

• subtalar joint

What structures are shown in Axial Projection – Dorsoplantar (Calcaneus)?

Weight-Bearing Coalition Method of Calcaneus

This method, described by Lilienfeld (cit. Holzknecht), has come into use for the demonstration of calcaneotalar coalition. For this reason, it has been called the "coalition position."

Patient Position

• Place the patient in the standing-upright position.

Part Position

• Center the IR to the long axis of the calcaneus, with the posterior surface of the heel at the edge of the IR.

• To prevent superimposition of the leg shadow, have the patient place the opposite foot one step forward

Central ray

• Angled exactly 45 degrees anteriorly and directed through the posterior surface of the flexed ankle to a point on the plantar surface at the level of the base of the fifth metatarsal

Demonstration of calcaneotalar coalition

What is the purpose of the Weight-Bearing “Coalition Method”?

Standing upright

What is the patient position in the Coalition Method?

Long axis of calcaneus

How is the IR centered in the Coalition Method?

At the edge of the IR

Where is the posterior surface of the heel positioned in relation to the IR?

Opposite foot placed one step forward

How is superimposition of the leg shadow prevented in the Coalition Method?

45° anterior

What is the CR angle in the Coalition Method?

Through posterior surface of flexed ankle to plantar surface at base of 5th metatarsal

Where is the CR directed in the Coalition Method?

Lateral – Mediolateral of Calcaneus

Patient Position

• Have the supine patient turn toward the affected side until the leg is approximately lateral. A support may be placed under the knee.

Part Position

• Adjust the calcaneus to the center of the IR.

• Adjust the IR so that the long axis is parallel with the plantar surface of the heel.

Central ray

• Perpendicular to the calcaneus. Center about 1 inch (2.5 cm) distal to the medial malleolus. This will place the CR at the subtalar joint.

Structures Shown

• The resulting radiograph shows the ankle joint and the calcaneus in lateral profile.

• Supine

• turned toward affected side

What is the patient position in Lateral (Mediolateral) Calcaneus?

Centered

How is the calcaneus positioned on the IR?

Long axis parallel with plantar surface

How should the IR be adjusted relative to the heel?

Perpendicular to calcaneus

What is the CR direction for Lateral Calcaneus?

1 inch distal to medial malleolus

Where is the CR centered in Lateral Calcaneus?

Subtalar joint

What joint does this CR placement correspond to?

• Ankle joint

• calcaneus in lateral profile

What structures are shown in Lateral Calcaneus?

Lateromedial Oblique (Weight-Bearing Method) of Calcaneus

Patient Position

• Have the patient stand with the affected heel centered toward the lateral border of the IR.

Part Position

• Adjust the patient's leg to ensure that it is exactly perpendicular.

• Center the calcaneus so that it will be projected to the center of the IR.

• Center the lateral malleolus to the midline axis of the IR.

Central ray

• Directed medially at a caudal angle of 45 degrees to enter the lateral malleolus.

Structures Shown

• The resulting image shows the calcaneal tuberosity and is useful in diagnosing stress fractures of the calcaneus or tuberosity

Standing, affected heel centered to lateral border of IR

What is the patient position in Lateromedial Oblique Calcaneus (Weight-Bearing)?

Leg perpendicular

How should the leg be adjusted in Lateromedial Oblique Calcaneus?

Center of IR

How should the calcaneus be centered in Lateromedial Oblique Calcaneus?

Lateral malleolus

What landmark is centered to the IR midline axis in Lateromedial Oblique Calcaneus?

Medially, 45° caudal angle

What is the CR direction in Lateromedial Oblique Calcaneus?

Lateral malleolus

Where does the CR enter in Lateromedial Oblique Calcaneus?

Calcaneal tuberosity

What structures are shown in Lateromedial Oblique Calcaneus?

• AP Axial Oblique (Broden Method) – Medial rotation

• AP Axial Oblique (Broden Method) – Lateral rotation of foot

• Lateromedial Oblique (Isherwood Method) – Medial rotation foot

• AP Axial Oblique (Isherwood Method) – Medial rotation ankle

• AP Axial Oblique (Isherwood Method) – Lateral rotation ankle

(5) Subtalar Joint Projections

AP Axial Oblique (Broden Method) – Medial rotation

Broden recommended the lateromedial and mediolateral right-angle oblique projection for demonstration of the posterior articular facet of the calcaneus to determine the presence of joint involvement in cases of comminuted fracture.

Patient Position

• Place the patient in the supine position.

• Adjust a small sandbag under each knee.

Part Position

• Place the IR under the patient's lower leg and heel with its midline parallel with and centered to the leg.

• Adjust the IR so that the lower edge is about 1 inch (2.5 cm) distal to the plantar surface of the heel.

• Loop a strip of bandage around the ball of the foot. Have dorsiflex the foot enough to obtain right-angle flexion at the ankle joint.

• With patient's ankle joint maintained in right-angle flexion, rotate the leg and foot 45 degrees medially, and rest the foot against a 45-degree foam wedge.

Central ray

• Angled cephalad at 40, 30, 20, and 10 degrees, respectively. Four separate images are obtained

• For each image, direct the central ray to a point 2 or 3 cm caudoanteriorly to the lateral malleolus, to the midpoint of an imaginary line extending between the most prominent point of the lateral malleolus and the base of the fifth metatarsal.

Structures Shown

• The anterior portion of the posterior facet is shown best in the 40-degree projection. The 10-degree projection shows the posterior portion. The articulation between the talus and

  sustentaculum tali (middle facet) is usually shown best in one of the intermediate projections.

AP Axial Oblique (Broden Method) – Medial rotation

What projection is used to demonstrate the posterior articular facet of the calcaneus in comminuted fractures?

Supine

What is the patient position in AP Axial Oblique Calcaneus (Broden Method)?

Small sandbag

What support is placed under each knee in AP Axial Oblique Calcaneus?

Under lower leg and heel, midline parallel and centered to leg

How is the IR positioned in AP Axial Oblique Calcaneus?

1 inch distal to plantar surface of heel

Where is the lower edge of the IR placed in AP Axial Oblique Calcaneus?

Bandage strip

What tool is looped around the ball of the foot in AP Axial Oblique Calcaneus?

Right-angle flexion (90°)

How is the ankle joint positioned in AP Axial Oblique Calcaneus?

45° medially, resting on foam wedge

How is the leg and foot rotated in AP Axial Oblique Calcaneus?

40°, 30°, 20°, 10° cephalad

What are the CR angulations for AP Axial Oblique Calcaneus?

2–3 cm caudoanterior to lateral malleolus (midpoint between lateral malleolus and base of 5th metatarsal)

Where is the CR directed in AP Axial Oblique Calcaneus?

40°

Which CR angle best shows the anterior portion of the posterior facet?

10°

Which CR angle best shows the posterior portion of the posterior facet?

Talus–sustentaculum tali articulation (middle facet)

What structure is shown best in intermediate projections (20–30°)?

AP Axial Oblique (Broden Method) – Lateral rotation of foot

Patient Position

• Place the patient in the supine position.

• Adjust a small sandbag under each knee.

Part Position

• With the patient's ankle joint held in right-angle flexion, rotate the leg and foot 45 degrees laterally. The foot may rest against a 45-degree foam wedge.

Central ray

• Directed to a point 2 cm distal and 2 cm anterior to the medial malleolus, at a cephalic angle of 15 degrees for the first exposure.

• Two or three images may be made with a 3- or 4-degree difference in central ray angulation

Structures Shown

• The posterior facet of the calcaneus is shown in profile. The articulation between the talus and sustentaculum tali is usually shown.

AP Axial Oblique (Broden Method) – Lateral rotation of foot

What projection is used with lateral rotation of the foot to show the posterior facet of the calcaneus?

Supine

What is the patient position in AP Axial Oblique Calcaneus (Lateral Rotation)?

Small sandbag

What support is placed under each knee in AP Axial Oblique Calcaneus (Lateral Rotation)?

Right-angle flexion (90°)

How is the ankle joint positioned in AP Axial Oblique Calcaneus (Lateral Rotation)?

45° laterally

How is the leg and foot rotated in AP Axial Oblique Calcaneus (Lateral Rotation)?

45° foam wedge

What support may the foot rest against in AP Axial Oblique Calcaneus (Lateral Rotation)?

15° cephalad

What is the CR angulation for the first exposure in AP Axial Oblique Calcaneus (Lateral Rotation)?

2 cm distal and 2 cm anterior to medial malleolus

Where is the CR directed in AP Axial Oblique Calcaneus (Lateral Rotation)?

2–3 images

How many images may be taken in AP Axial Oblique Calcaneus (Lateral Rotation)?

3–4°

What difference in CR angulation is used for successive images?

Posterior facet of calcaneus

What structure is shown in profile in AP Axial Oblique Calcaneus (Lateral Rotation)?

Talus–sustentaculum tali

What articulation is usually shown in AP Axial Oblique Calcaneus (Lateral Rotation)?

Lateromedial Oblique (Isherwood Method) – Medial rotation foot

Isherwood devised a method for each of the three separate articulations of the subtalar joint:

• (1) a medial rotation foot position for the demonstration of the anterior talar articular surface,

• (2) a medial rotation ankle position for the middle talar articular surface, and

• (3) a lateral rotation ankle position for the posterior talar articular surface.

Patient Position

• Place the patient in a semi supine or seated position, turned away from the side being examined

• Ask the patient to flex the knee enough to place the ankle joint in nearly right-angle flexion and then to lean the leg and foot medially.

Part Position

• With the medial border of the foot resting on the IR, place a 45-degree foam wedge under the elevated leg.

• Adjust the foot to be at a right angle. Place a support under the knee.

Central ray

• Perpendicular to a point 1 inch (2.5 cm) distal and 1 inch (2.5 cm) anterior to the lateral malleolus

Structures Shown

• The resulting image shows the anterior subtalar articular surface and an oblique projection of the tarsals.

Lateromedial Oblique (Isherwood Method) – Medial rotation foot

What projection is used to demonstrate the anterior talar articular surface of the subtalar joint?

Isherwood

Who devised the method for subtalar joint articulations?

3

How many positions are included in Isherwood’s method for subtalar articulations?

Anterior talar articular surface

Which articulation is shown with medial rotation of the foot in Isherwood’s method?

Semisupine or seated, turned away from examined side

What is the patient position in Isherwood Medial Rotation Foot?

Flexed enough for nearly right-angle flexion of the ankle

How should the knee be positioned in Isherwood Medial Rotation Foot?

Leaned medially

How is the leg and foot adjusted in Isherwood Medial Rotation Foot?

Medial border

What part of the foot rests on the IR in Isherwood Medial Rotation Foot?

45° foam wedge

What support is placed under the elevated leg in Isherwood Medial Rotation Foot?

right angle

How should the foot be positioned in relation to the leg in Isherwood Medial Rotation Foot?

1 inch distal and 1 inch anterior to lateral malleolus

Where is the CR directed in Isherwood Medial Rotation Foot?

Anterior subtalar articular surface

What structure is shown in Isherwood Medial Rotation Foot?

Oblique projection of the tarsals

Besides the anterior subtalar surface, what else is demonstrated in Isherwood Medial Rotation Foot?

AP Axial Oblique (Isherwood Method) – Medial rotation ankle

Patient Position

• Have the patient assume a seated position on the radiographic table and turn with body weight resting on the flexed hip and thigh of the unaffected side.

• If a semi lateral recumbent position is more comfortable, adjust the patient accordingly.

Part Position

• Ask the patient to rotate the leg and foot medially enough to rest the side of the foot and affected ankle on an optional 30-degree foam wedge.

• Place a support under the knee. If the patient is recumbent, place another under the greater trochanter

• Dorsiflex the foot, then invert it if possible, and have the patient maintain the position by pulling on a strip of 2- or 3- inch (5- to 7.6-cm) bandage looped around the ball of the foot.

Central ray

• Directed to a point 1 inch (2.5 cm) distal and 1 inch (2.5 cm) anterior to the lateral malleolus at an angle of 10 degrees cephalad.

Structures Shown

• The resulting image shows the middle articulation of the subtalar joint and an "end-on" projection of the sinus tarsi

AP Axial Oblique (Isherwood Method) – Medial rotation ankle

What projection demonstrates the middle articulation of the subtalar joint?

Seated (or semi lateral recumbent)

What patient position is used in Isherwood Medial Rotation Ankle?

Unaffected side (on flexed hip and thigh)

On which side should the patient rest their body weight in Isherwood Medial Rotation Ankle?

Medially

How is the leg and foot rotated in Isherwood Medial Rotation Ankle?

30° foam wedge

What support is used under the foot and ankle in Isherwood Medial Rotation Ankle?

Dorsiflexed and inverted

What additional positioning is done to the foot in Isherwood Medial Rotation Ankle?

Bandage loop around ball of foot, pulled by patient

How is the foot held in position during Isherwood Medial Rotation Ankle?

1 inch distal and 1 inch anterior to lateral malleolus

Where is the CR directed in Isherwood Medial Rotation Ankle?

10° cephalad

What CR angle is used in Isherwood Medial Rotation Ankle?

• Middle subtalar articulation

• end-on sinus tarsi

What structures are shown in Isherwood Medial Rotation Ankle?

AP Axial Oblique (Isherwood Method) – Lateral rotation ankle

Patient Position

• Place the patient in the supine or seated position.

Part Position

• Ask the patient to rotate the leg and foot laterally until the side of the foot and ankle rests against an optional 30-degree foam wedge.

• Dorsiflex the foot, evert it if possible, and have the patient maintain the position by pulling on a broad bandage looped around the ball of the foot.

Central ray

• Directed to a point 1 inch (2.5 cm) distal to the medial malleolus at an angle of 10 degrees cephalad

Structures Shown

• The resulting image shows the posterior articulation of the subtalar joint in profile

AP Axial Oblique (Isherwood Method) – Lateral rotation ankle

What projection demonstrates the posterior articulation of the subtalar joint in profile?

Supine or seated

What is the patient position for Isherwood Lateral Rotation Ankle?

Laterally

How is the leg and foot rotated in Isherwood Lateral Rotation Ankle?

30° foam wedge

What support is used under the foot and ankle in Isherwood Lateral Rotation Ankle?

Dorsiflexed and everted

How is the foot positioned in Isherwood Lateral Rotation Ankle?

Broad bandage loop around ball of foot, pulled by patient

How is the foot maintained in position during Isherwood Lateral Rotation Ankle?