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Radiology Clinical III~~~

Lower Extremity ~~~~~

Image Review

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The following information is only a personal suggested guideline to follow when

positioning Lower Extremity exams.

For additional information on positioning of these

exams, please reference your Radiographic

Positioning and Related Anatomy Textbook.

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AP Toe• SID 40” / TT • CR < 10° -15°

towards calcaneusor ┴ to the phalanges

• CP to effected digit at the MTP jt

• Collimate• Shield

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Oblique Toes(s)• SID 40” / TT • Rotate foot 30°-45°

either medially or laterally

• CR ┴ to IR• CP to effected digit

at the MTP jt• Collimate• Shield

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Lateral Toe• SID 40” / TT • Foot on medial surface for

1st 2nd & 3rd digits, and lateral surface for 4th & 5th digits. (Use tape, tongue blades & gauze)

• CR ⏊ to IR• CP to effected digit at the

MTP jt• Collimate• Shield

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AP Toes

Repeatable error:

Good Image

Positioningor CR Angle

*Toes need to be parallel to the IR, put toes on a sponge or angle CR

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Toes

Pathology

ArthritisOr

Osteomyelitis

Good Image

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AP Foot• SID 40” / TT • Planter surface of foot

on IR w/ toes extended• CR < 10° towards

calcaneusor ⏊ to the metatarsals

• CP to the base of the 3rd MTP jt

• Collimate• Shield

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High Arch

CR 10°<

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Flat ArchCR-5°<

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AP Foot

Repeatable error:

Good Image

Collimation/CR

*Or patient’s foot slid forward on the IR

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AP Foot

Repeatable error:

Good Image

Collimation/CR*Or patient moved their foot. *Also remember to place part with long axis of IR

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FootPathology

Arthritis, Osteomyelitis

or Gout1st MTP Jt.

Good Image

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Foot

Pathology

MVAdecapitation of foot from

tib-fib

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Foot

Pathology

Polydactyly

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Foot

Pathology

TraumaWith

reconstruction

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Oblique Foot• SID 40” / TT

• Planter surface of foot on IR w/ toes extended

• Rotate foot medially 30°-40°

• CR ┴ to IR• CP to the base of the

3rd MTP jt• Collimate• Shield

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Foot

Pathology

Arthritis, Osteomyelitis

or Gout1st MTP Jt.

Good Image

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Foot

Pathology

Surgical fixation

Phalanges

*image was shot standing

with angled CR Good Image

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Lateral Foot

• SID 40” / TT • Place foot on lateral

surface• Dorsiflex foot and

ensure plantar surface of foot is ┴ to IR

• CR ┴ to IR• CP to medial

cuneiform• Collimate• Shield

Good Image

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LateralFoot

Repeatable error:

Positioning

Good Image

Good Image

*over rotated

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Foot

Pathology

*foot infection with gangrene

causing subcutaneous gas within the

tissues

Good Image

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Plantodorsal Axial Calcaneus• SID 40”/ TT

• Pt. supine on table, legs fully extended• Dorsiflex foot to put plantar surface of foot ⏊ to IR• CR < 40° cephalad (or ⏊ to long axis of calcaneus)• CP to the base of the 3rd

metatarsal• Collimate • Shield

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Axial HeelRepeatableerror:

Good Image

Positioningor CR Angle error

*not enough dorsiflex or not enough CR angle

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Axial HeelRepeatableerror:

Good Image

Positioningor CR Angle error

*too much dorsiflex or too muchCR angle

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Lateral Calcaneus• SID 40” / TT • Place foot on lateral

surface• Dorsiflex foot and ensure

plantar surface of foot is ⏊ to IR (true lateral)

• CR ⏊ to IR• CP 1” inferior to medial

malleolus• Collimate• Shield

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Lateral HeelRepeatableerror:

Good Image

Positioning

*RotationThe leg is under rotated. The knee should be closer to the IR, and the foot should be dorsiflexed.

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Heel

Pathology

Bone cyst within the calcaneus

followed by bone graft

implant

Good Image

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AP Ankle• SID 40”/ TT• Pt. supine on table,

legs fully extended• Adjust foot (slight

dorsiflexion) to acquire true AP projection

• CR ⏊ to IR• CP to a point midway

between malleoli• Collimate• Shield

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AnklePathology

Rheumatoid ArthritisAnd/or congenital abnormalities, with ankle replacement surgery

Good Image

32Good Image

Ankle

Pathology

Trauma

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Ankle

Pathology

Trauma

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Ankle

Pathology

Trauma

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3 4

1 2

Chose the best positioning

APMortise

View

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3 4

1 2

Best positioning

APMortise

View

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AP Mortise Ankle• SID 40”/ TT• Pt. supine on table,

legs fully extended• Rotate entire leg

medially 15°-20°until intermalleolar line is ∥ to IR

• CR ⏊ to IR• CP midway

between malleoli• Collimate• Shield

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AP 15°-20° Oblique (Mortise) 45° Oblique

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AP MortiseAnkle

Repeatableerror:

Good Image

Positioning*do not let foot droop causing the fibula to be superimposed onto the calcaneus.

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Lateral Ankle

Choose the best

positioning.

1

3

2

4

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Lateral Ankle

Best positioning.

1

3

2

4

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Lateral Ankle

• SID 40” / TT • Place foot on lateral

surface• Dorsiflex foot so

plantar surface is at a right angle to the leg

• CR ⏊ to IR• CP to medial malleolus• Collimate• Shield

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LateralAnkleRepeatableerror: Positioning*Foot has too much droop. It needs to be dorsiflexed to put foot in true lateral position. Good Image

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LateralAnkleRepeatableerror:

Good Image

Positioning*RotationThe leg is under rotated. The knee should be closer to the table , and the foot should be dorsiflexed.

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LateralAnkleRepeatableerror:

Good Image

Positioning*RotationThe leg is over rotated. The knee is too close to the table, and the foot should be dorsiflexed.

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AnklePathology

Rheumatoid ArthritisAnd/or congenital abnormalities

Good Image

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Ankle

Pathology

Trauma

Good Image

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AP Tib-Fib• SID 40”/ TT• Pt. supine on table,

legs fully extended• Dorsiflex foot to

acquire true AP projection

• CR ⏊ to IR• CP to midpoint of leg• Collimate• Shield

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Lateral Tib-Fib• SID 40” / TT

• Flex knee 45° and place leg on lateral surface. Ensure both ankle & knee joints are on image

• Dorsiflex foot so plantar surface is at a right angle to the leg

• CR ⏊ to IR• CP to midleg• Collimate• Shield

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Tib-FibRepeatable Error:Exposure

*Make sure you keep track of which IR plates have already been exposed!

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Tib-Fib

Pathology

Osteogenesis Imperfecta

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Tib-Fib

Pathology

Osteosarcoma

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AP Knee• SID 40”/ TT• Pt. supine on table, legs

fully extended• Rotate leg 3°-5° for true AP• CR ║ with the tibial plateau

(3°-5° caudad for thin buttocks; 0° for average buttocks; 3°-5° cephalad for thick buttocks)

• CP to ½” distal to apex of patella

• Collimate• Shield

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CR guideline - AP Knee

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KneeRepeatable Error:

Good Image

Exposure

*ensure appropriate technique correlate's with grid.

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Good Image

Positioning

*the leg is rotated laterally. From True anatomical position, It should be rotated 3°-5° medially.

KneeRepeatable Error:

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Knee

Pathology

Surgical fixation of a fractured patella Good Image

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Good Image

Knee

Pathology

Arthritis

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Good Image

Knee

Pathology

Bone lesion

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Good Image

Knee

Pathology

Trauma

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Good Image

Knee

Pathology

Bone lesion

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Knee

Pathology

Bone Lesion Cancerous

With MRI & Nuc Med scans

Good Image

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Good Image

Knee

Pathology

Trauma

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Knee

Pathology

Impaction fracture

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Lateral Knee• SID 40” / TT • Flex knee 20°-30° and

place leg on lateral surface in true lateral position.

• CR 5°-7° cephalad (5° for narrow pelvis and 7°-10°for wide pelvis)

• CP 1” distal to medial epicondyle

• Collimate• Shield

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Lateral Knee•Knee should be flexed 20-30 degrees•Angle CR appropriately or put entire leg parallel with the IR-get eye level to the leg.•Standing-check dimples

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Positioning Error for mediolateral Lateral Knee:

Good Image

Too much of the proximal fibula is superimposed with the tibia. The knee is under rotated or too far away from the image receptor.

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The fibula head is too far posterior. The knee is over rotated or too far towards the image receptor

Good Image

Positioning Error for mediolateral Lateral Knee:

*This is opposite for Lateromedial Laterals (XTL)

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Knee

Pathology

Bone lesion

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Knee

Pathology

Bone growth abnormality

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19 18

24 15

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2122

Anatomy

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Axial Intercondylar fossa (Tunnel view)Acronym:*Mr. Beclere & Rose went Hom(blad) to Camp Coventry

1. Beclere-AP2. Rosenberg-PA3. Homblad-PA4. Camp Coventry-PA

*For all views-the CR is ⏊ to Tib-Fib

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Rosenberg

Repeatableerror:

Positioning

*Ensure that the shield does not hang

down to interfere with the AEC.

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Tangential (Axial or Sunrise) PatellaAcronym *MISS HH

1. Merchant2. InferoSuperior3. Settegast4. Hughston5. Hobbs * For all views, the goal is to match the CR angle with the knee flexion angle.

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SunrisePatella

Repeatableerror:

Good Image

shoe

Positioning

*Ensure shoe/foot

is not in the way of

the CR

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SunrisePatella

Repeatableerror:

Good Image

Positioning

*Be sure to feel for the base

and the apex of the patella

when centering

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AP Femur• SID 40”/ Bucky• Pt. supine on table, leg fully

extended• Verbally ask patient to

internally rotate their leg 5° for distal femur & 15° for proximal femur, do not force!

• Ensure both joints are included on image

• CR ┴ to IR • CP to mid femur• Collimate• Shield

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Lateral Femur• SID 40”/ Bucky

• Pt. supine on table, leg fully extended

• Flex knee 45° with lateral thigh on table

• Ensure both joints are included on image

• CR ┴ to IR • CP to mid femur• Collimate• Shield

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Femur

Pathology

Bone growth from previous fracture site

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Femur

Pathology

?

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Femur

Pathology

Trauma after total knee surgery. Also see previously fractured femur at mid shaft which is now healed.

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Femur

Pathology

Trauma*take note of how different bones look in two views at right angles to each other.

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Femur

Pathology

Trauma*Femur plate snapped in half. Question pathological fracture.

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AP Hip• SID 40”/ Bucky• Pt. supine on table, legs

fully extended• Verbally ask patient to

internally rotate their leg 15°-20°, do not force!

• CR ┴ to IR • CP 1”-2” distal to mid

femoral neck• Collimate• Shield“clinical trick” - the “crease” of the leg within the groin is where the femoral neck is located.

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AP Hip

Repeatableerror:

Centering

*Know your positioning

Landmarks. If you cannot feel them due

to body habitus, ask the patient to show you where their crest is.

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AP Hip

Repeatableerror:

Centering

*Feel for patient’s crest and/or ASISDo not assume the crease will work!

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AP Hip

Repeatableerror:

Positioning

*Artifact-hand.Pay attention to

where your patient’s hands are!

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Hip

Pathology

TraumaFractured femoral neck, most common after falls.

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Hip

Pathology

TraumaFemoral head dislocation

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Frog Hip - Modified Cleaves Method• SID 40”/ Bucky• Pt. supine on

table, legs fully extended

• Abduct femur 45° from vertical

• CR ┴ to IR • CP to mid femoral

neck• Collimate• Shield

What alternate view can you do if the patient cannot abduct their leg?

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Frog Hip

Repeatableerror:

Centering

*Know your positioning

Landmarks. If you cannot feel them due to body habitus, ask the patient to show

you where their crest is.

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Frog Hip

Repeatableerror:

Centering

*Know your positioning

landmarks.

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Axiolateral Inferosuperior HipDanelius-Miller Method

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XTL Hip

Repeatableerror:

Place marker along this area of the IR

Structures shown

& Markers

*Careful of your marker placement

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XTL Hip

Repeatableerror:

Structures shown &

Collimation/CR

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XTL Hip

Repeatableerror:

Technical/Positioning

*either the cassette was not below the table line,

or the Tech did not realize the anatomy would sink into the

stretcher or bed.

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Modified Axiolateral HipClements-Nakayama Method

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AP Pelvis• SID 40”/ Bucky• Pt. supine on table, legs

fully extended• Verbally ask patient

to internally rotate the long axes of the feet and lower legs 15°-20°, do not force!

• CR ┴ to IR • CP ½ way between the

ASIS & symphysis pubis.• Collimate“clinical trick” – Place the top of the IR just slightly above the crest, then center the CR to the IR.

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AP PelvisFemale shielding

Bilat HipsMale shielding

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APPelvis

Repeatableerror:

Positioning

*Artifact-Snaps on

gown

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APPelvis

Repeatableerror:

Positioning

*Artifact-handKnow

where your patient’s hands

are!

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APPelvis

Repeatableerror:

Positioning

*Artifact –hands. Often patient’s will

tuck their hands under their hips

because the table is so hard.

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APPelvis

Repeatableerror:

Positioning

*additional questions need to be asked of

patient… “Do you have any

buttons, snaps, trinkets or charms on your

underwear?”

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APPelvis

Repeatableerror:

Centering

*Centering is too low, know

your landmarks

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Hip

Pathology

Paget’s Diseaseto left superior pubic rami and ischium

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Hip

Pathology

Multiple Myeloma.Several lytic lesion throughout pelvis.

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AP Pelvis

Pathology

TraumaFemoral

head dislocation

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AP Pelvis

Pathology

TraumaFemoral

head dislocation

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APPelvis

Pathology

TraumaFemoral

neck fracture

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APPelvis

Repeatableerror:

Positioning

*Artifacts - before shooting the image through the trauma bed, you should try

remove all metal that is on the patient.

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Patient is pregnant - The fetal head is in the pelvis

AP Pelvis

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AP Axial “Inlet” Pelvis

This view shows superimposition of the pubic rami and ischium, which can best display anterior or posterior

displacement of those bones.

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Pelvis

Pathology

TraumaFracture of the left pubic rami and ischium.

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AP Axial “Outlet” Pelvis

This view shows a true AP view of the pubic rami and ischium, which can best display superior or inferior

displacement of those bones.

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Judet Views Pelvis

Oblique views of the hips/pelvis. Side up shows the rims of the acetabulum opened and side down shows it in

profile.

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Judet Pelvis

Pathology

TraumaFracture of the of the left acetabulum

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Leg Lengths

Exam done supine or standing to show leg length discrepancy.3 separate coned exposures were made onto one IR.

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~The End~