RADIOGRAPHY OF THE ANKLE and LOWER LEG

RADIOGRAPHY OF THE ANKLE and LOWER LEG

Patient Position: ANKLE AP Projection Part Position: True Slight to place foot s long axis Center to

Central Ray: to IR Midway Note: Ankle joint is to tips of malleoli

Structures Shown

AP Ankle Criteria for Evaluation The long axis of the leg should be in alignment. The tibia should be slightly joint should be open. Medial mortise should. Talus should be slightly The foot should be

AP ankle Error ankle, too much of the is superimposed on the and the tibiotalar joint. The leg is slightly rotated. Correction: rotate slightly to place the leg in.

ANKLE AP Mortise Oblique Projection Medial Rotation Patient Position: Part Position: Foot Leg and foot rotated Intermalleolar plane to IR Center to

Central Ray: to IR Midway Structures Shown:

Oblique Mortise Ankle Criteria for Evaluation The foot should be. The distal fibula should be demonstrated. Lateral mortise ( joint) should be joint should be open. Medial mortise. The lateral and medial malleoli should be demonstrated. The tibia should be very slightly superimposed.

Oblique Mortise ankle Error the leg is this causes the talofibular joint enough and the medial and lateral malleoli are not from the IR. Correction - Rotate the lower leg ( ) until the malleoli are from the IR.

Oblique Mortise ankle Error the foot is flexed this will cause the to be too close to the and will obscure the joint. Correction: the foot. Good image Calcaneus Fx. patient unable to dorsiflex foot

ANKLE AP Oblique (45º) Projection Medial Rotation Patient Position: Central Ray: to IR Midway Part Position: Foot Leg and foot rotated Center to (midway between )

Structures Shown:

Oblique 45 degree ankle Criteria for Evaluation The medial mortise should be, the lateral mortise is. The fibula should be demonstrated. The should be demonstrated distal to the lateral mortise and fibula. The should be slightly seen.

Oblique 45 degree ankle Error - rotation the fibula will be superimposed on the and the will be completely open. Good image Correction - foot and decrease rotation of leg to degrees

Oblique 45 degree ankle Error - rotation and foot is, the sinus tarsi is, and the fibula is superimosed on the. Correction: foot and rotation of leg to degrees Good image

Comparison AP 15-20 Mortise 45 Oblique

ANKLE Lateral (Mediolateral) Projection Patient Position: Part Position: Leg and foot in of ankle on IR foot to with leg Center to

Central Ray: to IR Alternate ( ) projection

Structures shown:

Lateral ankle Criteria for Evaluation The long axis of the foot is The talofibular joint The distal fibula is superimposed over the The domes of the talus The is seen

Lateral ankle Error; leg is rotated, the fibula is too far, the talus is. Correction rotate leg.

Trimalleolar Fracture includes:

STRESS METHODS Stress views demonstrate ruptures of ligament is seen as a Stress Inversion Shows ligament

Stress Eversion Shows ligament

Alternative Method AP Ankle & Lateral

Patient Position: LEG AP Projection Part Position: Leg in Foot is to º Femoral condyles to IR Central Ray: to IR of leg

Structures Shown:

Criteria for Evaluation: The long axis of the leg should be in alignment Ankle and knee joint Distal fibula superimposed over. Slight overlap of over tibia

Patient Position: LEG Lateral Projection Part Position: Turned Patella to IR Femoral condyles superimposed Knee flexed º

Central Ray: to IR of leg Note Cross-table lateral with horizontal beam is obtained if patient is unable to

Structures Shown: Criteria for Evaluation: The of the leg should be in alignment with the long axis of the IR. Ankle and knee joint Distal fibula lying over. Slight overlap

Lateral Leg error: Leg is ; head of fibula is from the tibia and the distal. Correction: roll patella to IR ( rotation of leg)

Lateral Leg error: Leg is ; head of fibula is and the distal fibula is. Correction: roll from the IR ( rotation of leg)

Situation: A radiograph of an AP ankle projection reveals that the lateral joint space is not open (lateral malleolus is partially superimposed by the talus). The superior and medial joint spaces are open. Is a repeat exposure necessary? Solution:

Situation: A radiograph of a AP mortise projection of the ankle reveals that the lateral malleolus is slightly superimposed over the talus and the lateral joint space is not open. Solution: Insufficient rotation of the foot and ankle was most likely the cause for this radiographic outcome.

Situation: A patient enters radiology with a possible ligament tear to the lateral aspect of the ankle. Initial ankle radiographs are negative for fracture or dislocation. Because the clinic is in a rural setting, the patient cannot have an MRI performed to evaluate the ligaments of the ankle. Solution: AP projections may provide an assessment of the soft tissue structures of the ankle.