Standard Knee Series AP Knee Lateral Knee Tunnel Knee

AP Knee pt is positioned with 15 o of internal rotation of the foot femorotibial joint spaces should measure between mm

Lateral Knee approximately degrees of flexion of the knee

Blumensaat’s line Dense white line representing the surface of the intercondylar notch that is tangential to the x-ray beam.

Ludloff’s Patch distal femoral epiphysi sA lucency in the distal femoral epiphysi s best seen around the age of 16 years

3 year male The ossification center for the patella is first apparent. years of agenormal patellar ossification does not begin until years of age

The patellar ossification center is more prominent, and a normal pronounced indentation is evident at the anterior portion of the tibia at the eventual site of the tibial tubercle. 5 year male

Patellar Position Patella AltaPatella Alta - patellar ligament greater than 20% longer than the patella Patella BajaPatella Baja - patella positioned too low the greatest length of the patella and the length of the patellar tendon (ligament) should be equal (20% variation is acceptable)

Tunnel Knee approximately 45 o of knee flexion and a 45 o caudad tube tilt

Accessory Projections

Tangential Patella aka Sunrise Patellaaka Sunrise Patella lateral vs medial patellofemoral joint space Lateral Medial

Bilateral AP Weightbearing Knees

Oblique Knee

Normal Variants of the Knee

Patella agenesis Rare. Usually associated with hereditary osteo- onychodysostosis.

Nail Patella Syndrome AKA Fong’s Syndrome, HOOD syndrome hypoplastic or absent patella nail abnormalities may see kidney dysfunction and webbing of the elbow iliac hornsiliac horns elbow abnormalitieselbow abnormalities

Harris Lines Growth Arrest Linesaka Growth Arrest Lines represents areas of growth arrest resolution

Bipartite Patella bilateral 80% of the time

Tripartite Patella

Os Cyamella popliteus tendonaccessory ossicle in the popliteus tendon

Os Fabella lateral head of the gastrocnemiu s musclesesamoid bone located within the tendon of the lateral head of the gastrocnemiu s muscle bilateral in 2/3 to 3/4 of individuals

Dorsal defect of the patella Variant in ossification. Circular radiolucent defect in superolateral pole of patella. May simulate neoplasm. May be related to bipartite patella.

Self limiting. Incidental finding in children.

Osgood- Schlatter’s Disease m/c in males years of age fragmentation of the tibial tuberosity

Sinding-Larsen- Johannsen Syndrome inferior pole of the patella

Pellegrini- Steida medial collateral ligamentcalcification of the medial collateral ligament usually follows previous trauma

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