Ch.6 - Lower leg, Knee, Patella, Femur

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Cards (57)

  • The femur is the longest and strongest bone in the body
  • The patella is .5" above the knee joint
  • The patellar surface is aka the trochlear groove or intercondylar sulcus
  • The patellar surface is the triangular depression at the distal portion of the anterior femur.
  • Femur Angles:
    • Neck to shaft: 125 degrees
    • Longitudinal: 10 (5 - 15) degrees
    • Anterior: 15 - 20 degrees
  • The femur's medial condyle extends lower than the lateral condyle ( this is why we angle 5-7 degrees on lateral knees)
  • The posterior view of the distal femur shows its both condyles and the intercondylar fossa between them.
  • The medial condyle has an adductor tubercle on its posterolateral surface; this is how we can differentiate it from the lateral condyle
  • The patella has a base (superior border), apex (inferior surface), posterior surface (smooth) and an anterior surface (rough)
  • The patella only articulates with the femur, hence the patellofemoral joint
  • The knee joint is dependent on the PCL and ACL (ligaments) for stability
  • The knee is a synovial joint enclosed in an articular capsule/bursa
  • All lower limb joints except for the distal tibiofibular joint are synovial, diarthrodial (freely movable) joints
  • The distal tibiofibular joint is a fibrous amphiarthrodial (slightly movable) joint
  • The SID for an AP Lower Leg is 40" but you may increase it to 44-48
  • AP Knee Angulations:
    • <19 cm: 3-5 degrees caudad
    • 19-24 cm: No angle, perpendicular
    • >24 cm: 3-5 degrees cephalad
  • AP Lower Leg:
    • SID: 40" or 44-48"
    • 14x17 diagonally
    • 1-2" of both joints included
  • AP Knee:
    • 40" SID
    • CR at .5" distal to apex of patella
    • Angle 3-5 degrees based on body habitus
    • Rotate leg 3-5 degrees internally
  • Oblique knees don't require an angle
  • A knee internal oblique opens up the tibiofibular joint while the external closes it
  • Lateral Knee:
    • CR angled 5-7 degrees cephalad
    • CR 1" distal to medial epicondyle
    • Flex knee 20-30 degrees
  • Lateral Knee Angles:
    • Short with wide pelvis: 7-10 degrees
    • Average: 5-7 degrees
    • Tall with narrow pelvis: 5 degrees
  • AP Weight Bearing Knees are done to demonstrate the femorotibial joint spaces for possible cartilage degeneration or arthritis
  • PA Axial Weight Bearing Knees (Rosenberg Method):
    • Knees flexed 45 degrees
    • CR 10 degrees caudad
    • Knee joint spaces and intercondylar fossa shown
  • Intercondylar Fossa Views:
    • Camp-Coventry Method
    • Beclere Method
    • Homblad Method
  • Camp Coventry Method:
    • PT prone with lower leg flexed 40-50 degrees
    • CR perpendicular to lower leg
    • CR at popliteal line
  • Beclere Method:
    • PT supine with knee flexed 40-45 degrees
    • CR perpendicular to lower leg
    • CR 1" distal to apex of patella
  • You should rotate the knee internally 3-5 degrees for a true PA Patella
  • Medio Lateral Patella:
    • Flex knee 5-10 degrees
    • CR perpendicular to mid-femoropatellar joint
  • Tangential Patella Views:
    • Settegast Method
    • Inferiosuperior Projection
    • Hughston Method
  • Settegast Method:
    • PT may be prone or seated
    • 90 degree knee flexion
    • CR 15-20 degrees up to patellofemoral joint
  • Inferosuperior Projection:
    • 40-45 flexion of knee
    • CR inferosuperiorly at 10-15 degrees from lower leg
  • Hughston Method:
    • PT prone
    • Knee flexed 40 degrees
    • CR 15-20 degrees to lower leg at mid femopatellar joint
  • Distal AP Femur:
    • Rotate leg 5 degrees internally
    • Bottom of IR 2" below knee joint
  • AP Proximal Femur:
    • Rotate leg 15-20 degrees internally (femoral neck in profile)
    • Top of IR at ASIS level
  • Lateral DIstal Femur:
    • Flex knee 45 degrees
    • Bottom of IR 2" below knee joint
  • Lateral Proximal Femur:
    • True lateral
    • Top IR at ASIS
  • kVp Ranges:
    • TibFib: 70 +-5
    • Knee/Patella: 75 +- 5
    • Distal Femur: 75 +- 5
    • Proximal Femur: 80 +- 5