In addition to quads & hamstrings, other knee muscles include sartorius, popliteus, gastrocs, and plantaris Knee rotation due to joint structure (vs. muscle function) aka screw home mechanism for stability in extension With slack ligaments, we have ~40˚ of rotation at 90˚ of knee flexion The knee is actually a double hinge with different shapes of fused lateral and medial condyles; this allows some rotation More flexion leads to more patella compression where the cartilage is the thickest Average Q-angle is ~15˚; beyond 20˚ is knock-kneed or genu valgus whereas less than 10˚is bow-legged or genu varum A shorter patellar tendon = baja while a longer one = alta Hamstrings are mostly strap/fusiform design, better for ROM & creates most force eccentrically (esp near end ROM) The articular cavity does not include the cruciate ligaments as the capsule folds around the intercondylar area Intercondylar eminence separates medial & lateral tibial plateau; gives rise to ACL & PCLs The patella encounters the condyles at 15-20˚ of flexion Medial femoral condyle twists inward toward lateral condyle in sagittal plane; both wider most distally In weight bearing (WB), femur rotates on tibia whereas in non- WB (NWB) tibia rotates on femur Compressive forces behind the patella increase by a factor of 0.5x body weight, 3.3x with stairs, & 7.6x with squats Menisci (shallow bowls of fibrocartilage) deepens tibial plateau with medial larger & oval shaped, while lateral smaller & rounder The patella, a sesamoid bone, slides against smooth space between condyles & provides an increased moment arm for the quads during knee extension Wedge-shaped menisci provide increased surface area and stability for the knee joint Medial femoral condyle is more curved & medial tibial condyle is more concave front to back The knee’s synovial membrane is the most extensive in the body with lots of bursae due to overlapping strap- like muscles The MCL resists valgus force while the LCL resists varus force The ACL resists anterior tibial glide while the PCL resists posterior tibial glide All knee ligaments are tightest in extension Quads are multipennate design, better for power, with the patella increasing peak torque @ ~60˚flexion Menisci are thinnest @ middle of joint and widest at outermost part In addition to quads & hamstrings, other knee muscles include sartorius, popliteus, gastrocs, and plantaris Knee rotation due to joint structure (vs. muscle function) aka screw home mechanism for stability in extension With slack ligaments, we have ~40˚ of rotation at 90˚ of knee flexion The knee is actually a double hinge with different shapes of fused lateral and medial condyles; this allows some rotation More flexion leads to more patella compression where the cartilage is the thickest Average Q-angle is ~15˚; beyond 20˚ is knock-kneed or genu valgus whereas less than 10˚is bow-legged or genu varum A shorter patellar tendon = baja while a longer one = alta Hamstrings are mostly strap/fusiform design, better for ROM & creates most force eccentrically (esp near end ROM) The articular cavity does not include the cruciate ligaments as the capsule folds around the intercondylar area Intercondylar eminence separates medial & lateral tibial plateau; gives rise to ACL & PCLs The patella encounters the condyles at 15-20˚ of flexion Medial femoral condyle twists inward toward lateral condyle in sagittal plane; both wider most distally In weight bearing (WB), femur rotates on tibia whereas in non- WB (NWB) tibia rotates on femur Compressive forces behind the patella increase by a factor of 0.5x body weight, 3.3x with stairs, & 7.6x with squats Menisci (shallow bowls of fibrocartilage) deepens tibial plateau with medial larger & oval shaped, while lateral smaller & rounder The patella, a sesamoid bone, slides against smooth space between condyles & provides an increased moment arm for the quads during knee extension Wedge-shaped menisci provide increased surface area and stability for the knee joint Medial femoral condyle is more curved & medial tibial condyle is more concave front to back The knee’s synovial membrane is the most extensive in the body with lots of bursae due to overlapping strap- like muscles The MCL resists valgus force while the LCL resists varus force The ACL resists anterior tibial glide while the PCL resists posterior tibial glide All knee ligaments are tightest in extension Quads are multipennate design, better for power, with the patella increasing peak torque @ ~60˚flexion Menisci are thinnest @ middle of joint and widest at outermost part
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In addition to quads & hamstrings, other knee muscles include sartorius, popliteus, gastrocs, and plantaris
Knee rotation due to joint structure (vs. muscle function) aka screw home mechanism for stability in extension
With slack ligaments, we have ~40˚ of rotation at 90˚ of knee flexion
The knee is actually a double hinge with different shapes of fused lateral and medial condyles; this allows some rotation
More flexion leads to more patella compression where the cartilage is the thickest
Average Q-angle is ~15˚; beyond 20˚ is knock-kneed or genu valgus whereas less than 10˚is bow-legged or genu varum
A shorter patellar tendon = baja while a longer one = alta
Hamstrings are mostly strap/fusiform design, better for ROM & creates most force eccentrically (esp near end ROM)
The articular cavity does not include the cruciate ligaments as the capsule folds around the intercondylar area
Intercondylar eminence separates medial & lateral tibial plateau; gives rise to ACL & PCLs
The patella encounters the condyles at 15-20˚ of flexion
Medial femoral condyle twists inward toward lateral condyle in sagittal plane; both wider most distally
In weight bearing (WB), femur rotates on tibia whereas in non-WB (NWB) tibia rotates on femur
Compressive forces behind the patella increase by a factor of 0.5x body weight, 3.3x with stairs, & 7.6x with squats
Menisci (shallow bowls of fibrocartilage) deepens tibial plateau with medial larger & oval shaped, while lateral smaller & rounder
The patella, a sesamoid bone, slides against smooth space between condyles & provides an increased moment arm for the quads during knee extension
Wedge-shaped menisci provide increased surface area and stability for the knee joint
Medial femoral condyle is more curved & medial tibial condyle is more concave front to back
The knee’s synovial membrane is the most extensive in the body with lots of bursae due to overlapping strap-like muscles
The MCL resists valgus force while the LCL resists varus force
The ACL resists anterior tibial glide while the PCL resists posterior tibial glide
All knee ligaments are tightest in extension
Quads are multipennate design, better for power, with the patella increasing peak torque @ ~60˚flexion
Menisci are thinnest @ middle of joint and widest at outermost part
