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semilunar cartilages is another name for __? what is the purpose of these?
- menisci
- increase radius of curvature of tibial condyles, distribute weightbearing, decrease friction
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contours of 3 surfaces of menisci
- sup: concave w femoral condyles
- peripheral: adherent to capsule
- inf: almost plane, resing on edge of med and lat tibial condyles
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menisci are shock absorbers, taking how much force in ext and flex? if they were gone...?
- 50% in ext
- 85% in flex
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- w/o them - 2x force on femur, 6-7x force on tibia
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timing of appearance and vascularization for menisci
- appear as early as 8 weeks
- fully vascularized til 10 y/o, then the center 2/3rds become avascular
- supply to outer 1/3rd comes from capsule and synovium
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ant horns of menisci are attached to each other by the __ lig
transverse lig
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menisci attach around the periphery to the tibia by __ ligs
coronary/neiscobibial ligaments, composed of fibers from the anterior capsule
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menisci are attached to patella via __ lig
patellomeniscal/patellotibial ligaments - these are thickenings of the anterior capsule
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3 things that attach to the lateral meniscus that don't attach to the medial meniscus
- PCL
- popliteus muscle (via coronary lig and post. capsule)
- posterior meniscofemoral ligaments which attach to fem condyles
(and variable attachment to ACL)
connectionss are considered loose, tiving a fair amount of mobility on lateral tibial condyle
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3 things that attach to the medial meniscus but not lat meniscus
- MCL deep fibers
- semimembranosus through the capsule
- a few fibers from the ant horn of the ACL
these attachments are more firm and less moveable than those on the lat meniscus, therefor are torn more often
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shapes of the 2 menisci
- incomplete rings, crescehnt shaped, w ant and post horns
- lat: horns close together like a circle
- med: half moon
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going into flexion, which meniscus travels more?
dir of movement for flex/ext?
- lat recedes 2x as much as the med meniscus
- flex - they move post
- ext - they move ant
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motion of patella in flexion
moves inf 2x its length, followed by infrapatellar fat pad
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ratio of patella:lenght of patellar tendon
- 1:1 ideally, though longer for fems --> less stable
- smaller tendon--> patella goes inf
- longer--> sup
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articularis genu
- collectoin of small fibers from vastus intermedius
- moves suprapatellar bursa out of the way in ext
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4 types of patella displacements (must be 20% of the way to be a displacement)
- alta: superior
- baja: inferior
- squinting: medial
- bull frog eyes: lateral
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how patella is pulled during tibal rot
- ER - femur is medial to tib so pulls patella medially
- IR - the opposite
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transverse lig of the knee does what?
how is it attached to the patella?
- links the two ant horns of the menisci
- it's attached to the patella by strands of the infrapatella pad
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