Anatomy (PT) KNEE
oblique popliteal ligament
- expansion of semimembranosus tendon - reinforces posterior knee especially in area of intertrochanteric
facet
part of a bone that articulates with another bone
bakers cyst
popliteal bursa can get a buildup of synovial fluid
MCL
primarily resists VALGUS stress -taut in full extension -also resists lateral tibial rotation and medial femoral rotation
LCL
primarily resists VARUS stress -also taut in full extension -also resists lateral tibial rotation and medial femoral rotation
patellar ligament
strong fibrous band -maintains alignments of patella -receives medial and lateral retinacula (therefore it also plays a role in keeping patella in correct alignment during motion)
Q-angle
the valgus angulation between the pull direction of the quadriceps m and patella tendon
based
top of patella (wider portion)
deep (has fibers that blend with medial meniscus) superficial (more vascularized and first to be injured)
what are layers of the MCL
rectus femoris, hamstrings -hip position may affect force output of these muscles across the knee -hip position may affect ROM measurements across the knee
what are some considerations for two joint muscles regarding the knee and hip
tibiofemoral patellofemoral proximal tibiofibular
what are the 3 joints of the knee complex
inferior aspect of patella to tibial tuberosity
what are the attachments of the patellar ligament
superolateral: biceps femoris superomedial: semiten/semimem inferolateral: lateral head of gastroc inferomedial: medial head of gastroc
what are the boundaries of the popliteal fossa
termination of small (lesser) saphenous v. -popliteal artery and vein -tibial nerve -common peroneal nerve -posterior cutaneous nerve (of thigh) -popliteal lymph nodes and vessels
what are the contents of the popliteal fossa
anterior-medial bundle (most taut in flexion) posterior-lateral bundle (most taut in extension)
what are the functional bundles of the ACL
deepen joint surface and increase congruency/contact area -absorb shock -distribute weight-bearing/load transmission -provide stability -aid in lubrication of joint
what are the functions of the menisci
Ligament of Humphrey ligament of wrisberg (most people have one or the other)
what are the menisocofemoral ligaments called
tibial nerve: posterior compartment, mostly innervates nerve that plantar-flex ankle deep peroneal nerve: goes into anterior compartment (dorsiflexors) superficial peroneal nerve: goes into lateral compartment (evertors)
what are the nerves of the compartments of the lower leg
arcuate popliteal ligament popliteus muscle oblique popliteal ligament
what are the posterolateral corner stabilizers
roof: skin and fascia floor: femur, knee joint capsule, popliteal fascia
what are the roof and floor of the popliteal fossa
medial: MPFL, some fibers of vastus medialis lateral: vastus lateralis, blends with retinaculum and blends a little with IT band
what are the structures that cause medial and lateral patellofemoral tracking
sartorius, gracilis, semitendinosus
what are the tendons of the pes anserine in the CORRECT order
if someone hits your lower leg forward or your upper leg backwards
what are two ways that your ACL could be torn
the MCL is injured more frequently because its attached to MCL and there is less ability to slide out of the way
what collateral ligament is injured more frequently
MCL, therefore is injured more
what collateral ligament is weaker, MCL or LCL
they both secondarily help limit internal rotation of tibia (AKA external rotation of femur)
what do the ACL and PCL do in regards to hip rotation
the two bundles wind around each other to become tighter
what do the bundles of the ACL do when the knee is in motion
anterior: ankle eversion posterior: ankle inversion
what does posterior glide and anterior glide of the tibiofibular joint accompany
medial facet is larger than the lateral facet (50% larger)
what facet of the knee is larger
infra-patellar fat pad
what fat pad of the knee is often most problematic
superficial, but has a better vascular supply so is more likely to heal on its own
what fibers of the MCL are injured more frequently
lateral patellar tracking is more common.
what happens more often lateral or medial patellar tracking?
the part of the patella that is touching the femur changes
what happens to the contact area of the femur and patella as the knee moves between flexion/extension
open packed -minimizes influence of bony architecture, menisci, and hamstrings in providing additional stability
what is better when testing ligaments, the open or closed pack position?
full extension
what is considered the most stable position of the knee
ACL is weaker, poor blood supply and will likely not heal on own
what is structurally weaker between the cruciate ligaments
it depends on the position the knee is in. -when the knee is flexed slightly IT band acts as a secondary knee extensor -once your knee is flexed past 30 degrees the IT band acts as a secondary knee flexor
what is the action of the IT band
open packed: 30 degree flexion closed packed: full extension
what is the closed and open packed position of the tibiofemoral joint
protects the anterior knee -increase the mechanical advantage of the quadriceps muscle
what is the function of the patellofemoral joint
stabilize posterolateral corner. if these are injured, you get a " "rotary instability' (tibia is rotating too much unde femur)
what is the main function of the arcuate popliteal ligament
anterior transverse meniscomeniscal
what is the most common
menisci glide anteriorly with extension; posteriorly with flexion
what is the motion of menisci during extension and flexion
popliteus. contracts the unscrew the knee (ruled more important in weight bearing)
what is the muscle responsible for "unlocking" the knee
men: 14 degrees women: 17 degrees (women are higher because wider pelvis for childbirth)
what is the normal Q angle range
Intracapsular but extrasynovial (inside joint capsule but not inside synovial membrane. therefore do not get nutrition from synovial membrane)
what is the nutrition of the cruciate ligaments
open packed: full extension closed packed: full flexion
what is the open/closed packed position of the patellofemoral joint
epicondyles are on top condyles are below
what is the positioning of the epicondyles and condyles
limit anterior translation of tibia from under the femur (aka posterior translation of femur on tibia)
what is the primary function of the ACL
limit posterior translation of the tibia on the femur (aka anterior translation of femur on tibia)
what is the primary purpose of the PCL
both menisci have coronary ligaments, they attach meniscus on tibia (holds down onto tibia)
what is the purpose of the coronary ligaments
serve as secondary restraint to posterior tibial translation
what is the purpose of the meniscofemoral ligaments
improve line of pull of the quadriceps muscle and give it more mehcnaical advantage -can create more movement with less force -makes lever longer
what is the purpose of the patella
innervated with mechanoreceptors -tell brain when ligament is taut and in dangerous position for injury. -position and/or veloicty info during movement
what is the sensory role of capsule and ligaments
modified plane joint (functions mostly like a regular plane joint. gliding and sliding)
what kind of joint is the patellofemoral joint
bicondylar synovial joint (allows flex/ex, ER/IR)
what kind of joint is the tibiofemoral joint
plane synovial joint (can bear 1/6 weight)
what kind of joint is the tibiofibular joint
medial meniscus attaches to MCL lateral meniscus does NOT attach to LCL
what meniscus attaches to what collateral ligament?
biceps femoris IT band
what muscles are responsible for lateral tibial rotation
pes ans med ham popliteus
what muscles are responsible for the medial tibial rotation in NWB
inner 1/3 doesnt have blood supply outer 1/3 has blood supply (middle can be hit or miss)
what part of the menisci has blood supply
frontal plane movement (valgus and varus)
what plane of movement do the collateral ligaments prevent?
bicondylar "modified hinge joint"
what type of joint is the knee joint
during 20, 45 and 90 degrees of flexion
when are lateral and medial facets of the patella touching the femur?
when you are in flexion, the patella is nestled into trochlear groove on femur. when you are in extension, patella is not in groove and is just resting on top. also ligaments that help hold patella in place are tighter in flexion and don't allow much movement
when is it easier to move the patella? why?
OKC: greater from 0-45 degrees CKC: from 45-90 degrees
when is the PFJR and contact stress greater in OKC and CKC exercises
when the knee is extended
when is the bony congruity the best at the knee
at end range flexion, patella will tilt toward the medial side and this is when odd facet is touching.
when is the odd facet of the patella the ONLY facet touching the femur
the external margins
where does the mensici have thicker margins
because of the poor bony congruency
why are ligaments so important in the knee
important in the knee since the bone congruity is so poor
why are the menisci so important
yes they have a great blood supply, can head and can hurt if injured
are fat pads vascularized?
fibrous capsule (of joint capsule)
arises above the femoral condyles and blends with ligaments and musculature
meniscomenical ligaments (4 types)
attach meniscus to each other how many types of these?
synovial capsule (of joint capsule)
attaches to the edges of articular cartilage and below the menisci
apex
bottom of patella (narrower portion)
genu varus
bow legged
yes. they are both taut in extension, therefore a hyperextension force could result in injury to both
could the MCl or LCL be injured in a hyperextension MOI?
femur moving on tibia convex on convace --> roll and glide in OPPOSITE direction extension: anterior roll/post. glide flexion: posterior roll/ant. glide
describe the arthrokinematics of the tibifemoral joint for CKC
tibia moving on femur concave on covex --> roll and glide in SAME direction extension: anterior roll AND glide flexion: posterior roll and posterior glide
describe the arthrokinematics of the tibiofemoral joint for OKC
epicondyles do not fit well into condyles (poor bony congruity) stability comes from ligaments and muscle strength, due to poor bone congruity
describe the bony congruency of the knee joint
contact area goes from distal to proximal on surface of patella as the knee is flexed -contact area becomes larger as knee is flexed
describe the contact areas of the patella
full extension: no contact between patella and femur -as you begin to flex, the most inferior portion (apex) of patella will start contacting femur. -as you continue flexing, will move superiorly on patella
describe the contact of the patella and femur during flexion and extension
most motion occurs in flexion/extension -little rotation is available
describe the motion in the knee joint
-increased flexion moment arm of gravity or external resistance -quads have to create more force to do exercise -PFJR force peaks at 35 (most compressive) -decreased contact area results in increasing contact stress from 90 to 20 degree of flexion
describe the patellofemoral biomechanics during open chain leg extension, free weight
10-15 degrees of lateral tibial rotation at end range extension
describe the screw home mechanism for non weight bearing
10-15 degrees of femoral medial rotation at end range extension
describe the screw home mechanism for weight bearing
popliteal fossa
diamond shaped depression of the posterior aspect of the knee
no, popliteus is in the way
does the LCL attach to the lateral meniscus or capsule
extension: patella glides superiorly flexion: patella glides inferiorly
during extension and flexion of the knee what way does the patella glide?
plica
extra bits of synovial tissue, where synovial membrane folds over on itself
menisci
fibrocartilaginous structures -made up primarily of type 1 collagen -collagen bundles arranged outside to inside -radial fibers woven in between
arcuate popliteal ligament
head of fibula, splits in tow. one goes to femoral condyle/ epicondyle, other goes into blend with oblique popliteal
VMO (Vastus Medialis Oblique)
helps stabilize patella on medial side. -you CANT't isolate this
named for how they attach on the TIBIA
how are they cruciate ligaments named?
they are somewhat enclosed by fibrous capsule, NOT inside synovial joint (cant get nutrition from synovial knee joint, means capacity for healing is relatively poor)
how do the ACL and PCL fit within joint capsule
anterior intercondylar region of tibia, travels superiorly and laterally to attach to lateral condyle of femur
how does the ACL travel and attach on the tibia and femur
posterior intercondylar area of tibia, travels superiorly and anteriorly and attaches to medial condyle of femur
how does the PCL travel between the tibia and femur
angle from ASIS to center of patella to tibial tuberosity
how is Q angle measured
genu valgus
knock knees (relative to hips) knee are in and feet are out
flexion > extension restrictions
A person with a capsular pattern at the tibiofemoral joint will lose more flexion or extension?
Menisofemoral ligaments
ligaments that attach lateral meniscus to femur
