The knee Flashcards
the knee joint is made up of how many:
- Bones
- Articulating surfaces
- Compartments
- Mensici
- Joint capsules
- 3 bones
- 3 articulating surfaces
- 2 menisci
- 1 joint capsule
the knee joint can withstand forces how many times your body weight
4-6 x body weight
why is the knee joint ones of the most commonly injured joints?
becuase it is positioned between 2 long bony levers
what condyle is larger on the femur
the medial condyle
the intercondylar groove of the femur has a larger _____ projection on the lateral condyle, this is to prevent?
- anterior
- prevent patellar dislocation
if the ______ projection of the intercondylar groove is inadequate it can cause patellar instability
anterolateral
the cruciate ligaments lie in what part of the femur?
intercondylar fossa
what condyle is larger on the tibia
the medial
where does the patellar tendon insert
on the tibial tuberosity
what part of the fibula is in the knee joint
head of the fibula
the patella is the largest _____ bone in the body
sesamoid
the patella has the thickest ?
articular cartilage
the base of the patella is where? and the apex?
base= superior apex= inferior
how many degrees of freedom does the knee joint have
2 DOF
what are the movements of the knee joint
flexion, extension, and a little axial rotation
what are the osteokinamatic movements of the knee joint
swing
spin
what is the largest joint in the body
knee
how many degrees does the knee flex? and extend?
- 130-150 flexion
- 0-15 hyperextension
what is the end feel of knee flexion and extension
soft
firm
the degrees someone can flex will varying depending on?
size of muscle mass
the axis of motion of the knee is located a few cm _____ the joint line, passing horizontally through the _____
above,
femoral condyles
the condylar surface of the femur is much bigger than that of the tibia, what does this mean in regard to arthrokinametics?
- Must roll and glide
- the conter of motion CHANGES as the knee flexes and extends
- –> axis moves about 2cm translation (tibia moves)
with the axis of the knee moving with flexion and extension, what is made hard?
it is hard to create mechanical hinge joint devices such as goniometer, isokinetic dynamometer, knee-ankle-foot orthosis, or below knee prosthesis
the arms of the mechanical devices for the knee cannot remain parallel to the thigh and leg, what does this result in?
- motion or pressure between the mechanical and anatomical parts
what plane and axis does rotation of the tibia and fibula occur in
- transverse plane around the vertical axis that is just medial to the tibial intercondylar ridge
the tibia and fibular rotate ____ to each other
relative (could also be said that the lateral condyle rotates around the medial condyle)
with the knee flexed to 90 degrees, the ligaments are ____ allowing for ____
slackened, allowing for transverse rotation
with the knee fully extended, the collateral and cruciate ligaments are ___ and contribute to _____
tense, joint stability
total range of transverse rotation of the tibia is how many degrees?
- external rot?
- internal rot?
- 40 degrees
- 25
- 15
what is the end feel of rotation in the knee
firm
rotation motion of the knee is limited by ?
capsular and ligamentous structures
- collateral, cruciate, anterior lateral, oblique popliteal ligaments, coronary ligaments, retinacula and IT band
during the last 20 degrees of knee extension what happens? how does this change if the fix the tibia)
the tibia externally rotates about 20 degrees on the femur (tibia= lateral)
- femur rotates medially on the tibia
the 20 degrees of rotation in the last 20 degrees of extension allows for?
- permits humans to stand erect without quadriceps muscle contraction and withstand anterior -posterior forces on the extended knee
what structures of the knee are female and male
- this means?
- tibia surfaces are female and femoral condyles are male (in both directions)
- -> the tibia moves in the SAME direction as the osteokinamatic motion (roll and glide in the same direction)
the tibia articular surfaces are divided by ?
the intercondylar eminance
what does the bigger medial condyle result in ?
lateral rotation with extension
cruciate ligaments are INSIDE the _______ but OUTSIDE the _______
- capsule
- synovial lining
the joint capsule forms a sleeve around the joints, above the ____ condyles and below the _____ condyles
above, below
the capsule is reinforced by ?
retinaculum and ligaments
there is a cut out for what in the capsule?
the patella, anteriorly and central fold posteriorly (caved in)
the tibiofemoral capsule is made up of a inner ? and outer?
- inner synovial lining
- outer fibrous layer
the synovial lining goes on the ____ of the cruciate ligaments
outside
do the layers of the tibiofemoral joint adhere throughout capsule
no
2 characteristics of the tibiofemoral capsule
- suprapatellar pouch
- multiple bursa and fat pad to assist with reducing friction about the knee
what bursa communicates with the knee joint
suprapatellar bursa
the patellofemoral joint is the articulating surface between the ?
posterior surface of the patella and intercondylar surface of the femur (1 of 3 joint compartments)
the tibiofemoral joint makes up ? of 3 joint compartments of the knee
2
what are the functions of the patella?
- increase leverage or torque of the quadriceps muscles by increasing its distance from the axis of motion
- prevent damaging frictional or compression forces on the quadriceps tendon with full range resisted knee flexion / extension activities
by what percent does the patella increase the effectiveness of the quads
30-50%, (13% at 90-120 and 31% at 0-5) , but with considerable retropatellar compression force
where is the thickest hyaline cartilage we have in our bodies?
-back of the patella (need it because it gets pulled into the femur)
what can be a major issue if you dont have a patella
- all your quads insert on the tibial tuberosity, without the patella the quadriceps tendon will rub over bone and get worn out
Quadriceps mechanisms stabilizes the patella and guides its motion via?
lateral and medial retinaculum
what anchors the patella to the tibial tuberosity
the strong patellar tendon
how much should the patella move in full extension
half its width (with joint play)
at what facet is the patella in contact with at 0-10 degrees
no contact
at what facet is the patella in contact with at 10-20 degrees
inferior facet
at what facet is the patella in contact with at 45 degrees
middel facet
at what facet is the patella in contact with at 90 degrees
superior facet
at what facet is the patella in contact with at 120 degrees
ODD facet - medial
with the knee fully extended, what is the patellar apex in line with?
the tibiofemoral joint margins
patella baja
inferiorly placed patella
patella alta
superior placed patella
what way does the patella move with flexion and what way with extension?
- flexion = inferolaterally
- extension= supermedially
what does poor tracking of the patella cause?
wears out the back of patella and causes pain
what forms the Q angle? and what is it in women and men?
- formed between the longitudinal axis of the femur and the patellar tendon
- 15 degrees in women
- 10 degrees in men
a Q angle greater than ___ degrees result in higher incidents of patellofemoral joint abnormalities. What are 2 ?
- 20 degrees
- patellofemoral tracking problems
- chondromalacia patella (sad cartilage of patella)
what are patellofemoral joint abnormalities common?
in young females going through puberty (widening pelvis)
Menisci are semiulnar wedge shaped, made of ______, and thickest where?
- fibrocartilage
- outer rim
6 functions of menisci
- deepen socket and improve congruency
- distribute pressure more evenly and increasing weight bearing surface
- shock absorption
- promote lubrication of joint (synovial fluid flows where there is pressure)
- prevent joint capsule from intruding into joint space
- partially protect against excessive motion
where do mensici have blood supply to, what does this mean when getting a radial tear vs a bucket handle tear
the outer edge
- radial tear heals better because it gets a blood supply,
- a bucket handle tear is usually cut of
the menisci moves with ?
flexion and extension
the medial menisci is C shaped and attaches to what?
the medial collateral ligament and capsule
what menisci is more commonly injured and moves less?
medial (it is tethered to the medial collateral ligament)
how much does the lateral menisci move? what can happen if it fails to move?
12 mm
- it can be ripped or crushed
how do you test the medial collateral ligament?
- apply a valgus stress to the tibia while holding the femur
how do you test the lateral collateral ligament?
- apply a varus stress to the tibia and push the femur out
how do you tell if a collateral is strained?
if it gives in both direction when you test, and you can diagnose based on the pain scale
what prevent medial lateral movement of the knee
- medial collateral (tibial collateral)
- lateral collateral (fibular collateral
what prevents abduction of the tibia on the femur
MCL
what prevents adduction of the tibia on the femur
LCL
when do the collateral ligaments become slack?
what do you do in this position?
at 20 degrees flexion
- test for collateral ligament strain in this position
why is the medial collateral ligament more commonly injured
mechanism of injury
what provide control and stability throughout flexion
ACL and PCL
where do the ACL and PCL lie?
within the femoral intercondylar fossa
where does the ACL run from? (origin and insertion)
from the anterior tibial intercondylar eminence to the posteromedial corner of the lateral femoral condyle in the intercondylar notch
(medial side of the lateral condyle)
where does the PCL run from (origin and insertion)
from the posterior tibial intercondylar eminence to the anterolateral aspect of the medial femoral condyle in the intercondylar notch (medial side of the medial condyle)
Curiate ligaments are ____capsular and _____synovial
intra, extra
the cruciate ligaments maintain constant length throughout ______ and ________
flexion and extension (not all parts of each ligament are taut simultaneously
the ACL helps prevent _______ displacement of the tibia on the femur,
the PCL helps prevent _____ displacement of the tibia on the femur
anterior, posterior
Arcuate ligament, popliteal fibular and oblique popliteal ligament are important for ________ stability
posterior
Popliteal fibular ligament is important for ______ stability and ________ stability of the knee, it is attached to what?
posterior, locking
- attached to the popliteus which is the muscle for unlocking the knee
where does the arcuate popliteal ligament run from ?
Y shaped head of the fibula to posterior tibial intercondylar area (joins oblique pop lig) and lateral epicondyle (joins gastrocs)
oblique popliteal ligament runs from?
semimembranous tendon to the posterior lateral epicondyle
where does the popliteal fibular ligament run from ?
popliteal tendon to fibular head
what 4 ligaments provide meniscal stability
- posterior meniscofemoral
- anterior meniscofemoral
- coronary
- transverse genual
where does the posterior meniscofemoral ligament run from?
POSTERIOR horn of the lateral meniscus to post MEDIAL femoral condyle (posterior to PCL)
where does the anterior meniscofemoral ligament run from?
POSTERIOR to horn of lateral meniscus to post MEDIAL femoral condyle (anterior to PCL)
where does the coronary ligament run from?
menisci to the tibial plateau
where does the transverse genual ligament run from?
connects anterior margins of menisci
what nerve innervates the rectus femoris
femoral nerve
what nerve innervates the vastus lateralis, medialis and intermedius
femoral nerve
what is the only quadricep muscle that could not extend the leg at the knee by itself
vastus medialis
the vastus medialis longus , superior longitudinal fibers are directed ____ - ___ degrees _____
15-18 degrees medially
in the vastus medialis the top fibers are more ______ and the lower fibers (by the knee) are more _____, so researchers broke it into?
- vertical, horizontal
- the vastus medialis longus and vastus medialis oblique
the vastus medialis oblique, fibers run for from an angle of ____ to _____ degrees
50-55 degrees
what are 2 functions of the vastus medialis oblique
- plays important role in keeping the patella on track in gliding on the femoral condyles (pulls it medially when you contract)
- counteracts the laterally directed forces of the vastus lateralis
what does the articularis genus do?
tenses the knee joint capsule proximally with knee extension
- -> pulls the suprpatellar birsa superiorly
- -> prevents impingement of synovial membrane between petalla and femur
what nerve innervates the sartorius
femoral nerve
what nerve innervates the biceps femoris
sciatic nerve (tibial and common peroneal nerve)
what nerve innervates the semimembranosus and semitendinosus
sciatic (tibial n)
what nerve innervates the gracilis
obturator n
what nerve innervates the popliteus
tibial nerve
what nerve innervates the gastrocnemius
tibial nerve
what nerve innervates the plantaris
tibial n (b/c posterior)
pes anserine bursitis is the conjoined tendons of 3 lower extremity muscles:
- sartorius
- gracilis
- semitendinosus
the tendons of the muscles involved in pes anserine insert on the anteromedial proximal tibia, lying superficial to the _________, whose purpose is to ?
- pes anserine bursa
- reduce friction between the tendons and the tibia
risk factors of pes anserine? (6)
- right hamstrings or other involved muscles (say grace before tea muscles)
- pes planus (overpronation of foot)
- overpronation during running (knock knees)
- obesity
- genu valgum
- weak lateral rotators of the hip
- -> all these things puts strain on the pes anserine
mechanoreceptors for sensory innervation and reflexes are embedded in
- ligaments (cruciate; collateral)
- capsule and synovial lining
- menisci (peripheral edges)
reflexes of the ACL are inhibited with 60ml of swelling, this is called
knee effusion
______ and _______ can limit some joint movements mostly at end range, but ______ are necessary to produce to forces required to stabilize the knee during movement (ie, climbing stairs)
ligaments, capsule, muscles
the ligaments and capsule in the knee provide important _________ information to allow the muscles of the knee to appropriately stabilize the joint while under load .
- –> this information is important to?
- -> this is especially evident with ?
proprioceptive
- reduce the load on some ligaments
- ligament ruptures
(eg, complete rupture of ACL increased EMG of medial head of gastroc)
what are the 5 muscles acting on the knee that are ONE joint muscles
- 2.3. three vastus
- popliteus
- short head of the biceps femoris
what are the 9 muscles that act on both the hip and the knee
- rectus femoris
- sartorius
- gracilis
- semitendinosus
- semimembranosus
- long head of the biceps femoris
- TFL (via IT band)
what are the 2 muscles that cross both the knee and the ankle
the gastroc and the plantaris
in natural motions, the 2 joints usually move in directions such that the muscle is relatively _______ over one joint while producing movement and ______ at the other joint
–> these results in
elongated, shortened
- favourable length -tension relationship and efficient energy output of the muscles
squatting motions include:
- squatting itself
- rising from a sitting position
- climbing stairs
during squatting actions the hamstrings act as ____ extensors while the quadriceps at as ____ extensors
—> _____ actions of both muscles groups control the rate
- hip
- knee
- eccentric
explain what happens as a person lowers into a squat
* check this is right
- at the ankle the gastroc and soleus eccentrically allow the ankle to dorsiflex
- at the knee, the quads work eccentrically (lengthening over the knee)
explain what happens as a person rises in a squat
* check this is right
- the quads work concentrically extending the knee
- gastrocs and soleus plantar flex ankle
- gastrocs plantar flex working concentrically as it lengthens over the knee and shortens at the ankle (optimal contractile conditions for plantar flexion)
when we are down in a squat and rise onto our toes why is it harder than rising on our toes when standing
the gastroc is shortening over both joints becuase the knees are flexed = less power
tibiofemoral forces during walking have been calculated to be up to ___ x body weight at the beginning of the single -leg stance phase
6
during the middle stance phase , tibiofemoral forces are ___x the body weight and at the end of the stance phase, forces ride again to ___x the body weight
1, 4
in the swing phase, tibiofemoral forces are ___ than body weight
less
when running, tibiofemoral forces are __ - ___ x body weight
10-12
tibiofemoral forces are implications for?
weight gain and OA
what happens often with a knee injury
there is altered biomechanics leading to extensive wear and tear that results in repeated microtrauma and its subsequent degenerative results
conditions that alter the normal torque and knee biomechanics may include (8)
- meniscal tears
- ligamentous instability
- IT band tightness
- obesity
- genu varus or valgus
- traumatic or surgical shortening of the neck of the femur
- excessive eversion/pronation of the foot
- changes in alignment of the femur, tibia or foot from fractures
genu varus = more pressure on the ?
genu valgus = more pressure on the?
- medial side
- lateral side
areas receiving excessive physiological pressure over years may develop ? ( 3)
- pain
- destruction of the cartilage
- osteoarthritis
normally when the ACL is torn, it common to have the common triad torn. the common triad consists of?
- meniscal tear
- ACL tear
- MCL tear
what are the treatments for terrible triad injury
- long term risk for?
partial menisectomy and ACL reconstruction. MCL repair.
- OA
retropatellar pain is known as ? or ? or ?
- chondromalacia patellae
- runners knee
- patellofemoral pain syndrome
what is the etiology of chondromalacia patellae
–> there is pain with ?
a soreness and aching around the or deep to the patella due to mistracking of the patella, articular surface related, kinetic chain
- pain with deep squats 8x BW acting on patella
what are potential causes of chondromalacia patellae (4)
- tightness, imbalance or weakness of the thigh muscles
- tightness of the lateral retinaculum
- excessive patellofemoral joint pressure and wear and tear to articular cartilage, surface fibrilation
- femoral anteversion, leg length discrepancy, flat foot wear, training
the intervention of chondromalacia patallae depends on ?
cause
patallare dislocation almost always happens to what side and in whom?
lateral side
women
lateral movement of the patella is counterbalanced by the?
why doe is dislocate on this side?
- vastus medialis
- -> lateral femoral condyles has a more anterior projection and a deeper slope for the larger lateral patellar facet providing further mechanical deterrant to lateral dislocation
what can i patella fracture be caused from
a direct blow to the knee or sudden action of the quadriceps
what is a transverse patellar fracture
fracture of the patella into 2 pieces from a powerful quad action
- proximal patellar fragment is pulled superiorly with the quads and the distal fragment remains with the patellar ligament
removal of the patella due to injuries such as a comminuted fracture
patellectomy
with a patellectomy, the quads have to exert about ___% more force to extend the leg
30-50%
