Unit 4- Knee Flashcards
What type of joint is the knee joint?
What movements does it allow?
Hinge joint
Flexion and extension
The knee movements are accompanied by ____ and _____, in addition to:
Gliding
Rolling
Rotation about a vertical axis
When is the knee’s function most often at risk?
During hyperextension
Articulations of the knee:
2 femorotibial (between lateral and medial femoral and tibial condyles)
1 intermediate femoralpatellar (between the patella and femur)
Is the fibular involved in the knee joint?
No
Most important muscles in stabilizing the knee:
Quadriceps femoris
Particularly the fibers of the vastus lateralis
What does the stability of the knee joint depend on?
Strength and actions of surrounding muscle and tendons
Ligaments connecting the femur and tibia
What lines the internal surface of the articular cavity, not covered by articular cartilage, in the knee joint capsule?
Internal synovial membrane
Contents of the joint capsule
External fibrous layer
Internal synovial membrane
The fibrous layers attaches to the _______ Superiorly, just proximal to the:
Femur
Articular margins of the condyles
What does the joint capsule enclose posteriorly?
The condyles and the intercondylar fossa
The fibrous layer of the joint capsule has an opening posterior to the _____ _____ _____ to allow the _____ tendon to pass out of the joint capsule and attach to the ______
Lateral tibial condyle
Popliteus
Tibia
Inferiorly , the fibrous layer attaches to the margins of the:
Articular surface of the tibia (tibial plateau)
What are intimately applied to the fibrous capsule anteriorly?
Quadriceps tendon
Patella
Patellar ligament
What does the synovial membrane line?
The internal aspects of the fibrous capsule
What does the synovial membrane attach to?
The periphery of the patella and the edges of the cartilaginous menisci
The synovial membrane reflects from the ______ aspect of the joint anteriorly into the ____ ____, covering the ____ _____ and the ____ _____ ___ separating them for the articular cavity.
This creates a:
Posterior
Intercondylar region
Cruciate ligaments
Infrapatellar fat pad
Mediaian infrapatellar synovial fold
A vertical fold of synovial membrane that approaches the posterior aspect of the patella creating left and right femoral tibial articular cavities
Medial infrapatellar synovial fold
What do the fat filled lateral and medial alar folds cover?
The inner surface of the fat pads that occupy the space on each side of the patellar ligament internal to the fibrous layer
Where does the superapatellar bursa lie?
Superior to the patella (duh)
The knee cavity extends deep to the vastus lateralis as the:
Suprapatellar bursae
What forms the articular muscle of the knee?
Muscle fibers of the vastus intermedius
Muscle fibers of the vastus intermedius attach to the ___ _____.
What is its action?
Synovial membrane
Retracts the bursa during knee extension
What extracapsular ligaments strengthen the joint capsule?
Patellar ligament
Fibular (lateral) collateral ligament
Tibial (medial) collateral ligament
Oblique popliteal ligament
Arcuate popliteal ligament
Distal ligament to the quadriceps tendon
Patellar ligament
Pathway for the patella ligament
Passes from the apex and margins of the patella to the tibial tuberosity
The patellar ligament laterally receives aponeurosis expansions of the _____ ___ and _____.
These are important for:
Vastul lateralis and medialis (medial and lateral retinacula)
Maintaining the alignment of the patella
When are the collateral ligaments taut?
When are they lax?
In extension
In flexion- allows rotation of the knee
Pathway of the fibular (lateral) collateral ligament
Extends inferiorly from the lateral epicondyle of the femur
To the lateral surface of the head of the fibula
What tendon passes deep the the fibular (lateral) collateral ligament? What does this separate?
The tendon of the popliteus
The FCL from the lateral meniscus
The fibular collateral ligament splits what tendon?
Tendon of the biceps femoris
Tibial (medial) collateral ligament (TCL) pathway
Extends from the medial epicondyle of the femur
To the medial condyle and superior medial surface of the tibia
The deep fibers of the TCL are attach to the:
Medial meniscus
A reflected expansion of the tendon of semimembranosus that strengthens the joint capsule posteriorly
Oblique popliteal ligament
Pathway of the oblique popliteal ligament
Arises from the medial tibial condyle
Passes superolaterally to the central part of the posterior aspect of the joint capsule
What does the arcuate popliteal ligament strengthen?
The capsule posterolateral
Pathway of the arcuate popliteal ligament
Arises from the posterior aspect of the fibular head
Passes supero-medially over the popliteal tendon and attaches to the post surface of the knee joint
Intra-articular ligaments
Crusiate
Menisci
Popliteus
Cruciate ligaments join the ___ to the _____, crossing _____ the joint but outside the:
Femur
Tibia
Within
Articular cavity
How do the cruciate ligaments cross?
Obliquely
During medial rotation of the tibia on the femur, the cruciate ligaments do what?
This limits:
They wind around each other
Limits the amount of medial rotate to 10 degrees
Cruciate ligaments allof ____ of lateral rotation when the knee is flexed at >90 degrees
Approx 60 degrees
The cross over point of cruciate ligaments serves as an axis for:
Rotatory movements
Which cruciate ligament is weaker of the 2?
Anterior cruciate ligament
The anterior cruciate ligament (ACL) pathway
Extends superiorly posteriorly and laterally to the post part of the medial side of the lateral condyle of the femus
What does the ACL limit?
The post rolling of the femoral condyles on the tibial plateau during flexion converting it into rotation
The ACL prevents:
Post displacement of the femur on the tibia and hyperextension of the knee joint
Because of the ACL, when the joint is flexed, the tibia (CAN/CANNOT) be pulled anteriorly
Cannot
Pathway of the posterior cruciate ligament (PCL)
Arises from post. Condylar area of the tibia
Passes superiorly and anteriorly of the medial side of the ACL
Attaches to the ant part of the lateral surface of the medial condyle of the femur
The PCL limits what?
Anterior rolling of the femus on the tibial plateau during extension, converting it to rotation
The PCL also prevents anterior displacement of:
Or posterior displacement of:
The femur on the tibia
The tibia on the femur
Helps prevent hyperflexion of the knee joint
PCL function in the weight bearing flexed knee
It is the main stabilizing factor for the femur
Between ACL and PCL, which is under tension when knee is extended?
When knee is flexed?
ACL
PCL
Cresent-shaped plated of fibrocartilage on the articular surface of the tibia. They serve to deepen the joint surface and provide shock absorption
Menisci of the knee
Where are the menisci thicker?
At the outer margins
They taper to thin inner margins
Menisci are firmly attached where?
At their ends to the intercondylar area of the tibia
Where are the external margins of the Menisci attached?
To the fibrous joint capsule
Capsular fibers that attach the margins of the menisci to the tibial condyles
Coronary ligaments
Ligament that joins the anterior margins of the menisci together
Transverse ligament
C shaped meniscus that is broader posteriorly
Medial meniscus
Anterior horn of the medial meniscus attaches where?
To the anterior intercondylar area anterior to the attachment of the ACL
The posterior end of the medial meniscus attaches where?
To the posterior intercondylar area anterior to the attachment of the PCL
The medial meniscus is firmly adherent to the:
Deep surface of the tibial collateral ligament
Circular, smaller and more mobile meniscus
Lateral meniscus
What separates the lateral meniscus from the fibular collateral ligament?
The tendon of popliteus
What ligament joins the lateral meniscus to the PCL and the medial femoral condyle?
Posterior meniscofemoral ligament
How many bursa are around the knee joint?
Why?
At least 12
Most tendons run parallel to the bones and pull lengthwise across the joint during knee movements
Where are the subcutaneous prepatellar and infrapatellar bursae located?
What do they allow?
At the convex surface of the joint
Allow the skin to be able to move freely during knee movements
4 bursae that communicate with the articular cavity of the knee joint
Suprapatellar bursa (deep to the distal quads)
Popliteus bursa
Anserine bursa
Gastrocnemius bursa
Arteries supplying the knee joint that form the perigenicular anastomoses around the knee
Popliteal
Superior lateral, superior medial, middle, inferior lateral, inferior medial and descending genicular arteries
Descending branch of the lateral femoral circumflex artery
Anterior tibial recurrent branch of the tibial artery
Major blood supply to knee ligaments and synovial joint capsule
Middle genicular artery
Hilton’s law
The nerves supplying the muscles acting on the knee also innervate the joint
What nerves supply the anterior knee?
Articular branches of the femoral nerve
Nerve supply to the posterior knee
Tibial nerve
Nerve supply of the lateral aspect of the knee:
Common fibular nerve
Nerves that supply genicular articular branches
Obturator and saphenous nerves
Movements of the knee
Flexion and extension
Some rotation when also flexed
What causes the knee to “lock”?
When leg is extended, this causes medial rotation of the femur on the tibia, allowing weigh bearing without muscular exertion by the leg muscles
How to unlock the knee
The popliteus contracts rotating the femur lateral approx 5 degrees on the tibial plateau allowing flexion to occur