Knee Cont Flashcards
What are the 2 components of the synovial joint?
- External fibrous capsule
- Internal synovial membrane
Is the external fibrous capsule complete in the knee joint?
NO- incomplete where the popliteus tendon pierces it
What does the synovial membrane separate?
The inside of the joint into medial and lateral compartments
Infra-articular describes being within the ______
-Synovium
What does the synovium line?
Any part of the knee that is covered with cartilage
Posteriorly, the knee capsule is most defined, anteriorly it is not. What is continuous with the knee capsule anteriorly?
-The quadriceps tendon –> patella –> patellar ligament
act like the capsule
Describe the position of the cruciate ligament
Intracapsular yet extra articular
-Occupy a space within the external capsule BUT not within the synovial cavity
Are the menisci within the synovial cavity?
No
What is the suprapatellar bursa continuous with?
Synovial cavity
What are the 5 extracapsular ligaments of the knee?
- Patellar ligament
- Tibial Collateral Ligament (MCL)
- Fibular Collateral Ligament (LCL)
- Oblique Popliteal Ligament
- Arcuate Popliteal Ligament
This is the inferior part of the quadriceps tendon that runs to the tibial tuberosity
Patellar tendon
This is an extension of the vastus medialis muscle and the deep fascia
Medial patellar retincula
What is the lateral patellar retinacula an extension of?
Vastus lateralis
What are the roles of the medial and lateral patellar retinaculum?
- Contribute to joint capsule
- Maintain the alignment of the patella
- Keep the vertical ridge of the patella on the condylar groove
This ligament rises posterior to the medial condyle of the tibia and runs superolaterally to the lateral femoral condyle and blends with the capsule joint
Oblique popliteal ligament
What is the oblique popliteal ligament an extension of?
The semimembranosus muscle
This ligament arises from the posterior fibular head and passes superomedially over popliteus muscle
-spreads over the posterior surface of the knee joint
Arcuate popliteal ligament
What tendon goes the arcuate popliteal ligament spread over?
Tendon of popliteus muscle
What movement do the oblique and arcuate ligaments prevent?
Prevent hyperextension
What muscle is the arcuate ligament derieved from?
The biceps femorus tendon
Describe the Tibial Collateral Ligament (MCL)
-where does it run
- Broad and thick
- Runs from the medial epicondyle of the femur to the medial condyle of the tibia
When is the MCL taut?
- Full extension
- Tibial external rotation (Valgus stress- opening of the medial joint)
What movement does the MCL limit?
Lateral rotation of the tibia when the knee is in flexion
Some of the MCL fibers blend with the…
Medial meniscus
What ligament is stronger, the MCL or the LCL
LCL is stronger
Describe the Fibular Collateral Ligament (LCL)
- Thinner but stronger
- Runs from the lateral femoral epicondyle to the head of the fibula
Do the fibers of the LCL blend with anything?
NOPE
What movement does the LCL resist?
Varus stress
Opens up the space between the lateral condyles
When is the LCL taut?
- Full extension
- Internal rotation of the tibia
This muscle occupies the space between the LCL and the lateral menisucs
Popliteus muscle
What does the LCL sit between on the head of the fibula
The tendons of the biceps femorus long and short head
These structures always aintain contact between the femur and the tibia
Cruciate ligaments
How are the cruciate ligaments oriented?
-Obliquely and they wind around eachother in rotation
In knee flexion, _____ rotation is limited, while ____ roation is considerably more
Medial rotation is limited
-Lateral rotation is way more
What is the main purpose of the ACL? (3)
- Limits the femoral condyles from rolling in flexion
- Prevents posterior displacement of the femur on the tibia
- Prevents hyperextension
Describe the location of the ACL
- Arises in the anterior intercondylar area of the tibia
- Extends superioposterolaterally to the medial side of the lateral femoral condyle
Describe the purpose of the PCL
- Limits the femur from sliding forward on the tibia (anterior displacement)
- Limits the anterior rolling of the femoral condyles in extension
- Main stabilizer
This ligament joins the lateral meniscus to the PCL and the medial femoral condyle
Posterior Meniscofemoral ligament
What composes the meniscus
Fibrocartilage
Where do the meniscus sit and what is their job?
- Sit on the tibial plateau
- Their margins attach to the joint capsule of the knee
- Deepen the surface and absorb shock
Review!! What is the medial meniscus adherent to? How does this effect it?
The MCL
-Makes it less mobile that the lateral meniscus
What assist in the mobility of the lateral meniscus?
The contraction of the popliteus muscle
What is an “unhappy triad”
Tear in the... -ACL -MCL -Medial menisus (makes sense that the MCL and medial meniscus are town together bc they are connected)
What is critical for the strength of the knee joint?
-Strong musculature
What is the important role of the vastus medialis muscle (oblique muscles)
It combats the pull of the patella and keeps the patella in the groove of the femur
