Knee joints Flashcards
(24 cards)
Describe the capsule in the knee joint
Capsule deficient anteriorly
- Sesamoid patella has tendons
- Tendons are outside joints
Has a synovium and many bursae
Name the 5 main ligaments in the knee joint and their general functions
Collateral (tibial and fibial), resist turning forces
Cruciate (ant and post), stabilise joint
Meniscofemoral (comes off post horn of lateral meniscus, ant and post ligament behind and infront of PCL)
Oblique popliteal (comes off popliteus tendon), strengthen back of joint
Arcuate, posterolateral stability around popliteus
Describe the 3 nerves that supply the knee joint
Femoral (from ant thigh)
Obturator (from med thigh)
Common fibular and tibial
Describe the blood supply of the arteries
Genicular arteries
Describe the 2 types of knee dislocation
Anterior dislocation (tibia moves anteriorly) Posterior dislocation (tibia moves posteriorly)
Condyles slip, patella separates from the rest of the knee
Describe the structure of the patella in the patella femoral joint
Attached to the the quadriceps tendon and patellar tendon
Patella itself has a lateral and medial surface.
Lateral surface is larger due to the greater lateral pull of the muscles
Lateral surface of patella is also larger on femur
Patella tendon attaches to tibial tuberosity
Patella apex at the bottom, base at the top
What is the function of the quadriceps tendon and muscle
Tendon and muscle extend leg
Describe how patella femoral dislocations occur
What is the normal functioning of the patella femoral region (muscles)
Normally, the vastus lateralis and intermedialis have a lateral pull
Vastus medialis counter this lateral pull => medially pull
If vastus medialis wastes away, patella gets pulled laterally => lateral dislocations for likely
What is the Q angle
What is the Q angle in males and females
Angle between quadriceps tendon and patella tendon in full extension
Females, 17
Males 14, due to females having a larger pelvis
What are the 5 situations that cause the Q angle to increase
Genu valgum Increased femoral anteversion External tibial torsion Lateral tibial tuberosity Tight lateral retinaculum (bands of fibrous fascia that pass over tendons)
Describe the structure of the tibial femoral surface of the knee joint
Fibular collateral ligament not attached to lateral meniscus
Tibial collateral ligament attached to medial meniscus => stability
Medial meniscus is C shaped, has ant and post horns
Lateral meniscus is more O shaped, has ant and post horns
Transverse vehicular ligament between ant horn of medial meniscus and ant of lateral meniscus => stabilise joint
Posterior cruciate comes post => ant => medial
Anterior cruciate comes ant => post => lateral
Coronary ligaments attach to menisci laterally to tibia => stability
Describe the function of the menisci
Fibrocartilage structures that
- Deepen articular surfaces of the tibia
- Shock absorbers
Menisci filled with synovial fluid, like a sponge
Describe the articulating surfaces of the femur, tibia and patella
Why are they shaped like this
Lateral and medial surface articulate with lateral and medial surface of the femur
The lateral posterior side of the femur is more rounded than the medial posterior side
Medial femoral condyle is curved, when you run out of lateral condyle when you extend your leg => 15 rotation
Rotation tightens collateral and cruciate => stability
Describe how the meniscus can tear
Can rip completely => bucket handle
Can flip over and become stuck in the middle of the knee joint => locked knees
Describe how to popliteus muscle relates to the knee joint
How does it relate to the arcuate ligament
What is innervated by
What is its function
Attaches to lateral condyle of femur and post horn of lateral meniscus from medial side of tibia
Inserts under the arcuate ligament
Unlocks the knee
Tibial nerve L4-S3
Name the ligaments found on the lateral side of the joint
What are their functions
Iliotibial tract, stabilise lateral knee
Quadriceps and patella tendon
Retinaculum of vastus lateralis comes under iliotibial and patella tendon, support anterior
Fibular collateral attaches to fibula and femur, lateral support
Popliteus comes from medial of tibia => femur, lateral support
Biceps femoris attaches from fibula, stabilise posterior
Name the ligaments found on the medial side of the joint
What are their functions
Tibial collateral attaches to tibial and femur, medial support, medial support
Retinaculum of vests medialis attaches from post femur to under the patella tendon, medial support
Pes anserinus (semitendinosus, sartorius, gracilis), medial support
Describe the 2 angles of the knee that can arise and why
Genu varum
- Lateral ligament weakens
- Tibia inwards
Genu algum
- Medial ligament weakens
- Tibia outwards, lateral compression
- Pes anserinus damage
Describe the route of the anterior and posterior cruciate ligaments
Anterior cruciate
-Ant of tibia from intercondyle area => post => lateral
Posterior cruciate
-Post of tibia from intercondyle area => ant => medial
What happens to the cruciates in extension and flexion
What is the function of the cruciates
How do you test for cruciate injuries
Extension
-Both are taut to lock the knee
Flexion
- ACL relaxed
- PCL taut
ACL prevents tibia from slipping forwards
PCL prevents tibia from slipping backwards
Test for CL injury by trying to displace tibia nand fibula
What is the unhappy triad
What is it caused by
Injury to ACL, MCL, medial meniscus
-Caused by over twisting taut ligaments
Describe the structure of the synovial membrane in the knee joint
Describe how fast structures in the synovium heal compared to structures outside the synovium
ACL, PCL in capsule but outside synovium
Alar fold ant to ACL
Synovial membrane surrounds both menisci
Structures outside synovium heal faster, have a blood supply
Name the 6 main bursa found in the knee joint and their location
Suprapatellar, 8cm above patella behind quadricep tendon
Prepatellar, infront of patella
Infrapatellar, below patella, ant and post of patella ligament
Anserine, separates anserinus from tibia
Popliteus, between popliteus and lat condyle
Gastrocnemius, between medial head of gastrocnemius and tibia
What are the symptoms of bursitis
Swelling
Redness
Pain
Location of swelling => which bursa is infected
