Flashcards in Lecture: Lower Limb 2: The Knee Joint Deck (18):
Which articulations are there at the knee joint?
2 femorotibial (medial and lateral)
fibula not associated with the knee joint
what movements are possible at he knee joint?
Medial/Lateral rotation (when knee flexed at 90 degrees)
What happens as the knee extends?
as it approaches full extension, femur undergoes a few degrees of medial rotation of the tibia
locks the knee in place
unlocked by the popliteus muscle
what increases congruency at the tibial plateau
2 c-shaped wedges of fibrocartilage - the medial and lateral menisci
functions of the menicsci?
increase joint congruency
even distribution of weight
assist in the locking mechanism
external edges attach to fibrous capsule of the joint
How do meniscal tears arise and what is the consequence?
common sports/degenerative injury
displaced cartilage can become trapped during knee movements
can be painful/result in knee locking
damage is associated with osteoarthritis
What features contribute to the stability of the knee joint?
the surrounding muscles
Describe the posterior cruciate ligament (PCL)
attaches to posterior intercondylar region of tibia and ascends supero-anteriorly to insert on medial femoral condyle
prevents posterior dislocation of tibia on femur
supports weight walking downhill
Describe the anterior cruciate ligament (ACL)
attaches to anterior intercondylar region of tibia and ascends supero-posteriorly to attach to lateral femoral condyle
prevents anterior displacement of tibia on femur
Describe the Tibial (medial) collateral ligament
attached to medial meniscus
prevents abduction of leg at knee
Describe the Fibular (lateral) collateral ligament
NOT attached to lateral meniscus
prevents adduction of leg at knee
what is the unhappy triad of knee injury?
Torn Medial Meniscus
Torn Tibial (medial) collateral ligament
What typically causes the unhappy triad knee injury?
Excessive lateral twisting of flexed knee
or blow to lateral side of extended knee
Which muscles are the main stabilisers of the knee?
Where are the bursae of the knee located?
Pre-patellar bursae - superficial to knee
Deep and superficial infrapatellar bursae - just inferior to knee
common injuries to the knee joint?
bony fractures of any of the 3 bones involved
dislocations of the patella or even whole knee joint
Why are patellar dislocations more common in females than males?
Greater angle of femur due to wider, shallower hips
full of quads more horizontal