Anatomy- Knee and Leg Flashcards
(38 cards)
What bones comprise the knee joint?
- Femoral condyles
- Tibial condyles
- Patella
What 3 articulations are formed by the knee joint?
- 2 femorotibial
- 1 femeropatellar
Is the fibula associated with the knee joint?
NO
What is the role of the fibula and what articulations does it make?
- Plays little role in weight bearing and is an important site for muscle attatchments and also stabilises the ankle.
- Articulates with tibia at tibiofemoral joint
What is the allignment of the femur on the tibia like and why is this important?
- Femur is diagonal whereas tibia is vertical
- There is a Q angle between the two
- Allows knee to be positioned under the hip and distributes weight evenly across knee
- Retains centre of gravity to midline
What does the obliquety of the femur depend on?
-Depends on angle of alignment normally around 126 degrees between neck and shaft of femur.
What degrees is the Q angle usually?
around 15
but is greter in females
How can Q angle be measured?
-By drawing line from ASIS to middle of patella then a vertical line through patella and tibial tuberosity and calculating angle between them.
What is genu varum?
- When Q angle is less than 17 degrees
- Tibia adducted with respect to femur
- Bow leg
What is genu valgum?
- When Q angle is more than 17 degrees
- Tibia abducted with respect to femur
- Knock knee
Describe the stability of the knee joint and what helps to provide it?
-Not very stable, most stable when extended
-Depends on: ligaments connecting femur and tibia
Strength of its surrounding muscles (and their tendons)
What are the inner articular ligaments and where are they?
- ACL
- PCL
- Cross each other obliquely in the centre of the knee
Which of the CL ligaments is stronger?
-Posterior
Where exactly are the ACL and PCL (origins and insertions)?
- ACL: attaches to ant. intercondylar region of tibia and travels superoposteriorly to attach to lat. femoral condyle.
- PCL: attaches to post, intercondylar regions of tibia and travels superoanteriorly to insert onto medial femoral condyle.
What is the function of the ACL?
- Prevents ant. displacement of the tibia on the femur
- Prevents hyperextension
What is the function of the PCL?
- Prevents post. displacement of the tibia on femur
- Prevents hyperflexion of knee
- Main knee stabiliser when weight bearing eg. walking down hill
What are the menisci?
-2 crescent shaped fibrocartilage joints between femur and tibia
Where are menisci thicker?
At external margins
What is the function of the menisci?
- Increase joint congruency
- Shock absorbing
- Distribute weight evenly
- Assist in locking mechanism
- Aid lubrication by facilitating movement of synovial fluid
What are meniscal tears and what may cause them?
- May be due to sports injury or degenerative changes
- Displaced cartilage can become trapped during knee movements (pain or locking)
What is a potential treatment for meniscus tears and a risk associated?
-Menisectomy (associated with development of osteoarthritis)
When may ACL damage occur and how can it be tested?
- When knee is hyperextended or force applied anteriorly
- Test: tibia can be pulled anteriorly on a fixed femur
When may PCL damage occur and how may it be tested?
- When landing on the tibial tuberosity with the knee flexed.
- Test: tibia can be pushed post. on a fixed femur
What muscles are involved in stabilising the knee joint and what is the mosst important?
- Quadriceps, hamstrings, sartorius, gracilis, IT tract
- Quads most important, building up that muscle can even compensate for ligament damage
