Lecture 18: Knee Joint

Question 1

how many articulations form the knee joint?

Answer 1

3 (medial femorotibial, lateral femorotibial, femoropatellar)

Question 2

femorotibial articulations

Answer 2

• medial femorotibial = medial condyle of femur to medial condyle of tibia
• lateral femorotibial = lateral condyle of femur to lateral condyle of tibia

Question 3

femoropatellar articulation

Answer 3

between femur and patella

Question 4

joint type

Answer 4

• shallow hinge type synovial joint
• unstable, but highly mobile
• susceptible to injury if hyperextended
• stabilized by extra and intra capsular ligaments, making it a well-built joint

Question 5

patellar ligament

Answer 5

distal part of quad tendon from patella to tibial tuberosity

Question 6

lateral and medial patellar retinaculum

Answer 6

• extensions of VLO and VMO that contribute to the joint capsule
• help keep patella aligned and stabilize knee joint

Question 7

collateral ligaments

Answer 7

• fibular (lateral) and tibial (medial)
• relaxed when knee is flexed
• taught when knee is extended
• run obliquely
• limit hyperextension and rotation

Question 8

fibular (lateral) collateral ligament

Answer 8

• attaches lat epicondyle of femur to lat surface of fibular head
• popliteus tendon prevents it from attaching to the lat meniscus
• limits ADD (varus)

Question 9

tibial (medial) collateral ligament

Answer 9

• attaches med epicondyle of femur to med prox tibia
• attached to medial meniscus
• limits ABD (valgus)

Question 10

oblique popliteal ligament

Answer 10

• attaches lat condyle of femur to tendon of semimembranosus (near the pes anserine)
• runs parallel to popliteus muscle

Question 11

arcuate popliteal ligament

Answer 11

• attaches head of fibula to posterior capsule
• forms opening in knee joint capsule for the tendon of the popliteus
• attaches to lat meniscus and lat epicondyle of femur

Question 12

cruciate ligaments

Answer 12

• anterior (ACL) and posterior (PCL)
• criss-cross within the intercondylar space of the joint capsule
• limit medial rotation at the knee
• keep femur and tibia aligned during flexion/extension

Question 13

anterior cruciate ligament (ACL)

Answer 13

• attaches ant intercondylar area of tibia to lat condyle of femur
• limits femur from sliding posteriorly
• limits tibia from sliding anteriorly
• opposes hyperextension of the knee

Question 14

posterior cruciate ligament (PCL)

Answer 14

• attaches post intercondylar area of tibia to medial condyle of femur
• limits femur from sliding anteriorly
• limits tibia from sliding posteriorly
• opposes hyperflexion of the knee

Question 15

menisci

Answer 15

• medial and lateral

- fibrocartilage wedges that act as cushions and create a lip to the shallow sockets of the tibia

Question 16

coronary ligaments

Answer 16

attach menisci to edge of tibial condyles

Question 17

transverse ligament

Answer 17

interconnects the anterior surface of the menisci across the intercondylar space

Question 18

why does the medial meniscus have limited mobility?

Answer 18

it is attached to the medial collateral ligament and the intercondylar space

Question 19

why is the lateral meniscus more mobile than the medial?

Answer 19

• it is attached to the popliteus tendon and medial condyle of femur by the posterior meniscofemoral ligament
• minimal attachment allows for more mobility

Question 20

knee lock

Answer 20

• when the knee is fully extended, the femur medially rotates into the condyles of the tibia to lock the knee
• to unlock the knee before flexion, the popliteus muscle laterally rotates the femur
• this gives the knee another measure of stability
• during most of stance phase during walking