Lecture 6: Tissues under load 4

Question 1

what is a complex synovial joint?

Answer 1

when there is a simple joint plus extra structures

Question 2

what is a compound synovial joint?

Answer 2

when there is more than two bones at a joint

Question 3

what kind of joint is the knee?

Answer 3

a comound-complex synovial joint

Question 4

in joints, which is more common, angular or linear movement?

Answer 4

angular. linear movement would be the lateral sliding of bones which is not good

Question 5

what is the largest joint in the body?

Answer 5

the knee

Question 6

what are the complex features in the knee joint?

Answer 6

• shape of the contributing bones (condyles, fossa and trochlea)
• intracapsular and extracapsular ligaments
• tendons
• menisci

Question 7

which three bones form the knee joint?

Answer 7

tibia, femur and patella

Question 8

why isn’t the fibula part of the knee joint?

Answer 8

because it doesn’t contribute to the articulation of the knee

Question 9

why is the knee a compound joint?

Answer 9

because there are three articulating surfaces

Question 10

what are the three articulating surfaces in the knee joint that makes is compound?

Answer 10

2 are found between the condyles of the tibia and femur
- lateral tibio-femoral joint
- medial tibio-femoral joint
- patellar-femoral joint

Question 11

how is the patella a sesamoid bone?

Answer 11

because it isn’t attached to the femur by ligament, but instead sits in a trochlea

Question 12

what is the function of the trochlea?

Answer 12

to prevent the patella from sliding laterally or medially

Question 13

what is a meniscus?

Answer 13

like a rubber washer- a fibrocartilage ring that supports the femur

Question 14

what is the intercondylar eminence?

Answer 14

acts as a plug, sits in the fossa and allows rotation of the knee joint

Question 15

what is the intercondylar fossa?

Answer 15

the space between the condyles of the femur. it sits atop the intercondylar eminence and allows for movement of the femur and tibia anteriorly and posteriorly without moving them medially or laterally (linear movement prevented)

Question 16

rotation of the knee can only occur when it is?

Answer 16

flexed

Question 17

can your knee joint abduct and adduct?

Answer 17

lets bloody hope not

Question 18

flexion and extension of the knee is movement in the ____________ plane, and it is pivoting around the ______________ axis

Answer 18

sagittal, medial-lateral or transverse

Question 19

what are the adaptations made to the bone shape that allows for a larger angle of movement of the knee joint?

Answer 19

• curved ends of bones
• offsetting articulating surfaces (condyles ‘poke out’)

Question 20

what is the negative side effect of offsetting the articulating surfaces at a joint?

Answer 20

one articular surface is longer than the other and the joint would roll off

Question 21

what adaptation prevents the femur from rolling off of the tibia?

Answer 21

rolling and sliding anteriorly and posteriorly
- IF and IE is the adaptation that prevents medial and lateral sliding

Question 22

rotation of the knee is movement in the ____________ plane, and it is pivoting around the ______________ axis

Answer 22

transverse, superior-inferior

Question 23

what adaptation allows rotation of the knee joint?

Answer 23

the intercondylar eminence acting as a round pivot point for 360º rotation rather than just forwards and backwards movement

Question 24

approximately how much rotation in degrees do we get while sitting?

Answer 24

70º

Question 25

adduction and abduction of the knee would be movement in the ____________ plane, and would pivot around the ______________ axis

Answer 25

frontal, anterior-posterior

Question 26

ligaments are made out of _________ connective tissue

Answer 26

dense connective tissue

Question 27

the main purpose of ligaments is to?

Answer 27

distribute tensile loads to other structures within the joint, and limiting or controlling the limits of joint motion

Question 28

what movement do ligaments prevent in the knee?

Answer 28

abduction and adduction

Question 29

what are extracapsular ligaments?

Answer 29

ligaments that occur outside the articular capsule

Question 30

what are capsular ligaments?

Answer 30

they form the outer fibrous layer of the articular capsule

Question 31

what are intracapsular ligaments?

Answer 31

ligaments that are found inside the articular capsule

Question 32

list the two collateral ligaments of the knee

Answer 32

- Tibial (or medial) collateral ligament (joins femur to tibia) - fibular (or lateral) collateral ligament (joins femur to the fibula)

Question 33

the collateral ligaments only work...?

Answer 33

when the knee is in full extension. during flexion these ligaments are loose.

Question 34

what are the retinaculae?

Answer 34

fibrous connective tissue that stengthens the ligament and stabilises the patella in place, as the quads move the patella in multiple directions

Question 35

which ligament does knee adduction break?

Answer 35

fibular (or lateral) collateral ligament

Question 36

which ligament does knee abduction break?

Answer 36

tibial (or medial) collateral ligament

Question 37

what feature of the knee prevents adduction and abduction in the unwanted plane?

Answer 37

the condyles

Question 38

what are the intracapsular ligaments of the knee?

Answer 38

the cruciate ligaments: - anterior cruciate ligament - posterior cruciate ligament

Question 39

where are the cruciate ligaments of the knee attached?

Answer 39

to the inside of the articular capsule - the intercondylar fossa

Question 40

where are the attachments of the anterior cruciate ligament

Answer 40

attaches to the tibia anteriorly and the intercondylar fossa posteriorly

Question 41

where are the attachments of the posterior cruciate ligament

Answer 41

attaches to the tibia anteriorly and the intercondylar fossa anteriorly

Question 42

what movements does the anterior cruciate ligament resist in terms of the femur and tibia?

Answer 42

resists the posterior movement of the femur and the anterior movement of the tibia

Question 43

what movements does the posterior cruciate ligament resist in terms of the femur and tibia?

Answer 43

resists the anterior movement of the femur and the posterior movement of the tibia

Question 44

ligaments provide ________ stabilisation of the knee, whereas tendons and muscles provide _______ stabilisation of the knee

Answer 44

passive, active

Question 45

how are the collateral ligaments both extracapsular and capsular?

Answer 45

because they transition from being outside the articular capsule to being a part of the articular capsule, but aren't inside like the ACL and PCL.

Question 46

what are the four muscles of the quadriceps femoris?

Answer 46

- rectus femoris - vastus intermedius - vastus medius - vastus lateralis

Question 47

which muscle attaches to the patella ligament

Answer 47

none, its a ligament between the patella and the tibia

Question 48

where is the origin and insertion of the quadriceps?

Answer 48

origin is at the femur (unless it is rectus femoris, whose origin is at the ilium), insertion is at the patella.

Question 49

where are the insertions of the hamstring muscles?

Answer 49

biceps femoris = lateral side of the tibia and the head of the fibula semitendinosus = medial side of the tibia semimbranosus = medial side of the tibia

Question 50

what rotation does semitendinosus and semimembranosus contribute to if flexed alone?

Answer 50

medial or internal rotation

Question 51

what rotation does biceps femoris contribute to if flexed alone?

Answer 51

lateral or external rotation