B6.047 Hip, Knee, and Ankle Joints + Erect Stance and Walking Gait

Question 1

only motion in a healthy ankle joint

Answer 1

dorsiflexion

plantarflexion

Question 2

where do eversion and inversion occur?

Answer 2

joints intrinsic to the foot

Question 3

acetabulum

Answer 3

deep, bony socket
makes hip a very stable joint
surrounded by a soft tissue “o ring’ or ‘gasket’ to make it deeper

Question 4

where is the head of the femur

Answer 4

NOT on the shaft

on the femoral neck

Question 5

what is the “Q” angle

Answer 5

axis of femoral shaft is not aligned with gravity in the anatomical position
neck of femur is inclined about 120 deg with respect to the shaft
this creates an angle between the femoral shaft and the vertical line of gravity (the Q angle, about 18 deg)

Question 6

what gender has a larger Q angle

Answer 6

female

pelvis is wider

Question 7

where is bone density the greatest in hip joints

Answer 7

along lines of gravitational load

Question 8

what is the iliofemoral ligament

Answer 8

thickest and strongest ligament in the body
thickening in the hip joint capsule that is named as a ligament
keeps trunk from flopping backwards

Question 9

blood supply to the hip joint

Answer 9

retinacular arteries that stretch across the neck, sending twigs to the femoral head

Question 10

most common hip injury in elderly

Answer 10

fracture of femoral neck
due largely to osteoporosis
retinacular blood vessels are highly susceptible to injury

Question 11

most common hip complaints

Answer 11

OA
bursitis
multiple bursae situated around the hip joint including the greater trochanter

Question 12

tuberculosis infection of the spine

Answer 12

can infiltrate the hip joint cavity via the capsule of the iliospsoas muscle, where it communicated with bursae and the joint cavity

Question 13

patella

Answer 13

floating bone that serves as a pulley and an attachment site for tendons and ligaments at the knee

Question 14

shape of femoral condyles

Answer 14

not perfectly circular

important for knee joint integrity (or laxity)

Question 15

what leg bone receives the weight of the upper body

Answer 15

tibia alone

fibula not part of the knee joint

Question 16

upper surface of tibial condyles

Answer 16

shallow depressions

receive femoral condyles

Question 17

are the articular surfaces in the knee joint complex?

Answer 17

yup

Question 18

can the articular surfaces in the knee joint be easily summarized?

Answer 18

nope

Question 19

functions of the menisci

Answer 19

wafers of fibrocartilage on the tibial plateau

help center condyles of femur on tibia

Question 20

1st line of defense to help create a stable knee joint

Answer 20

deep investing fascia of the thigh (fascia lata)

sleeve of dense connective tissue including the posterior and popliteal fascia

Question 21

lateral and medial patellar retinacula

Answer 21

major thickenings of fascia that extend from the thigh across the knee to anchor into the crural fascia

Question 22

fibular collateral ligament

Answer 22

stands apart from the joint capsule

attaches to lateral femoral condyle and head of fibula

Question 23

thickenings in knee joint capsule

Answer 23

anterior
-patellar ligament
intrinsic
-tibial collateral ligament
-oblique popliteal ligament

Question 24

what is the intrinsic joint capsule

Answer 24

stabilizes the posterior knee
dense, tough covering
deep to popliteal structures

Question 25

tibial collateral ligament

Answer 25

attaches to medial epicondyle and medial tibia | attaches to medial meniscus, making it a part of the joint capsule

Question 26

bursae in the synovial space

Answer 26

suprapatellar prepatellar infrapatellar

Question 27

location of cruciate ligaments

Answer 27

outside the synovial space but within the fibrous joint capsule named for their tibial attachments

Question 28

function of PCL

Answer 28

resist forward displacement of the femur off of a fixed tibia when in flexion

Question 29

function of ACL

Answer 29

resists backward displacement of a femur off of a fixed tibia when in extension

Question 30

can ACL and PCL resist blows from the side?

Answer 30

no lol | poorly positioned

Question 31

motions that can occur at the knee joint

Answer 31

flexion-extension medial-lateral rotation gliding-sliding

Question 32

when during the gait is the femur fixed with a mobile tibia

Answer 32

swing phase

Question 33

what happens during the last few degrees of leg extension during swing phase

Answer 33

lateral spin of the tibia on a fixed femur

Question 34

difference in femoral condyle sizes

Answer 34

articular cartilage of the medial femoral condyle reaches further forward than the corresponding lateral cartilage 1 cm extra room

Question 35

when is the knee joint more stable?

Answer 35

during extension ligaments are tighter during extension looser joint would be more susceptible to injury (flexed)

Question 36

what is locking the knee?

Answer 36

resting femur onto tibia not using any muscles very little energy required in this position due to stability of joints

Question 37

how do you unlock your knee joint?

Answer 37

shorten fibers of popliteus muscle when standing on a fixed tibia femur rotates laterally condyles of the femur spin on top of the tibia

Question 38

function of healthy ankle joint

Answer 38

flexion and extension only no medio-lateral or side to side motion dozens of ligaments surround the joint to stabilize and resist side to side motion

Question 39

where does side to side motion in the foot occur

Answer 39

sub talar joint (distal to ankle joint) | inversion and eversion occur here due to smooth upper surface of calcaneous

Question 40

overlooked function of the interosseous membrane

Answer 40

stabilization of the ankle joint

Question 41

most commonly injured joint in the body

Answer 41

ankle | usually due to excessive inversion injury involving fibular ligaments

Question 42

why aren't there ligament tears in the medial ankle as often?

Answer 42

deltoid ligament is so strong that the medial malleolus typically breaks instead of the ligament tearing

Question 43

ankle sprain

Answer 43

abnormal loads that cause excessive side to side ankle movements can tear collateral ligaments, resulting in a sprain

Question 44

ankle fracture

Answer 44

high velocity or overly powerful blows that involve twisting forces at the ankle lead to fracture, including avulsion of the lateral malleolus

Question 45

pott's fracture

Answer 45

common athletic injury distal fibula snaps a few centimeters above the inferior tibiofibular joint in severe eversion injury, medial malleolus is avulsed

Question 46

axis of standing posture

Answer 46

axis of knee joint is behind the hip joint trunk center of mass is in front of the knee when standing in a knee locked posture, the weight of the upper body acts to keep the knee joint stable

Question 47

why do humans often stand shifted onto one hip

Answer 47

minimize effort can stand on their ligaments with very little muscle activity tightening of iliotibial tract of the opposite thigh is one way to do this unloaded limb maintains balance but does little active work

Question 48

picture George's gait

Answer 48

lol

Question 49

what % of the gait is a double foot stance

Answer 49

60% stance phase | 40% swing phase (1 foot off the ground)

Question 50

ground reaction

Answer 50

generated to propel body mass forward | lengthen trailing limb to generate a pushing force by flexing the ankle and big toe

Question 51

max walking speed

Answer 51

6 mph 3 mps running gait needed to exceed this

Question 52

why does the biceps femoris contract before heel strike

Answer 52

to slow down the limb

Question 53

effect of high heels

Answer 53

change gait extreme plantar flexion requires compensation shoulders are pulled back with increased spinal curvature ( ass out ladies)

Question 54

what determines gait width

Answer 54

femoral inclination angle | places human knees close together, angle smaller in females

Question 55

function of gluteus medius and minimum

Answer 55

controlled pelvic tilt on unsupported side during normal gait

Question 56

Trendelenburg sign

Answer 56

hip drop on the unsupported side caused by a loss of hip abductors on the supported side (drop is opposite side of injury)

Question 57

pelvic rotation in gait

Answer 57

critical component | reduces side to side displacement of mass

Question 58

running gait

Answer 58

leading limb fully flexed at the hip | both feet off the ground

Question 59

most powerful ground reaction

Answer 59

spine has to be horizontal to the ground | similar to 4 footed vertebrates