Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Semester 2 FS Exam 8 > Knee Joint > Flashcards

Knee Joint Flashcards

1
Q

Knee Joint

A

largest and most complex joint
most stability comes from soft tissue, not bone
provides mobility for foot in space

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the two distinct articulations of the knee joint?

A

patellofemoral and tibiofemoral

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Net forces in knee joint during dynamic activities?

A

2 -3 x BW in normal gait
5 - 6 x BW in running and stair climbing
10 x BW in single leg standing in basketball

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Mechanical Axis

A

connection between hip and knee joint centers
line of action runs between hip and knee
shape defines which stresses the structure experiences
Bowing out = compression medially and tension laterally
norm = 3 degrees from vertical

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

The bigger the difference between the mechanical and anatomical axes ______ ???

A

the more compressive and tensile forces. if there is no difference between the two, the force will only be compressive.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Anatomical axis

A

runs along the shaft of the femur
normal = 6 degrees
lateral to the mechanical axis!!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Which ligament is very broad and is connected to the joint capsule?

A

MCL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Femur condyles (ovoid)

A

medial condyle larger and projects farther down, making the femur oriented laterally (femoral shaft obliquity) (anatomical axis)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

which condyle experiences more load?

A

medial femoral condyle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

which condyle is more in line with the shaft of the femur?

A

lateral

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

patellar surface

A

saddle shaped groove

lateral patellar surface is longer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

when are the MCL and LCL taut?

A

taut in extension, slack in flexion

tight ligaments = more joint stability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Tibial plateaus

A

Medial condyle/tibal plateau is 50% larger than the right and the cartilage is 3x thicker than the right.
Due to the mechanical axis, the medial condyle takes on more force than the lateral.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Patellomeniscal ligaments

A

enlargements of the joint capsule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

transverse ligament

A

located anteriorly, connects the menisci

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Medial meniscus attaches to ___ and ____

A

MCL and semimembranosus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

lateral meniscus attaches to ___ and ____

A

PCL and popliteus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

coronary ligaments

A

connect meniscus to tibia underneath

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

lateral vs medial meniscus shape

A 
lateral = almost a complete circle
medial = C shaped
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

menisci withstand ____

A

tension! resist stretch! do not withstand compression

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Function of menisci

A
  1. stabilize the joint - deepen articular surfaces
  2. shock absorption - improved congruency of joint surfaces
  3. force distribution within the joint
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

removing the menisci

A

increases contact area by 50%
coefficient of friction increases by 20% intrajoint
menisci = asymmetrical wedge-shaped

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

menisci vascularization

A

avascular structures, so they get their vascularization from the synovial membrane and joint capsule
meniscus has a free end (unattached) inside the joint, which helps synovial fluid move between the joint and decreases friction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Role of menisci during flexion

A

move/deform posteriorly with flexion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
role of menisci during extension
move/deform anteriorly with extension
26
Role of menisci in a normal knee during extension
Path of instantaneous center of rotation (ICOR): - moves posteriorly and then anteriorly - moves superiorly
27
which way does the path of ICOR move with flexion?
inferiorly
28
Knee without meniscus (ICOR)
ICOR is variable more glide in AP direction early degeneration of cartilage
29
A loss of the patella results in:
18-20% loss of motion | 48-50% loss of effectiveness of quads in extension
30
What does it mean that the patella is the least congruent joint in the body?
it has a large articular surface but the contact area is very limited during motion in different positions
31
Patella
anatomic pulley - friction reduction largest sesamoid bone in the body least congruent joint in the body improves mechanical advantage of quads
32
The odd facet makes up what percentage of the posterior aspect of the patella?
30%
33
Articular facets
slightly convex angle between medial and lateral facets is 138 degrees lateral facet larger than medial facet
34
At what angle of knee flexion is there the most congruency with respect to the articular surface of the patella and the femoral groove?
90 degrees knee flexion
35
Patella Tendon Moment Arm (PTMA)
largest MA of patellar tendon is at 45 degree angle | the best ability of the quads to produce torque is when the knee is at a 45 degree angle
36
Patella Alta
patella rides too high on femoral condyles | patellar groove is shallow and patella has a tendency to dislocate in lateral direction
37
Patella Baja
patella rides too low on femoral condyles due to patellar tendon shortening after surgery or injury MA and effectiveness of quads decreases
38
Which aspects of the facets are in contact with the femoral condyles in patella baja?
lateral part of lateral facet and odd facet. the result of this is that the forces are concentrated in a smaller area
39
Genu valgum
abnormal angulation of tibia away from midline leg mechanical axis is displaced laterally medial structures = tensile stress lateral structures = compressive stress
40
Knock kneed
genu valgum
41
Describe the load on the lateral compartment of the knee in genu valgum
more load on lateral compartment of knee between lateral condyle of femur and lateral tibial plateau articular cartilage is already thinner laterally, and thins due to compressive stress, increasing risk for OA
42
Genu varum
medial structure = compressive stress lateral structures = tensile stress abnormal angulation of tibia towards the midline leg mechanical axis is displaced medially MCL = slack LCL = tension
43
bow legged
genu varum
44
Genu recurvatum
tibia is tilted in the anterior direction tibial plateaus are not horizontal, so the load from the femur is on the anterior aspect of the tibia flexors of the knee are constantly active to control the passive load
45
Genu recurvatum
abnormal angulation of tibia anteriorly leg mechanical axis is displaced anterioly anterior structures = compression posterior structures = tension
46
excessive strain/torque on which structures in genu recurvatum?
excessive knee hyperextension excessive strain on ACL excessive extension torque during standing
47
typical Q angle
15 degrees | abnormal = >20
48
what is the Q angle influenced by?
location of patella knee joint alignment on frontal plane femoral and tibial torsions
49
Q angle in valgus
> 15 (greater Q angle = increased likelihood for patellar dislocation in lateral direction)
50
Q angle in varus
51
Patellar ligament
a continuation of the quad tendon
52
Bowstring effect
draw patella laterally | causes chondromalacia from chronic stress
53
Chondromalacia
type of OA inflammation and softening of cartilage involves bony structures
54
knee movements on sagittal plane
flexion and extension
55
knee movements on frontal plane
valgus and varus (about 5 degrees in each direction)
56
knee movements on transverse plane
IR/ER with knee at 90 degrees flexion
57
function of articularis genu muscle
moves bursa out of the way during knee extension
58
the synovial membrane gives rise to _______ and wraps around the ____ and ____
gives rise to multiple bursal structures and wraps around the ACL and PCL cruciate ligaments are outside the synovial membrane but inside the joint capsule
59
MCL
longer, wider, and closer to the capsule than the LCL | tight in extension, slack in flexion
60
two parts of MCL
anterior and posterior | anterior portion is tight in flexion
61
location of MCL
runs from medial femoral epicondyle to the tibia
62
location of LCL
from lateral femoral epicondyle to fibular head
63
function of LCL
resists varus stress/force and ER of tibia | tight in extension
64
function of MCL
resists valgus stress/force resists ER and IR of tibia resists anterior translation of tibia along with ACL
65
the MCL connects to which two structures?
medial meniscus and capsule
66
3 bands of the ACL
anteromedial intermediate posterolateral
67
origin/insertion of ACL
anterior intercondylar eminence of tibia to posterior part of the medial aspect of the lateral femoral condyle
68
functions of ACL
resists anterior tibial translation, hyperextension, and tibial IR resists anterior movement of the tibia on the femur (or posterior movement of the femur on the tibia)
69
when is the ACL tight?
in extension
70
when is the PCL tight?
in flexion
71
location of PCL
posterior intercondylar eminence to lateral aspect of medial femoral condyle
72
name the two bands of the PCL
anterolateral | posteromedial
73
functions of PCL
resists posterior tibial translation (posterior motion of tibia on femur) also resists flexion
74
common symptom after ACL injury
quad weakness | knee flexion is a protective mechanism for fear of reaching extension position by using quads
75
PCL and PTT
PCL resists PTT up to 90 degrees of knee flexion, and diminishes after that
76
PCL effect on PTT
PCL limits PTT until 90 degrees of flexion, and then decreases at higher flexion angles (does not help limit flexion in deep squat position)
77
Which ligaments limit hyperextension?
Arcuate popliteal, oblique popliteal, ACL
78
function of arcuate popliteal ligament
reinforces posterolateral capsule resists varus stress/impact helps LCL limits hyperextension
79
function of oblique popliteal ligament
reinforces posteromedial capsule resists valgus stress limits ER limits hyperextension
80
function of medial and lateral retinaculum
controls movement of the patella in the medial and lateral direction
81
ITB attachments
``` Iliopatellar band (causes lateral pull on patella) lateral tibial tubercle (Gerdy's tubercle) (assists ACL in resisting anterior translation of tibia on femur) (resists varus stress) ```
82
Which structures pull the patella laterally?
lateral retinaculum, ITB, iliopatellar band
83
Knee function stability
``` no bony stops to motion joint geometry change of menisci (1) passive restraint from ligaments (2) active muscles (3) compressive load ( more compressive load = more joint stability?) ```
84
motion of femur on tibia during closed kinetic chain
proximal on distal convex on concave roll and glide in opposite directions
85
motion of tibia on femur during open kinetic chain
distal on proximal concave on convex roll and glide in same direction
86
roll and glide during closed kinetic fhain
flexion: roll posteriorly and glide anteriorly extension: roll anterior and glide posterior menisci responsible for translation/glide that occurs during rolling
87
screw-home mechanism
15 degrees of tibial rotation occurs during final 30 degrees of knee extension. most of this rotation occurs during final 5 degrees of knee extension because of bony asymmetry (medial condyle projects farther than lateral condyle, creating IR) and because of ligament tension
88
open chain screw home mechanism
during terminal extension, ER of the tibia on the femur occurs
89
closed chain screw home mechanism
during terminal extension, IR of the femur on the tibia occurs
90
peak ability of muscles to do IR/ER of knee is when?
at 30-45 degrees of knee flexion. decreases beyond 45 degrees due to decreased muscle length
91
ER of knee
biceps femoris
92
IR of knee
semi ten and mem, sartorius, gracilis, popliteus
93
when do the quads produce maximum torque?
45 degrees of knee flexion (due to muscle length and muscle MA)

Semester 2 FS Exam 8 (1 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions