Knee Flashcards
1
Q
the study of forces acting on moving bodies
A
dynamics
2
Q
tibiofemoral joint is what kind
A
modified hinge
3
Q
patellofemoral is what kind of joint
A
synovial plane
4
Q
the knee needs both ? and ?
A
stability and mobility
5
Q
which femoral condyle is bigger
A
medial
6
Q
which tibial plateau is bigger
A
medial
7
Q
tibial lateau slopes posteriorly how many degrees?
A
7-10 degrees
8
Q
the hardest form of CT
A
bone
9
Q
3 main functions of bone
A
framework
lever system
protects viscera
10
Q
compact bone is aka
A
cortical bone
11
Q
spongy bone is aka
A
cancellous bone
12
Q
Wolff’s law
A
the change in bone shape (form) to match function
13
Q
% turnover in cancellous bone
A
25%
14
Q
% turnover in cortical bone per year
A
3%
15
Q
normal anatomical angle of femur and tibia
A
valgus angle of 185 degrees
16
Q
angle greater than 185 is known as
A
genu valgus
17
Q
angle smaller than 175 degrees known as
A
genu varus
18
Q
bow legs
A
genu varum
19
Q
knocked knees
A
genu valgum
20
Q
how is weight distributed bilateral stance?
A
equally distributed between medial and lateral condyles
21
Q
how does weight bearing line shift during unilateral stance?
A
toward the medial side to account for smaller BOS below COM (at toes)
22
Q
the medial shift during unilateral stance does what to medial compartment
A
increases compressive forces
23
Q
The femur sustains compressive force of ????? times body weight when standingon one leg.
A
1.8 to 2.7
24
Q
The medial shift increases compressive stresses medially and ? laterally
A
increases tensile stresses laterally
25
genu valgum shifts WB line onto ? and ?
lateral compartment and and increases lateral compressive forces
26
The part outside the cells
• Almost the entire volume of the tissue
• Determines the function
• Contains mainly proteins and water
extracellular matrix
27
fibrillar component of CT has
collagen and elastin
28
interfibrillar component of CT has
water, glycoproteins and proteoglycans
29
- distribute joint loads over as large an area as
possible
– allow contact and movement between two bony surfaces with minimal friction and wear
main functions of?
cartilage
30
primary component of cartilage
water
31
joint cartilage is?
avascular
32
deepest portions of cartilage are fed by
capillaries from subchondral bone
33
the rest of the cartilage is fed by
diffusion
34
3 types of cartilage
hyaline
fibrocartilage
elastic
35
found in synovial joints
| extremely low friction
hyaline cartilage
36
repair material
higher friction than synovial joint cartilage
menisci
fibrocartilage
37
maintains shape of structures
| ex] ear
elastic cartilage
38
C shaped
medial menisci
39
shaped almost as a complete ring
lateral meniscus
40
the strong attachments of the menisci prevent them from being ? during ? of the tibiofemoral joint
squeezed out
| compression
41
the menisci allow for
greater contact area at the knee joint and less stress
42
attaches to MCL, PCL, ACL a little
medial meniscus
43
attaches to ACL, PCL, femur and popliteus
lateral meniscus
44
How is cartilaginous compressibility affected by the rate of loading?
with rapid loading, the cartilage becomes stiffer
45
force applied is the same over time
known as?
creep
46
molecules that attract/soak up water
– allow for nutrient delivery in connective tissue
– water imbibing swells tissues and gives them stiffness (like a water balloon)
glycosaminoglycans (GAG)
47
excessive compressive forces create
a shear force
48
obesity
repetitive loading
joint instability
rapid loading
mechanical factors that cause?
OA
49
what type of exercise increases fluid flow in and out of cartilage
ROM exercises
50
this type/intensity of exercise increases GAG count which increases tensile strength
moderate exercise
51
2 layers of joint capsule
```
stratum fibrosum (outside)
stratum synovium (inside)
```
52
poor vascularization
| rich innervation
stratum fibrosum
53
function: position and movement sense
stratum fibrosum layer
54
rich vascularization
| poor innervation
stratum synovium
55
function: produce synovial fluid
stratum synovium
56
you need rich innervation to?
sense proprioception
57
large and lax
knee joint
58
? in capsule important for stability
mechanoreceptors
59
synovial folds not absorbed during development
patellar plica
60
the fibrous joint capsule provides..?
passive support for the joint
61
capsular thickenings
ligaments
62
the MCL portions
superficial and deep
63
MCL resists
valgus force
| lateral rotation
64
MCL is tight in
full extension
65
LCL is joined by
biceps femoris muscle
66
LCL is NOT
a thickening of the capsule
67
resists varus force
| medial and lateral rotation
LCL
68
lig with high injury rate
ACL
69
resists anterior translation of tibia on femur
ACL
70
secondary role: provide rotary stability and resistance to valgus and varus stresses
ACL
71
both bundles of ACL are on slack when?
30 degrees of flexion
72
what muscles produce anterior shear
quads and gastroc
73
what muscles produce posterior shear
hamstrings when WB soleus
74
Shorter and has a greater cross-sectional area compared to ACL
PCL
75
resists valgus and varus forces and medial rotation of tibia
PCL
76
better at resisting in flexion
PCL
77
max posterior displacement of tibia occurs at
75-90 degrees
78
arcuate ligament resists
varus force
79
IT band attached where
gerdy's tubercle
80
taut regardless of hip or knee position
IT band
81
does IT band contract? why?
no, its more of a passive structure
82
Refers to the rotary movement of the
| bones in space during physiological joint motion
osteokinematics
83
flexion and extension in saggital plane
| around x-axis
osteokinematics
84
accessory motion
arthrokinematics
85
roll, slide, spin
arthrokinematics
86
Convex on fixed concave, motion?
opposite
87
concave on fixed convex, motion is?
same direction
88
PROM flexion
130-140 degrees
89
WB flexion ROM
160 degrees
90
gait ROM
60-70 degrees of flexion
91
PROM extension
5 degrees (hyperextension)
92
excessive knee extension- more than 5 degrees
genu recurvatum
93
one end of segment is free to move inspace
open chain
94
Both end of segment or set of segments are constrained
closed chain
95
When a force acts on an object it produces
deformation
96
Force per unit area
| – Dealing with tensile load
stress
97
Elongation per unit length in response totensile load
• Change in length/original length
• Expressed as %
strain
98
patella shifts ? during early flexion
medially
99
With more knee flexion, what happened to the patella?
compressive forces increase
100
Due to the oblique angle, the pull of the quads and the pull of the patellar tendon produce?
slight lateral force on patella
101
Angle between ASIS and midpoint of
patella and tibial
tuberosity and mid
patella
Q angle
102
normally 10-15 degrees
Q angle
103
the study of forces acting on a body at rest or equilibrium
statics
