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Biomechanics 1 > Midterm 1 > Flashcards

Midterm 1 Flashcards

1
Q

what is kinematics?

A

movement of the body

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2
Q

what is kinetics?

A

forces or torques

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3
Q

what is linear kinematics and kinetics?

A

-translation
-all parts of body move parallel to and in the same direction

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4
Q

what is angular kinematics and kinetics?

A

-rotation
-body moves in circular path around axis or rotation

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5
Q

can arthrokinematics be angular and linear?

A

YES
-roll = angular
-slide = linear
-spin = angular

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6
Q

what is the MAX degrees of freedom in biomechanics?

A

3

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7
Q

what is closed packed position?

A

-max congruency
-capsule and ligaments tight
-accessory motion minimized
-some nuances for certain joints

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8
Q

what is open/loose packed position?

A

-less joint congruency
-capsule and ligaments lax
-accessor motion or joint play is greater

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9
Q

what is biomechnical stress?

A

-force/CSA
-internal resistance
-greater force or smaller CSA means more stress

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10
Q

what is strain?

A

-change in length

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11
Q

what is the toe region of the stress strain curve?

A

-collagen fibers have give
-not taut

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12
Q

what is the elastic region of the stress strain curve?

A

-stress and strain are linear
-change in length is proportional to applied force

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13
Q

what is the plastic region on the stress strain curve?

A

-tissue elongated beyond physiological range
-microscopic failure
-tissue permanently deformed

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14
Q

what is stiffness?

A

-stress/strain
-slope of line
-extent to which body resists deformation
-stiffer needs more force to change length

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15
Q

what is viscoelasticity?

A

-over time tissue may permanently deform if a stress is maintained
-creep

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16
Q

what is creep?

A

can change over time with a constant strech

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17
Q

do tissues become stiffer or more lax when load is applied quickly?

A

-stiffer
-protective mechanism

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18
Q

what are the series elastic components of passive length tension?

A

-attached in an end to end chain
-tendon, titin

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19
Q

what are the parallel elastic components of passive length tension?

A

-surround active elements
-epimysium, perimysium, endomysium
-fascia

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20
Q

can you directly measure force or tension in the clinic?

A

NO

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21
Q

can you measure force with EMG?

A

NO
-measures electrical activity

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22
Q

can you determine the type of muscle contraction with EMG?

A

NO

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23
Q

what is force?

A

-a push or pull that results from physical contact of two objects
-gravity
-any action that may change the state of rest or state of motion of the object to which it is applied

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24
Q

what are some types of forces?

A

-compression
-tension
-shear
-bending
-torsion
-combined loading

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25
Q

what are external forces?

A

-acting outside the system
-ground reaction forces, gravity, external load

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26
Q

what are internal forces?

A

-acting inside the system
-muscle, soft tissue tensile force, bony contact forces

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27
Q

what is newtons third law?

A

every action has an equal and opposite reaction

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28
Q

what are some factors that can affect muscle contractile force?

A

-actin/myosin
-angle
-energy stores
-CSA

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29
Q

what is a fusiform muscle?

A

-muscle fibers run parallel to one another to a central tendon
-can contract faster
-bicep, tricep

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30
Q

what is a pennate muscle?

A

-fibers approach central tendon obliquely
-more muscle fibers for given area
-less force delivered to tendon
-but more overall force produced

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31
Q

what is physiological cross sectional area? PCSA

A

-the area of the cross section of a muscle perpendicular to its fibers at the largest point
-larger in pennate muscles

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32
Q

in an eccentric contraction as velocity increases what happens to force?

A

-increases
-b/c fastly lowering load with the addition of gravity

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33
Q

in a concentric contraction as velocity increases what happens to force?

A

-decreses

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34
Q

in an isometric contraction what is velocity and force?

A

-no velocity

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35
Q

can you lower a heavier weight than you can lift?

A

YES

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36
Q

why is there DOMS in eccentric contractions?

A

-cross bridges are forcibly detached

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37
Q

what is newtons second law?

A

-F=ma
-produce acceleration in the direction of force

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38
Q

what is newtons first law?

A

-an object will remain at rest unless acted upon by an unbalanced external force

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39
Q

what is a scalar?

A

-quantities that have magnitide only
-mass, speed, distance, length, time, temp, volume, energy

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40
Q

what is a vector?

A

-quantities that have a magnitude and direction
-force, torque, weight, velocity, acceleration

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41
Q

what is mass?

A

-a measure of resistance to acceleration when a net force is applied

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42
Q

what is weight?

A

-the force of gravity acting on an object

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43
Q

what result do forces tend to cause?

A

-translation

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44
Q

what motion do torques tend to cause?

A

-rotation

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45
Q

what is torque?

A

force x moment arm

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46
Q

what is static equilibrium?

A

-all net forces and net torque must sum to 0

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47
Q

what are joint reaction forces?

A

-the force generated at the joint in response to forces acting on the joint
-no torque b/c no moment arm
-always goes through COR

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48
Q

what type of lever has the least mechanical advantage for the internal force?

A

3rd class

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49
Q

what type of lever has the most mechanical advantage for the internal force?

A

2nd class

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50
Q

how much weight does the tibia hold?

A

~10%

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51
Q

what is tibial torsion?

A

-distal end rotated ~10-20 degrees relative to proximal end
-can be reason for foot ER

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52
Q

what are the three main joints we will focus on in the foot?

A

-talocrural
-subtalar
-transverse tarsal joint

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53
Q

what makes up the subtalar joint?

A

-talus to calcaneus
-talus to navicular

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54
Q

what makes up the transverse tarsal joint?

A

-talus to navicular
-calcaneus to cuboid
-separates hind and midfoot

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55
Q

what is the hind foot?

A

calcaneus and talus

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56
Q

what is the midfoot?

A

-cuboid, navicular, cunieforms

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57
Q

what is the forefoot?

A

-metatarsals and phalanges

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58
Q

what are the two tibiofibular joints?

A

-proximal and distal

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59
Q

what is the proximal tibiofibular joint?

A

-head of fibula with lateral condyle of tibia
-sunovial joint
-some mvmt
-moves independantly of knee

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60
Q

what is the distal tibiofibular joint?

A

-medial distal fibula with fibular notch of tibia
-syndesmosis
-has interosseous ligament and interosseous membrane

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61
Q

what ligaments are at the distal tibiofibular joint?

A

anterior and posterior tibiofibular

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62
Q

what is a syndesmosis?

A

-immovable joint joined by connective tissue

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63
Q

why is the distal tibiofibular joint a syndesmosis?

A

need stable muscle attachment site

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64
Q

where is the concave porition of the talus?

A

lateral

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65
Q

where is the convex portion of the talus?

A

anterior

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66
Q

how much weight is transmitted though tibiotalar articulation?

A

90-95%

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67
Q

what are the lateral ligements of the ankle?

A

-anterior talofibular (ATF)
-posterior talofibular (PTF)
-calcaneofibular (CF)

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68
Q

what does the anterior talofibular ligament resist?

A

-INVERSION
-plantarflexion
-adduction
-ANTERIOR SLIDE OF TALUS

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69
Q

what does the posterior talofibular ligament resist?

A

-ABDUCTION
-inversion
-dorsiflexion
-posterior slide of talus

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70
Q

what does the calcaneofibular ligament resist?

A

-INVERSION
-dorsiflexion

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71
Q

what are the medial ligaments of the ankle?

A

-deltoid ligaments
-anterior tibiotalar
-posterior tibiotalar
-tibionavicular
-tibiocalcaneal

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72
Q

what does the anterior tibiotalar ligament resist?

A

-EVERSION
-dorsiflexion
-anterior talar slide

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73
Q

what does the posterior tibiotalar ligament resist?

A

-EVERSION
-dorsiflexion
-posterior talar slide

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74
Q

what does the tibionavicular ligament resist?

A

-EVERSION
-abduction
-anterior talar slide

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75
Q

what does the tibiocalcaneal ligament resist?

A

-EVERSION

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76
Q

what is the talocrural joint capsule?

A

-resinforce the weaker articular capsule
-synovial memebrane
-thicker laterallu
-connects talocrurual joint and calcaneus

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77
Q

what action occurs in the sagittal plane of the foot?

A

dorsi and plantarflexion

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78
Q

what action occurs in the frontal plane of the foot?

A

-inversion and eversion

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79
Q

what action occurs at the transverse plane of the foot?

A

-ab/adduction
-int/ext rot

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80
Q

what type of joint is the talocrural joint?

A

-hinge
- 1 DOF

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81
Q

what motions occur at the talocrural joint?

A

pornation/supination

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82
Q

what is supoination of foot?

A

-PF, add, inversion

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83
Q

what is pronation of the foot?

A

-DR, abd, eversion

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84
Q

what are the biggest motion at the talocrural joint?

A

PF/DF

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85
Q

in open chain dosriflextion what is the arthrokinematics?

A

-talus
-roll anterior
-slide posterior

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86
Q

in open chain plantarflexion what is the arthrokinematics?

A

-talus
-roll posterior
-slide anterior

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87
Q

what is the closed packed postiion of the ankle?

A

full dorsiflexion

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88
Q

in closed chain dorsiflexion what are ankle arthrokinematics?

A

-tib/fib
-roll and slide anterior

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89
Q

what are the talar calcaneal articulations?

A

-1 anterior articulation
-3 posterior articulations

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90
Q

what is the concavity of the posterior talarcalcaneal articulations?

A

-talus concave
-calcaneas convex

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91
Q

what is the concavity of the anterior talarcalcaneal articulations?

A

-talus convex
-calcaneaus concave

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92
Q

how many joint capsules are at the subtalar joint?

A

-2
-anterior and posterior

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93
Q

what is the most common location for joint mobilization at the subtalar joint?

A

-at posterior talarcalcaneal articulation

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94
Q

what are the ligaments of the subtalar joint?

A

-medial and lateral talocalcaneal
-cercical ligament

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95
Q

what do the talocalcaneal and cervical ligaments resist?

A

-all motions
-mostly INVERSION

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96
Q

what type of joint is the subtalar joint?

A

-plane
-1 DOF
-oblique axis or rotation
-curvlinear axis

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97
Q

in open chain subtalar eversion and inversion what bones moves on what?

A

calcaneus on talus

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98
Q

in open chain pronation what motions does the calcaneus move in?

A

-eversion and abduction
-minor dirsiflexion

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99
Q

in open chain pronation what motions does the calcaneus move in ?

A

-inversion and addcution
-minor plantarflexion

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100
Q

what is a curvilinear axis?

A

-no fixed axis
-a little more curve than linear translation
-joint moves in an arc that is perpendicular to oblique axis of rotation
-happens because of 3 articulations of calcaneous to talus

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101
Q

what happens in closed chain pronation at the subtalar joint?

A

-talus on calcaneus
-talus eversion and abduction and slight dorsiflexion

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102
Q

what happens in closed chain supination at the subtalar joint?

A

-talus on calcaneus and calcaneus on talus for inversion
-talus on calcaneus for adduction and minor plantarflexion

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103
Q

what are other names for the transverse tarsal joint?

A

-choparts joint
-midtarsal joint

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104
Q

what are the actions at the transverse tarsal joint?

A

pronation and supination

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105
Q

what type of joint does a talonavicular joint resemble?

A

ball and socket

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106
Q

does the talonavicular joint share a joint capsule?

A

-yes
-with the anterior subtalar capsule

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107
Q

what happens to the talus during weiaght bearing?

A

-depress and turn medially

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108
Q

what does the spring ligament support?

A

medial longitudinal arch

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109
Q

what does the calcaneal cuboid joint resemble?

A

-saddle joint
-more stable
-less motion
-has its own capsule

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110
Q

during pronation and suination what are the two main joints involvoed?

A

-subtalar
-transverse tarsal

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111
Q

how many DOF are at the transverse tarsal joint?

A

-complicated
-has both a longitudinal and oblique axis

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112
Q

what happens during open chain supination at the transverse tarsal joint?

A

-tibialis posterior spins navicular
-raise medial longitudinal arch
-navicular and cuboid move on talus and calcaneus

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113
Q

what happens during open chain pronation at the transverse tarsal joint?

A

-fibularis longus controls pronation
-navicular and cuboid move on talus and calcaneus

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114
Q

what happens during closed chain pronation at the transverse tarsal joint?

A

-subtalar pronates and GRF causes trasnverse tarsal joint to supinate

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115
Q

what happens during clsed chain supination at the trasnverse tarsal joint?

A

-subtalar supinates and lack of GRF cuases the transverse tarsal joint to pronate

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116
Q

what is the distal intertarsal joint?

A

-cuboid and navicular with cunieforms
-assists with pronation and supination
-stability across transverse arch

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117
Q

what is the keystone of the transverse arch?

A

-intermediate cunieform

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118
Q

what is another name for the tarsometatarsal joint?

A

-lisfranc joint

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119
Q

what happens at the tarsometatarsal joint?

A

-greatest moility at 1st, 4th, 5th joint
-only 1st has a joint capsule
-instability can lead to OA, pes planus, hallux valgus

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120
Q

what is the metotarsal phalangeal joint?

A

-2 DOF (DF, PF, ab/ad)
-2 sesmoid bones in FHB to increase leverage

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121
Q

what happens at the IP joints?

A

-hinge joint
-1 DOF (DF/PF)
-mobility greater proximally than distally

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122
Q

how many arches are there in the foot?

A

3

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123
Q

what is the importance of medial longitudinal arch?

A

-primary load bearing and shock absorbing
-assisted by plantar fascia
-role during standing is unclear
-when loaded and depressed high plantar fascia actitivy
-talus depressed during standing increasing calcaneal MT distance

124
Q

what is the keystone of the medial longitudinal arch?

A

talonavicular joint

125
Q

as the arch depresses what happens to the rearfoot?

A

-everts slightly

126
Q

what is pes planus?

A

-low arch
-weak tib posterior tendon, platar fasica, or sping ligament
-rearfoot eversion and depressed talus and navicular

127
Q

what are the two types of pes planus?

A

-rigid = congenital
-flexible = normal in NWB, flattens during WB

128
Q

what is the windlass effect?

A

-lengthening plantarfascia increased medial ongitudinal arch height
-if dont see arch raise could be sign of problem with plantar fascia

129
Q

what muscles contribute to dorsiflexion?

A

-TA
-EHL
-EHB

130
Q

what muscles contribute to plantar flexion?

A

-TP
-gastroc
-soleus
-FDL
-FHL

131
Q

what muscles contribute to inversion?

A

-TP
-TA
-FDL
-FHL
-EHL

132
Q

what muscles contribute to eversion?

A

-fibularis longus and brevis
-EDL

133
Q

what is the most commonly injured lateral ankle ligament?

A

ATF

134
Q

what test can you use to test for ATF integrity?

A

anterior drawer

135
Q

what test can you use to test for CF integrity?

A

talar tilt test

136
Q

what is the most common mechanism for a high ankle sprain?

A

-forceful external rotation of talus
-mortise comes apart

137
Q

what test can you use to test the integirty of the high ankle/ tibfib ligaments?

A

syndesmosis squeeze test

138
Q

which femoral condyle is larger?

A

medial

139
Q

what shape are the medial and lateral condyles of the femur?

A

convex

140
Q

what is the concavity of the trochlear groove?

A

-ML concave
-convex AP

141
Q

what is the concavity of the tibial condyles?

A

-medial concave
-lateral flat/convex

142
Q

which tibial condyle is larger?

A

medial

143
Q

what is the importance of the intercondylar eminence?

A

attachment sites for cruciate ligaments

144
Q

what is the concavity of the anterior patella?

A

convex in all directions

145
Q

what is the concavity of the posterior patella?

A

-vertical ridge
-medial and lateral facets
-odd facet on medial side

146
Q

what does the femur slant obliquely due to?

A

angle of inclination

147
Q

what is the normal absolute angle of the knee?

A

170-175

148
Q

what is normal and abnormal valgum?

A

-5-10 genu valgum normal
->15 abnormal

149
Q

what is abnormal genu varum?

A

-any varum
->0 degrees

150
Q

what are knee bursae?

A

-fluid filled sac that cushions bones, tendons, and muscles around the joint
-~14 in the knee

151
Q

what provides lateral knee stability?

A
  1. LCL
  2. IT band
  3. lateral patellar retinaculum
152
Q

what provides medial knee stability?

A
  1. MCL
  2. medial patellar retinaculum
  3. medial joint capsule thickened
153
Q

what provides anterior joint stability of the knee?

A
  1. medial and lateral patellar retinaculum
  2. patellar tendon
154
Q

what provides posterior joint stability?

A

-oblique ligament
-arcuate ligament

155
Q

what is the knee retinaculum?

A

-bands of fibrous tissue that support the patella
-insert on anteromedial and anterolateral tibia

156
Q

what wears away during knee OA?

A

-articular cartiledge

157
Q

what are the two types of cartidledge in the knee?

A

-menisci
-articular cartiledge

158
Q

what are the knee menisci?

A

-fibrocartilagenous structures
-create seats for convex femur
-outer 1/3 more vascularized and easier to heal

159
Q

. what anchors the menisci?

A

anterior and posterior horns
-anchor to the bone

160
Q

what are the 4 ligaments that stabilize the menisci?

A
  1. coronary
  2. transverse
  3. meniscofibular
  4. meniscofemoral
161
Q

what are the coronary ligaments?

A

-external edge of mensici to tibia
-loose

162
Q

what are teh transverse meniscal ligaments?

A

-stabilize two menisci together

163
Q

what are the meniscofibular ligaments?

A

-stabilize lateral menisci

164
Q

what are mensicofemoral ligaments?

A

-stabilize lateral mensici to femur

165
Q

what part of the mcl is attached to the medial meniscus?

A

-posteriomedial border

166
Q

what is the primary function of the menisci?

A

-reduce stress across knee by increasing surface area
-triple contact of joint

167
Q

what are the secondary functions of the menisci?

A

-stabilize joint in motion
-libricate
-proprioception
-guide arthrokinematics

168
Q

what is stress?

A

force/area

169
Q

how much compressive force acts at the tibia during walking realtive to body weight?

A

2.5-3x

170
Q

what type of joint is the knee/tibiofemoral?

A

condyloid

171
Q

how many degrees of freedom does the knee have?

A

-2 or 3
-flex/ext, IR/ER, valgus/varun
-valgus/varum is passive

172
Q

how does the axis rotate during knee flexion?

A

-posterior inferior

173
Q

when is the moment arm greatest for knee extensors?

A

-full extension

174
Q

when is the moment arm greatest for knee flexors?

A

-mid range

175
Q

at what range do we have the most and least knee IR/ER?

A

-most during 90 degrees of flexion (40-50)
-least in full extension

176
Q

what is the closed packed position of the knee?

A

full extension

177
Q

what muscles direct the toll and stabilize the menisci?

A

quads

178
Q

at what range does the screw home mechanism occur?

A

last 30 degrees of ROM

179
Q

what is the skrew home mechanism?

A

-lock knee into full extension
-open chain 10 degree tibia ER
-closed chain 10 degree femur IR

180
Q

what kind of motion is the screw home mechanism considered?

A

-conjunct
-b/c can not be separated from knee flex/ext

181
Q

what are the three factors driving the skrew home mechanism?

A
  1. medial condyle 30 degree lateral curve
  2. passive tension of ACL pulling towards its lateral origin
  3. slight lateral pull of vastus lateralis
182
Q

how does popliteus unlock the knee>

A

-femural ER
-tibial IR

183
Q

what is the arthorkinematics of knee IR/ER?

A

-SPIN
-cuases deformaiton and compression of menisci and femoral condyles

184
Q

what are the layers of the MCL?

A

-superficial layers connect to medial epicondyle, proximal tibia, and medial retincaulum
-deep fibers connect to medial mensicus and semimembranosus

185
Q

what are the functions of the MCL?

A

-resist valgus
-stabilize knee in extension
-resist extreme ER

186
Q

what is the importance of the LCL?

A

-short and vertical
-attaches to head of fibula
-half tensile strength of MCL
-blends with biceps femoris tendon
-no connectionto retinaculum or mensici

187
Q

what is the function of the LCL?

A
  1. resist varus
  2. stabilize in extension
  3. resist extreme IR and ER
188
Q

what is the attachment point of the ACL?

A

-medial portion of lateral condyle of femur

189
Q

how many bundles does the ACL have?

A

-2 collagen twist fibers
-anterior and posterior

190
Q

what is the primary function of the ACL?

A

-prevent anterior translation of tibia

191
Q

where is the ACL most taut?

A

full extension

192
Q

how does the ACL help with open chain extension?

A

-prevents excessive anterior slide

193
Q

what is an antagonist to the ACL?

A

-quads
-quads in extension side tibia anteriorly which stresses the ACL

194
Q

what is the attachment of the PCL?

A

-lateral aspect of the medial femoral condyle

195
Q

how many bundles does the PCL have?

A

-2 collagen twists
-anterior and posterior

196
Q

what is the primary function of the PCL?

A

-posterior translation of tibia

197
Q

where is PCL most taut?

A

-flexion
-90-120 degrees

198
Q

how does PCL help with flexion in open chain?

A

-prevent excessive posterior slide of tibia

199
Q

what is a PCL antagonist?

A

-hamstrings
-increasing flexion put more strains on PCL

200
Q

what is the MOI for MCL?

A

valgus

201
Q

what is the MOI for LCL?

A

varus

202
Q

what is the best knee angle for MCL and LCL stress tests?

A

-30 degrees

203
Q

what are the MOIs for the ACL?

A

-strong quad contrationw ith no flexion
-anterior tibial translation
-valgus collapse of the knee
-excessive rotation (especailly IR)
-hyperextension of knee

204
Q

what is protective to the ACL?

A

-hamstring activation decresses ACL stress
-especially at higher knee flexion

205
Q

how does valgus/varus stress affect ACL injury?

A

-ACL strain does not increase with greater valgus/varus
-in NWB no ACL strain with valgus and varus

206
Q

is there more ACL strain with IR or ER?

A

-2x more with IR
-bigger difference with WB

207
Q

what knee angle is the anterior drawer test at?

A

90 degrees

208
Q

what knee angle is the lachmans test?

A

30 dgerees

209
Q

what is the MOI of the PCL?

A

-trauma (usually occur with other structures)
-falling on flexed knee
-dashboard injury

210
Q

what is the clinical test for PCL?

A

-posterior drawer
-at 90 dgerres PCL provides 95% positioier translation support

211
Q

where is the greatest stress on the meniscus?

A

-posterior horns

212
Q

what is hoop stress?

A

-force dispersed along meniscal curvaturef

213
Q

what does damage to the meniscus especially the posterior horn cuase?

A

-decrease ability to withstand hoop stress
-less area avilable to disperse force

214
Q

what percentage of ACL involove mensical injury?

A

50%

215
Q

what is the MOI of meniscal injury?

A

-forceful axial rotation in WB
-axial torsion pinches and dislodges menisci

216
Q

what meniscus is more commonly injured?

A

-medial

217
Q

what are the muscles that flex the knee?

A

-hamstrings, sartorius, garcilis, popliteus, gastroc, plantaris

218
Q

what muscles extend the knee?

A

quads

219
Q

what muscles IR the knee?

A

popliteus, semimem, semit, sartorious, gracilis

220
Q

what muscles ER the knee?

A

biceps femoris

221
Q

for the knee extensors what is the greatest leverage point vs greatest torgue production?

A

-torque generally coincides with maximal leverage
-more torque in slightly more flexion

222
Q

what knee extensor has the larget PCSA?

A

vastus lateralis

223
Q

how much force can the quads produce?

A

6-9x BW

224
Q

what way do the quads bias line of pull?

A

-laterally 7-10 degrees

225
Q

what is the Q angle?

A

angle b/w line of pull of quads and patellar tendon
-13-15

226
Q

for the knee flexors where is the most leverage and most torque produced?

A

-most leverage a mid range
-most torque produced at extension b/c optimal cross bridges

227
Q

how does the soleus affect the knee?

A

-in closed chain pulls tibia posterior
-can protect ACL
-assists hamstrings in protecting ACL

228
Q

how does glut max affect the knee?

A

-in closed chain posteriorly
-thus anterior distplacment of tibia and stress on ACL

229
Q

what motions can the patella have?

A

-medial/lateral shift
-medial/lateral rotation
-medial and lateral shift

230
Q

during knee flexion how does the patella move?

A

moves inferioly

231
Q

during knee extension how does the patella move?

A

moves superioly

232
Q

in open chain knee motion what is the patellar arthrokinematics?

A

-tibia on femur
-patella slides on fixed femur

233
Q

in closed chain what is the patellar arthrokinematics?

A

-femur on tibia
-femur slides realtive to fixed patella

234
Q

what is the path of patellar contact with femur?

A

-flexion: superior pole mostly contacted
-mid range 90-60 greatest area of contact
-extension; inferior pole most contact

235
Q

at most contact how much of patella is in contact with femur?

A

-1/3

236
Q

what is the purpose of patella?

A

-more levaerage b/c increased MA

237
Q

what are the two reasons for poor PF joint tracking?

A
  1. malalignment
  2. maltracking
238
Q

is there more or less stress when patella is maltracking?

A

-more stress b/c decreased SA

239
Q

what can cause lateral tracking of patella?

A

-quads
-lateral retinaculum
-IT band b/c connected to lateral retinaculum

240
Q

what can cause medial patellar tracking?

A

-quads (VMO)
-medial retinacular fibers
-lateral facet of patella is steep and blocks lateral shift

241
Q

can therapist target WMO?

A

NO

242
Q

how does medial collapse effect PF tracking?

A

-natural genu valgum and/or poor hip NM control
-greater femoral adduction
-greater Q angle
-more lateral pull of quads
-patella moves laterally
-femoral IR

243
Q

what does the sacrospinous ligament form?

A

greater sciatic foramen

244
Q

what does the sacrotuberous ligament form?

A

lesser sciatic foramen

245
Q

what attaches at the ischial tuberosity?

A

–hamstrings
-adductor magnus
-sacrotuberous ligament

246
Q

what is the pubic symphasis?

A

-synasrthrosis: hyalin cartiledge
-resist shear stress
-collagen type I
-allows up to 2mm translation and slight rotation

247
Q

what bone makes up most of the acetabulum?

A

-ischium

248
Q

what bones makes up the least amount of the acetabulum?

A

-punic

249
Q

is the acetabular rim a complete circle?

A

no
-opening 60-70 degrees
-helps ROM but decreases stability

250
Q

what is the lunate surface of the acetabulum?

A

-where femoral head contacts the acetablum
-thickest superior and anterior
-covered with articular cartiledge
-aera with hight joint contact forces
-3x body weight

251
Q

what way does the femoral head project?

A

-medial, superior, anterior

252
Q

what way does the femoral shaft project?

A

-slight anterior convexity
-allows for bowing in WB

253
Q

where do the distal capsular ligaments of the hip attach?

A

-intertrochanteric line

254
Q

does the fovea have cartiledge?

A

-no
-no femoral head contact

255
Q

what is the angle of inclination?

A

-femoral neck and femoral shaft
-normal 125 degrees

256
Q

what is coxa vara?

A

-angle of inclination < 110
-congenital or injury caused
-can cause limb to be shorter

257
Q

what is coxa vlaga?

A

->135 angle of inclination
-often present with CP
-can cause limb to be longer

258
Q

does coxa valga or coxa vara have to produce more force for abduction?

A

-coxa valga
-less moment arm

259
Q

what is femoral torsion angle?

A

-in trasnverse plane
-angle b/w ML axis and femoral neck
-8-20 normal

260
Q

what os femoral anteversion?

A

->20
-causes in toeing
-b/w femur roates ER so tibia rotates IR to maintain congruency

261
Q

what is femoral retroversion?

A

-<8
-causes out toeing
-b/c femur rotates IR so tibia rotates Er to maintain congruency

262
Q

are we born with voxa valga and high angles of inclination?

A

-yes
-decreses with WB in development

263
Q

what is the importance of the ligamentum teres?

A

-in newborns provides stability and blood supply
-in adults unknown may aid in propriocenption

264
Q

where is ligamentum teres taut?

A

-flexion
-adduction
-IR

265
Q

what is the importance of the acetablular labrum?

A

-apex projects outward
-bends with articular cartiledge
-grips and provides suction seal for femur
-limited vascular supply

266
Q

what is the center edge angle?

A

-from vertical line and superior endge of acetabulum
-20-25 average

267
Q

what can low center edge angle cause?

A

-less contact aera
-greater joint stress
-higher superior dislocation risk

268
Q

what can high center edge angles cuase?

A

-increase chnace of impingement

269
Q

what is the acetabular anteversion angle?

A

-degree to which acetablum faces anteior
-20 normal

270
Q

what can high angles of anterversion cause>

A

-general instability
-higher risk for subluxation

271
Q

what does the transverse acetabular ligament connect?

A

-acetabular notch

272
Q

what is the importance of the hip joint capsule?

A

-very strong
-makes joint stable
-thicker anterior superior to assist in WB
-resistance fo end range flexion and extension

273
Q

what is the importance of the iliofemoral ligaments?

A

-resist extension, ER and slight abduction
-stringest lig
-resist hip extension in standing

274
Q

what is the importance of the pubofemoral ligament?

A

-maily resists abduction
-also resists extension and slight external rotation
-distal end fuses with Y ligament

275
Q

what is the importance of the ischiofemoral ligament?

A

-twisted fibers
-some IR resistance
-some extension and adduction resistance
-weakest of hip ligaments

276
Q

what is the closed packed position of the hip?

A

-extension, abd, IR
-where all hip ligaments are streched to increase stability

277
Q

what is the point where the hip has the most ocngruency?

A

-90 flex, abd, Er

278
Q

what is the arthrokinmeatics for open and closed chain hip flexion and extension

A

spin

279
Q

what are the arthrokinematics from hip open chian abduction?

A

-roll superior
-slide inferior

280
Q

what are the arthrokinemaitcs for hip open chain adduction?

A

-roll inferior
-slide superior

281
Q

what are the arthrokinematics for hip closed chain elecation/abduction?

A

-roll superior
-slide superior

282
Q

what are the arthrokinematics for hip closed chain drop/adduction?

A

-roll inferior
-slide inferior

283
Q

what are teh srthokinematics for hip open chain IR?

A

-roll anteiror
-slide posteiror

284
Q

what are the arthrokinematics for hip open chain ER?

A

-roll posterior
-slide antieor

285
Q

what are the hip arthrokinematics for hip closed chain IR?

A

-roll anteiror
-slide anterior

286
Q

what are the hip arthrokinematics for hip closed chain ER?

A

-roll posteior
-slide posterior

287
Q

what is the most prominent hip flexor in open chain?

A

-iliopsoas

288
Q

how does the iliopsaoas MA chnage with flexion and why?

A

-increase toward 90
-helps compensate for muscle length tension relatioship not being optimal

289
Q

why are abdominal muscles important to hip flexion?

A

-helps fix pelvis in posterior tilt so we can get stronger hip flexion

290
Q

what part of adductor magnus has good hip extension function?

A

-posterior

291
Q

is hip extensor torque greater with knee flexion or extension?

A

-extension b/c hamstrings not shortened so they have more passive tension in extension

292
Q

does hamstring moment arm increase or decrease with trunk flexion?

A

-increase

293
Q

does glut max moment arm increase or decrease with trunk flexion?

A

-decrease

294
Q

what is the JRF on teh hip during standing?

A

2.5x BW

295
Q

what angle is hip abductor torque the greatest?

A

10 degrees adduction
=where we are strongest in stance phase

296
Q

during running what is the advantage of earlier muscle activation?

A

-less hip adduction motion which is good
-less vlagus

297
Q

in what hip position is adductor magnus posterior fibers a good extender?

A

any position

298
Q

in what angle are teh other adductors of the hip good hio flexors?

A

0-40

299
Q

in what angle are the other adductors of the hip good extendors?

A

70-100

300
Q

where is glut med and min a stronger IR?

A

in 90 degrees of hip flexion

301
Q

where are glut max and piriformis good IR?

A

90 degrees of hip flexion

302
Q

where is obturator internus a good IR?

A

-never
-always an ER but worse moment arm in flexion

303
Q

where happens to obturator externus and quadratus femoris at 90 degrees of hip flexion?

A

-better ER

304
Q

how does hip ER torque change with hip flexion?

A

-ER slight increase in seated
-IR LARGE increase in seated b/c glut med and min much better IR in 90 degrees hip flexion

305
Q

do we have more hip rotation in prone or seated?

A

-prone
-seated limitation from capsule

Biomechanics 1 (1 decks)

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