Midterm 1 Flashcards
(305 cards)
1
Q
what is kinematics?
A
movement of the body
2
Q
what is kinetics?
A
forces or torques
3
Q
what is linear kinematics and kinetics?
A
-translation
-all parts of body move parallel to and in the same direction
4
Q
what is angular kinematics and kinetics?
A
-rotation
-body moves in circular path around axis or rotation
5
Q
can arthrokinematics be angular and linear?
A
YES
-roll = angular
-slide = linear
-spin = angular
6
Q
what is the MAX degrees of freedom in biomechanics?
A
3
7
Q
what is closed packed position?
A
-max congruency
-capsule and ligaments tight
-accessory motion minimized
-some nuances for certain joints
8
Q
what is open/loose packed position?
A
-less joint congruency
-capsule and ligaments lax
-accessor motion or joint play is greater
9
Q
what is biomechnical stress?
A
-force/CSA
-internal resistance
-greater force or smaller CSA means more stress
10
Q
what is strain?
A
-change in length
11
Q
what is the toe region of the stress strain curve?
A
-collagen fibers have give
-not taut
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
13
Q
what is the plastic region on the stress strain curve?
A
-tissue elongated beyond physiological range
-microscopic failure
-tissue permanently deformed
14
Q
what is stiffness?
A
-stress/strain
-slope of line
-extent to which body resists deformation
-stiffer needs more force to change length
15
Q
what is viscoelasticity?
A
-over time tissue may permanently deform if a stress is maintained
-creep
16
Q
what is creep?
A
can change over time with a constant strech
17
Q
do tissues become stiffer or more lax when load is applied quickly?
A
-stiffer
-protective mechanism
18
Q
what are the series elastic components of passive length tension?
A
-attached in an end to end chain
-tendon, titin
19
Q
what are the parallel elastic components of passive length tension?
A
-surround active elements
-epimysium, perimysium, endomysium
-fascia
20
Q
can you directly measure force or tension in the clinic?
A
NO
21
Q
can you measure force with EMG?
A
NO
-measures electrical activity
22
Q
can you determine the type of muscle contraction with EMG?
A
NO
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
24
Q
what are some types of forces?
A
-compression
-tension
-shear
-bending
-torsion
-combined loading
25
what are external forces?
-acting outside the system
-ground reaction forces, gravity, external load
26
what are internal forces?
-acting inside the system
-muscle, soft tissue tensile force, bony contact forces
27
what is newtons third law?
every action has an equal and opposite reaction
28
what are some factors that can affect muscle contractile force?
-actin/myosin
-angle
-energy stores
-CSA
29
what is a fusiform muscle?
-muscle fibers run parallel to one another to a central tendon
-can contract faster
-bicep, tricep
30
what is a pennate muscle?
-fibers approach central tendon obliquely
-more muscle fibers for given area
-less force delivered to tendon
-but more overall force produced
31
what is physiological cross sectional area? PCSA
-the area of the cross section of a muscle perpendicular to its fibers at the largest point
-larger in pennate muscles
32
in an eccentric contraction as velocity increases what happens to force?
-increases
-b/c fastly lowering load with the addition of gravity
33
in a concentric contraction as velocity increases what happens to force?
-decreses
34
in an isometric contraction what is velocity and force?
-no velocity
35
can you lower a heavier weight than you can lift?
YES
36
why is there DOMS in eccentric contractions?
-cross bridges are forcibly detached
37
what is newtons second law?
-F=ma
-produce acceleration in the direction of force
38
what is newtons first law?
-an object will remain at rest unless acted upon by an unbalanced external force
39
what is a scalar?
-quantities that have magnitide only
-mass, speed, distance, length, time, temp, volume, energy
40
what is a vector?
-quantities that have a magnitude and direction
-force, torque, weight, velocity, acceleration
41
what is mass?
-a measure of resistance to acceleration when a net force is applied
42
what is weight?
-the force of gravity acting on an object
43
what result do forces tend to cause?
-translation
44
what motion do torques tend to cause?
-rotation
45
what is torque?
force x moment arm
46
what is static equilibrium?
-all net forces and net torque must sum to 0
47
what are joint reaction forces?
-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
48
what type of lever has the least mechanical advantage for the internal force?
3rd class
49
what type of lever has the most mechanical advantage for the internal force?
2nd class
50
how much weight does the tibia hold?
~10%
51
what is tibial torsion?
-distal end rotated ~10-20 degrees relative to proximal end
-can be reason for foot ER
52
what are the three main joints we will focus on in the foot?
-talocrural
-subtalar
-transverse tarsal joint
53
what makes up the subtalar joint?
-talus to calcaneus
-talus to navicular
54
what makes up the transverse tarsal joint?
-talus to navicular
-calcaneus to cuboid
-separates hind and midfoot
55
what is the hind foot?
calcaneus and talus
56
what is the midfoot?
-cuboid, navicular, cunieforms
57
what is the forefoot?
-metatarsals and phalanges
58
what are the two tibiofibular joints?
-proximal and distal
59
what is the proximal tibiofibular joint?
-head of fibula with lateral condyle of tibia
-sunovial joint
-some mvmt
-moves independantly of knee
60
what is the distal tibiofibular joint?
-medial distal fibula with fibular notch of tibia
-syndesmosis
-has interosseous ligament and interosseous membrane
61
what ligaments are at the distal tibiofibular joint?
anterior and posterior tibiofibular
62
what is a syndesmosis?
-immovable joint joined by connective tissue
63
why is the distal tibiofibular joint a syndesmosis?
need stable muscle attachment site
64
where is the concave porition of the talus?
lateral
65
where is the convex portion of the talus?
anterior
66
how much weight is transmitted though tibiotalar articulation?
90-95%
67
what are the lateral ligements of the ankle?
-anterior talofibular (ATF)
-posterior talofibular (PTF)
-calcaneofibular (CF)
68
what does the anterior talofibular ligament resist?
-INVERSION
-plantarflexion
-adduction
-ANTERIOR SLIDE OF TALUS
69
what does the posterior talofibular ligament resist?
-ABDUCTION
-inversion
-dorsiflexion
-posterior slide of talus
70
what does the calcaneofibular ligament resist?
-INVERSION
-dorsiflexion
71
what are the medial ligaments of the ankle?
-deltoid ligaments
-anterior tibiotalar
-posterior tibiotalar
-tibionavicular
-tibiocalcaneal
72
what does the anterior tibiotalar ligament resist?
-EVERSION
-dorsiflexion
-anterior talar slide
73
what does the posterior tibiotalar ligament resist?
-EVERSION
-dorsiflexion
-posterior talar slide
74
what does the tibionavicular ligament resist?
-EVERSION
-abduction
-anterior talar slide
75
what does the tibiocalcaneal ligament resist?
-EVERSION
76
what is the talocrural joint capsule?
-resinforce the weaker articular capsule
-synovial memebrane
-thicker laterallu
-connects talocrurual joint and calcaneus
77
what action occurs in the sagittal plane of the foot?
dorsi and plantarflexion
78
what action occurs in the frontal plane of the foot?
-inversion and eversion
79
what action occurs at the transverse plane of the foot?
-ab/adduction
-int/ext rot
80
what type of joint is the talocrural joint?
-hinge
- 1 DOF
81
what motions occur at the talocrural joint?
pornation/supination
82
what is supoination of foot?
-PF, add, inversion
83
what is pronation of the foot?
-DR, abd, eversion
84
what are the biggest motion at the talocrural joint?
PF/DF
85
in open chain dosriflextion what is the arthrokinematics?
-talus
-roll anterior
-slide posterior
86
in open chain plantarflexion what is the arthrokinematics?
-talus
-roll posterior
-slide anterior
87
what is the closed packed postiion of the ankle?
full dorsiflexion
88
in closed chain dorsiflexion what are ankle arthrokinematics?
-tib/fib
-roll and slide anterior
89
what are the talar calcaneal articulations?
-1 anterior articulation
-3 posterior articulations
90
what is the concavity of the posterior talarcalcaneal articulations?
-talus concave
-calcaneas convex
91
what is the concavity of the anterior talarcalcaneal articulations?
-talus convex
-calcaneaus concave
92
how many joint capsules are at the subtalar joint?
-2
-anterior and posterior
93
what is the most common location for joint mobilization at the subtalar joint?
-at posterior talarcalcaneal articulation
94
what are the ligaments of the subtalar joint?
-medial and lateral talocalcaneal
-cercical ligament
95
what do the talocalcaneal and cervical ligaments resist?
-all motions
-mostly INVERSION
96
what type of joint is the subtalar joint?
-plane
-1 DOF
-oblique axis or rotation
-curvlinear axis
97
in open chain subtalar eversion and inversion what bones moves on what?
calcaneus on talus
98
in open chain pronation what motions does the calcaneus move in?
-eversion and abduction
-minor dirsiflexion
99
in open chain pronation what motions does the calcaneus move in ?
-inversion and addcution
-minor plantarflexion
100
what is a curvilinear axis?
-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
101
what happens in closed chain pronation at the subtalar joint?
-talus on calcaneus
-talus eversion and abduction and slight dorsiflexion
102
what happens in closed chain supination at the subtalar joint?
-talus on calcaneus and calcaneus on talus for inversion
-talus on calcaneus for adduction and minor plantarflexion
103
what are other names for the transverse tarsal joint?
-choparts joint
-midtarsal joint
104
what are the actions at the transverse tarsal joint?
pronation and supination
105
what type of joint does a talonavicular joint resemble?
ball and socket
106
does the talonavicular joint share a joint capsule?
-yes
-with the anterior subtalar capsule
107
what happens to the talus during weiaght bearing?
-depress and turn medially
108
what does the spring ligament support?
medial longitudinal arch
109
what does the calcaneal cuboid joint resemble?
-saddle joint
-more stable
-less motion
-has its own capsule
110
during pronation and suination what are the two main joints involvoed?
-subtalar
-transverse tarsal
111
how many DOF are at the transverse tarsal joint?
-complicated
-has both a longitudinal and oblique axis
112
what happens during open chain supination at the transverse tarsal joint?
-tibialis posterior spins navicular
-raise medial longitudinal arch
-navicular and cuboid move on talus and calcaneus
113
what happens during open chain pronation at the transverse tarsal joint?
-fibularis longus controls pronation
-navicular and cuboid move on talus and calcaneus
114
what happens during closed chain pronation at the transverse tarsal joint?
-subtalar pronates and GRF causes trasnverse tarsal joint to supinate
115
what happens during clsed chain supination at the trasnverse tarsal joint?
-subtalar supinates and lack of GRF cuases the transverse tarsal joint to pronate
116
what is the distal intertarsal joint?
-cuboid and navicular with cunieforms
-assists with pronation and supination
-stability across transverse arch
117
what is the keystone of the transverse arch?
-intermediate cunieform
118
what is another name for the tarsometatarsal joint?
-lisfranc joint
119
what happens at the tarsometatarsal joint?
-greatest moility at 1st, 4th, 5th joint
-only 1st has a joint capsule
-instability can lead to OA, pes planus, hallux valgus
120
what is the metotarsal phalangeal joint?
-2 DOF (DF, PF, ab/ad)
-2 sesmoid bones in FHB to increase leverage
121
what happens at the IP joints?
-hinge joint
-1 DOF (DF/PF)
-mobility greater proximally than distally
122
how many arches are there in the foot?
3
123
what is the importance of medial longitudinal arch?
-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
what is the keystone of the medial longitudinal arch?
talonavicular joint
125
as the arch depresses what happens to the rearfoot?
-everts slightly
126
what is pes planus?
-low arch
-weak tib posterior tendon, platar fasica, or sping ligament
-rearfoot eversion and depressed talus and navicular
127
what are the two types of pes planus?
-rigid = congenital
-flexible = normal in NWB, flattens during WB
128
what is the windlass effect?
-lengthening plantarfascia increased medial ongitudinal arch height
-if dont see arch raise could be sign of problem with plantar fascia
129
what muscles contribute to dorsiflexion?
-TA
-EHL
-EHB
130
what muscles contribute to plantar flexion?
-TP
-gastroc
-soleus
-FDL
-FHL
131
what muscles contribute to inversion?
-TP
-TA
-FDL
-FHL
-EHL
132
what muscles contribute to eversion?
-fibularis longus and brevis
-EDL
133
what is the most commonly injured lateral ankle ligament?
ATF
134
what test can you use to test for ATF integrity?
anterior drawer
135
what test can you use to test for CF integrity?
talar tilt test
136
what is the most common mechanism for a high ankle sprain?
-forceful external rotation of talus
-mortise comes apart
137
what test can you use to test the integirty of the high ankle/ tibfib ligaments?
syndesmosis squeeze test
138
which femoral condyle is larger?
medial
139
what shape are the medial and lateral condyles of the femur?
convex
140
what is the concavity of the trochlear groove?
-ML concave
-convex AP
141
what is the concavity of the tibial condyles?
-medial concave
-lateral flat/convex
142
which tibial condyle is larger?
medial
143
what is the importance of the intercondylar eminence?
attachment sites for cruciate ligaments
144
what is the concavity of the anterior patella?
convex in all directions
145
what is the concavity of the posterior patella?
-vertical ridge
-medial and lateral facets
-odd facet on medial side
146
what does the femur slant obliquely due to?
angle of inclination
147
what is the normal absolute angle of the knee?
170-175
148
what is normal and abnormal valgum?
-5-10 genu valgum normal
->15 abnormal
149
what is abnormal genu varum?
-any varum
->0 degrees
150
what are knee bursae?
-fluid filled sac that cushions bones, tendons, and muscles around the joint
-~14 in the knee
151
what provides lateral knee stability?
1. LCL
2. IT band
3. lateral patellar retinaculum
152
what provides medial knee stability?
1. MCL
2. medial patellar retinaculum
3. medial joint capsule thickened
153
what provides anterior joint stability of the knee?
1. medial and lateral patellar retinaculum
2. patellar tendon
154
what provides posterior joint stability?
-oblique ligament
-arcuate ligament
155
what is the knee retinaculum?
-bands of fibrous tissue that support the patella
-insert on anteromedial and anterolateral tibia
156
what wears away during knee OA?
-articular cartiledge
157
what are the two types of cartidledge in the knee?
-menisci
-articular cartiledge
158
what are the knee menisci?
-fibrocartilagenous structures
-create seats for convex femur
-outer 1/3 more vascularized and easier to heal
159
. what anchors the menisci?
anterior and posterior horns
-anchor to the bone
160
what are the 4 ligaments that stabilize the menisci?
1. coronary
2. transverse
3. meniscofibular
4. meniscofemoral
161
what are the coronary ligaments?
-external edge of mensici to tibia
-loose
162
what are teh transverse meniscal ligaments?
-stabilize two menisci together
163
what are the meniscofibular ligaments?
-stabilize lateral menisci
164
what are mensicofemoral ligaments?
-stabilize lateral mensici to femur
165
what part of the mcl is attached to the medial meniscus?
-posteriomedial border
166
what is the primary function of the menisci?
-reduce stress across knee by increasing surface area
-triple contact of joint
167
what are the secondary functions of the menisci?
-stabilize joint in motion
-libricate
-proprioception
-guide arthrokinematics
168
what is stress?
force/area
169
how much compressive force acts at the tibia during walking realtive to body weight?
2.5-3x
170
what type of joint is the knee/tibiofemoral?
condyloid
171
how many degrees of freedom does the knee have?
-2 or 3
-flex/ext, IR/ER, valgus/varun
-valgus/varum is passive
172
how does the axis rotate during knee flexion?
-posterior inferior
173
when is the moment arm greatest for knee extensors?
-full extension
174
when is the moment arm greatest for knee flexors?
-mid range
175
at what range do we have the most and least knee IR/ER?
-most during 90 degrees of flexion (40-50)
-least in full extension
176
what is the closed packed position of the knee?
full extension
177
what muscles direct the toll and stabilize the menisci?
quads
178
at what range does the screw home mechanism occur?
last 30 degrees of ROM
179
what is the skrew home mechanism?
-lock knee into full extension
-open chain 10 degree tibia ER
-closed chain 10 degree femur IR
180
what kind of motion is the screw home mechanism considered?
-conjunct
-b/c can not be separated from knee flex/ext
181
what are the three factors driving the skrew home mechanism?
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
how does popliteus unlock the knee>
-femural ER
-tibial IR
183
what is the arthorkinematics of knee IR/ER?
-SPIN
-cuases deformaiton and compression of menisci and femoral condyles
184
what are the layers of the MCL?
-superficial layers connect to medial epicondyle, proximal tibia, and medial retincaulum
-deep fibers connect to medial mensicus and semimembranosus
185
what are the functions of the MCL?
-resist valgus
-stabilize knee in extension
-resist extreme ER
186
what is the importance of the LCL?
-short and vertical
-attaches to head of fibula
-half tensile strength of MCL
-blends with biceps femoris tendon
-no connectionto retinaculum or mensici
187
what is the function of the LCL?
1. resist varus
2. stabilize in extension
3. resist extreme IR and ER
188
what is the attachment point of the ACL?
-medial portion of lateral condyle of femur
189
how many bundles does the ACL have?
-2 collagen twist fibers
-anterior and posterior
190
what is the primary function of the ACL?
-prevent anterior translation of tibia
191
where is the ACL most taut?
full extension
192
how does the ACL help with open chain extension?
-prevents excessive anterior slide
193
what is an antagonist to the ACL?
-quads
-quads in extension side tibia anteriorly which stresses the ACL
194
what is the attachment of the PCL?
-lateral aspect of the medial femoral condyle
195
how many bundles does the PCL have?
-2 collagen twists
-anterior and posterior
196
what is the primary function of the PCL?
-posterior translation of tibia
197
where is PCL most taut?
-flexion
-90-120 degrees
198
how does PCL help with flexion in open chain?
-prevent excessive posterior slide of tibia
199
what is a PCL antagonist?
-hamstrings
-increasing flexion put more strains on PCL
200
what is the MOI for MCL?
valgus
201
what is the MOI for LCL?
varus
202
what is the best knee angle for MCL and LCL stress tests?
-30 degrees
203
what are the MOIs for the ACL?
-strong quad contrationw ith no flexion
-anterior tibial translation
-valgus collapse of the knee
-excessive rotation (especailly IR)
-hyperextension of knee
204
what is protective to the ACL?
-hamstring activation decresses ACL stress
-especially at higher knee flexion
205
how does valgus/varus stress affect ACL injury?
-ACL strain does not increase with greater valgus/varus
-in NWB no ACL strain with valgus and varus
206
is there more ACL strain with IR or ER?
-2x more with IR
-bigger difference with WB
207
what knee angle is the anterior drawer test at?
90 degrees
208
what knee angle is the lachmans test?
30 dgerees
209
what is the MOI of the PCL?
-trauma (usually occur with other structures)
-falling on flexed knee
-dashboard injury
210
what is the clinical test for PCL?
-posterior drawer
-at 90 dgerres PCL provides 95% positioier translation support
211
where is the greatest stress on the meniscus?
-posterior horns
212
what is hoop stress?
-force dispersed along meniscal curvaturef
213
what does damage to the meniscus especially the posterior horn cuase?
-decrease ability to withstand hoop stress
-less area avilable to disperse force
214
what percentage of ACL involove mensical injury?
50%
215
what is the MOI of meniscal injury?
-forceful axial rotation in WB
-axial torsion pinches and dislodges menisci
216
what meniscus is more commonly injured?
-medial
217
what are the muscles that flex the knee?
-hamstrings, sartorius, garcilis, popliteus, gastroc, plantaris
218
what muscles extend the knee?
quads
219
what muscles IR the knee?
popliteus, semimem, semit, sartorious, gracilis
220
what muscles ER the knee?
biceps femoris
221
for the knee extensors what is the greatest leverage point vs greatest torgue production?
-torque generally coincides with maximal leverage
-more torque in slightly more flexion
222
what knee extensor has the larget PCSA?
vastus lateralis
223
how much force can the quads produce?
6-9x BW
224
what way do the quads bias line of pull?
-laterally 7-10 degrees
225
what is the Q angle?
angle b/w line of pull of quads and patellar tendon
-13-15
226
for the knee flexors where is the most leverage and most torque produced?
-most leverage a mid range
-most torque produced at extension b/c optimal cross bridges
227
how does the soleus affect the knee?
-in closed chain pulls tibia posterior
-can protect ACL
-assists hamstrings in protecting ACL
228
how does glut max affect the knee?
-in closed chain posteriorly
-thus anterior distplacment of tibia and stress on ACL
229
what motions can the patella have?
-medial/lateral shift
-medial/lateral rotation
-medial and lateral shift
230
during knee flexion how does the patella move?
moves inferioly
231
during knee extension how does the patella move?
moves superioly
232
in open chain knee motion what is the patellar arthrokinematics?
-tibia on femur
-patella slides on fixed femur
233
in closed chain what is the patellar arthrokinematics?
-femur on tibia
-femur slides realtive to fixed patella
234
what is the path of patellar contact with femur?
-flexion: superior pole mostly contacted
-mid range 90-60 greatest area of contact
-extension; inferior pole most contact
235
at most contact how much of patella is in contact with femur?
-1/3
236
what is the purpose of patella?
-more levaerage b/c increased MA
237
what are the two reasons for poor PF joint tracking?
1. malalignment
2. maltracking
238
is there more or less stress when patella is maltracking?
-more stress b/c decreased SA
239
what can cause lateral tracking of patella?
-quads
-lateral retinaculum
-IT band b/c connected to lateral retinaculum
240
what can cause medial patellar tracking?
-quads (VMO)
-medial retinacular fibers
-lateral facet of patella is steep and blocks lateral shift
241
can therapist target WMO?
NO
242
how does medial collapse effect PF tracking?
-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
what does the sacrospinous ligament form?
greater sciatic foramen
244
what does the sacrotuberous ligament form?
lesser sciatic foramen
245
what attaches at the ischial tuberosity?
--hamstrings
-adductor magnus
-sacrotuberous ligament
246
what is the pubic symphasis?
-synasrthrosis: hyalin cartiledge
-resist shear stress
-collagen type I
-allows up to 2mm translation and slight rotation
247
what bone makes up most of the acetabulum?
-ischium
248
what bones makes up the least amount of the acetabulum?
-punic
249
is the acetabular rim a complete circle?
no
-opening 60-70 degrees
-helps ROM but decreases stability
250
what is the lunate surface of the acetabulum?
-where femoral head contacts the acetablum
-thickest superior and anterior
-covered with articular cartiledge
-aera with hight joint contact forces
-3x body weight
251
what way does the femoral head project?
-medial, superior, anterior
252
what way does the femoral shaft project?
-slight anterior convexity
-allows for bowing in WB
253
where do the distal capsular ligaments of the hip attach?
-intertrochanteric line
254
does the fovea have cartiledge?
-no
-no femoral head contact
255
what is the angle of inclination?
-femoral neck and femoral shaft
-normal 125 degrees
256
what is coxa vara?
-angle of inclination < 110
-congenital or injury caused
-can cause limb to be shorter
257
what is coxa vlaga?
->135 angle of inclination
-often present with CP
-can cause limb to be longer
258
does coxa valga or coxa vara have to produce more force for abduction?
-coxa valga
-less moment arm
259
what is femoral torsion angle?
-in trasnverse plane
-angle b/w ML axis and femoral neck
-8-20 normal
260
what os femoral anteversion?
->20
-causes in toeing
-b/w femur roates ER so tibia rotates IR to maintain congruency
261
what is femoral retroversion?
-<8
-causes out toeing
-b/c femur rotates IR so tibia rotates Er to maintain congruency
262
are we born with voxa valga and high angles of inclination?
-yes
-decreses with WB in development
263
what is the importance of the ligamentum teres?
-in newborns provides stability and blood supply
-in adults unknown may aid in propriocenption
264
where is ligamentum teres taut?
-flexion
-adduction
-IR
265
what is the importance of the acetablular labrum?
-apex projects outward
-bends with articular cartiledge
-grips and provides suction seal for femur
-limited vascular supply
266
what is the center edge angle?
-from vertical line and superior endge of acetabulum
-20-25 average
267
what can low center edge angle cause?
-less contact aera
-greater joint stress
-higher superior dislocation risk
268
what can high center edge angles cuase?
-increase chnace of impingement
269
what is the acetabular anteversion angle?
-degree to which acetablum faces anteior
-20 normal
270
what can high angles of anterversion cause>
-general instability
-higher risk for subluxation
271
what does the transverse acetabular ligament connect?
-acetabular notch
272
what is the importance of the hip joint capsule?
-very strong
-makes joint stable
-thicker anterior superior to assist in WB
-resistance fo end range flexion and extension
273
what is the importance of the iliofemoral ligaments?
-resist extension, ER and slight abduction
-stringest lig
-resist hip extension in standing
274
what is the importance of the pubofemoral ligament?
-maily resists abduction
-also resists extension and slight external rotation
-distal end fuses with Y ligament
275
what is the importance of the ischiofemoral ligament?
-twisted fibers
-some IR resistance
-some extension and adduction resistance
-weakest of hip ligaments
276
what is the closed packed position of the hip?
-extension, abd, IR
-where all hip ligaments are streched to increase stability
277
what is the point where the hip has the most ocngruency?
-90 flex, abd, Er
278
what is the arthrokinmeatics for open and closed chain hip flexion and extension
spin
279
what are the arthrokinematics from hip open chian abduction?
-roll superior
-slide inferior
280
what are the arthrokinemaitcs for hip open chain adduction?
-roll inferior
-slide superior
281
what are the arthrokinematics for hip closed chain elecation/abduction?
-roll superior
-slide superior
282
what are the arthrokinematics for hip closed chain drop/adduction?
-roll inferior
-slide inferior
283
what are teh srthokinematics for hip open chain IR?
-roll anteiror
-slide posteiror
284
what are the arthrokinematics for hip open chain ER?
-roll posterior
-slide antieor
285
what are the hip arthrokinematics for hip closed chain IR?
-roll anteiror
-slide anterior
286
what are the hip arthrokinematics for hip closed chain ER?
-roll posteior
-slide posterior
287
what is the most prominent hip flexor in open chain?
-iliopsoas
288
how does the iliopsaoas MA chnage with flexion and why?
-increase toward 90
-helps compensate for muscle length tension relatioship not being optimal
289
why are abdominal muscles important to hip flexion?
-helps fix pelvis in posterior tilt so we can get stronger hip flexion
290
what part of adductor magnus has good hip extension function?
-posterior
291
is hip extensor torque greater with knee flexion or extension?
-extension b/c hamstrings not shortened so they have more passive tension in extension
292
does hamstring moment arm increase or decrease with trunk flexion?
-increase
293
does glut max moment arm increase or decrease with trunk flexion?
-decrease
294
what is the JRF on teh hip during standing?
2.5x BW
295
what angle is hip abductor torque the greatest?
10 degrees adduction
=where we are strongest in stance phase
296
during running what is the advantage of earlier muscle activation?
-less hip adduction motion which is good
-less vlagus
297
in what hip position is adductor magnus posterior fibers a good extender?
any position
298
in what angle are teh other adductors of the hip good hio flexors?
0-40
299
in what angle are the other adductors of the hip good extendors?
70-100
300
where is glut med and min a stronger IR?
in 90 degrees of hip flexion
301
where are glut max and piriformis good IR?
90 degrees of hip flexion
302
where is obturator internus a good IR?
-never
-always an ER but worse moment arm in flexion
303
where happens to obturator externus and quadratus femoris at 90 degrees of hip flexion?
-better ER
304
how does hip ER torque change with hip flexion?
-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
do we have more hip rotation in prone or seated?
-prone
-seated limitation from capsule
