Ankle and Foot Biomechanics Flashcards
(230 cards)
1
Q
What is pronounced interdependence
A
If you have pathology of the foot/ankle it can cause pathology further up the chain or vice versa
2
Q
How many bones are in the ankle/foot
A
28
3
Q
How many joints are in the ankle.foot
A
25
4
Q
True or False:
The ankle/foot is capable of producing a large amount of force but also can be very delicate
A
True
5
Q
Does the ankle/foot have mobility and stability or both
A
Both
6
Q
What are the functions of the foot/ankle for stability (2)
A
- Act as a rigid lever
2. Provide stable BOS
7
Q
What are the functions of the foot/ankle for mobility (3)
A
- Flexible to absorb shock
- Adapt to varied surfaces
- Dampen LE rotations
8
Q
True or False:
Repetitive shear forces are not detrimental to humans
A
False
9
Q
What comprises the forefoot (2)
A
- Metatarsals
2. Phalanges
10
Q
What comprises the midfoot (3)
A
- Navicular
- Cuboid
- Cuneiforms (3x)
11
Q
What comprise the hindfoot (2)
A
- Talus
2. Calcaneus
12
Q
What is a ray
A
The metatarsal and corresponding cuneiform or cuboid
13
Q
What does the hindfoot do
A
Converts LE transverse plane motion into sagittal, frontal, and horizontal plane motion
14
Q
What does the midfoot do (2)
A
- Transmits hindfoot motion to the forefoot
2. Promotes stability of foot
15
Q
What does the forefoot do
A
Adapts to the terrain
16
Q
True or False:
The hindfoot is the king/queen and the midfoot and forefoot are subservient to the hindfoot
A
True
17
Q
What motion would occur in the sagittal plane at the foot/ankle
A
Plantarflexion and dorsiflexion
18
Q
What motion would occur in the transverse plane at the foot/ankle
A
ABD/ER/LR and ADD/IR/MR
19
Q
What motion would occur in the frontal plane at the foot/ankle
A
Inversion/Varus and Eversion/Valgus
20
Q
What is inversion
A
Plantar surface faces inward
21
Q
What is eversion
A
Plantar surface faces outward
22
Q
What is valgus
A
The distal segment points away from the midline
23
Q
What is varus
A
The distal segment points towards the midline
24
Q
What motions does the foot and ankle move
A
Pronation and supination
25
What motions accompany pronation of the foot/ankle
Dorsiflexion, eversion/valgus, and ABD/ER/LR
26
What motions accompany supination of the foot/ankle
Plantarflexion, inversion/varus, and ADD,IR,MR
27
True or False:
| The foot/ankle is a single axis triplanar motion joint
True
28
How can one axis have 3 planar motions
The axis crosses all of the planes
29
What makes up the talocrural joint (3)
1. Tibia
2. Fibula
3. Talus
30
What makes up the proximal talocrural joint (2)
1. Tibia
| 2. Fibula
31
What makes up the distal talocrural joint
Talus
32
What is the mortise
The distal tibia and fibula
33
Describe the structure of the proximal talocrural joint (2)
1. Concave
| 2. Lateral to medial asymmetry
34
What is an ankle fracture
Fracture of the fibula
35
What is the most commonly sprained ligament
Anterior talofibular ligament (ATFL)
36
Which malleolus is more anterior and which is most posterior
Anterior: Tibia
Posterior: Fibula
37
Where is there more concavity in the proximal talocrual joint
Anteriorly
38
Where is the talus wider anterior or posterior
Anterior
39
how much wider can the anterior of the talus be compared to the posterior
Up to 25%
40
What is the closed pack position of the talocrural joint
Dorsiflexion
41
True or False:
| The distal talocrural joint is shaped like a truncated cone with the apex directed medially
True
42
Which talar surface area is greater medial or lateral
Lateral
43
What articulates with the medial side of the talus
Tibial malleolus
44
What articulates with the lateral side of the talus
Fibular malleolus
45
What occurs at the fibula and tibia to allow for full motion to occur
Rotation
46
What shape does the talar surface have
Convex
47
What is another name for the medial ligament of the talocrural joint
Deltoid ligament
48
What ligaments makes up the deltoid ligament (3)
1. Calcaneotibial ligament
2. Anterior talotibia ligament
3. Tibionavicular ligament
49
What is the deltoid ligament a check reign to
Eversion
50
True or False:
| You are more likely to avulse the tibial malleolus instead of spraining the deltoid ligament
True
51
What is the anterior talofibular ligament a check reign to
PF and inversion
52
What is the calcaneofibular ligament a check reign to
PF and inversion
53
What ligament is most commonly sprained because of pure inversion
Calcaneofibular ligament
54
Where are the posterior talofibular and posterior talotibial ligaments in relation to the axis of rotation
Posterior to the axis of rotation
55
What are the posterior talofibular and posterior talotibial ligaments check reigns to
Dorsiflexion
56
What is the plantar calcaneonavicular ligament also called
Spring ligament
57
What is the function of the calcaneonavicular ligament
Be a shock absorber to control and stabilize the medial longitudinal arch
58
How much dorsiflexion occurs at the talocrural joint OKC
20-35
59
How much plantarflexion occurs at the talocrural joint OKC
30-50
60
How much adduction occurs at the talocrural joint OKC
7
61
How much abduction occurs at the talocrural joint OKC
10
62
How much inversion occurs at the talocrural joint OKC
5
63
How much eversion occurs at the talorcrual joint OKC
5
64
Why does the most motion occur in PF/DF at the talocrural joint
The axis of rotation is closest to the M-L axis
65
How much PF/DF is needed during gait at the talocrural joint
DF: 10
PF: 20
66
How much PF/DF is needed while ascending stairs at the talocrural joint
DF: 20-25
PF: 10-15
67
How much PF?DF is needed while running at the talocrural joint
DF: 25
PF: 25
68
What is the compression force at the talocrural joint during the gait cycle
4.5 times the body weight
69
How far is the axis of rotation from the M-L axis
8-10
70
How far is the axis of rotation from the longitudinal axis
80
71
How far is the axis of rotation from the A-P axis
60-70
72
Where is the talar surface area greater lateral or media
Lateral
73
Where does greater slide occur the lateral or medial side and why
Lateral do to the greater surface area
74
What does greater glide on the lateral side result in during OKC DF at talocrural joint
Abduction of the talus in the mortise
75
What does greater glide on the lateral side result in during CKC DF at talocrural joint
IR/ADD of the mortise on the talus
76
What does medial rotation of the mortise on the talus equal
Medial rotation of the lower leg on the talus
77
Where is the radius of curvature of the talus greatest lateral or medial
Lateral
78
What happens to the fibula during CKC talocrural DF due to the greater lateral curvature
Medial fibular rotation
79
What happens to the fibula during CKC talocrural PF due to the greater lateral curvature
Lateral fibular rotation
80
Does the proximal tib fib have any bearing on the knee
No but extremely important for ankle movement
81
How much superior glide does the tib fib joint have
3-5mm
82
How much of the body weight does the fibula bear
10%
83
When does the fibula glide superiorly
During dorsiflexion when larger portion of the talus enters the mortise
84
What are the muscular check reins to DF
Soleus and gastrocnemius
85
What are the muscular check reins to PF
Tibialis anterior, extensor hallucis longus, extensor digitorum longus
86
What are the muscular check reins to eversion stress
Tibialis posterior, flexor digitorum longus, flexor hallucis longus
87
What are the muscular check reins to inversion stress
Fibularis longus and brevis
88
True or False:
| The subtalar joint can do a lot of excessive pronation and supination
True
89
How are the facets oriented on the calcaneus
Anterior: Concave
Middle: Concave
Posterior: Convex
90
How are the facets oriented on the talus
Anterior: Convex
Middle: Convex
Posterior: Concave
91
How are the 3 articulations of the subtalar joint separated
Tarsal canal
92
What are the main functions of the subtalar joint (2)
1. Dampen LE rotary forces
| 2. Maintains foot contact with ground
93
Which articulations of the subtalar joint are separated by the tarsal canal
Anterior and middle from the posterior
94
What is the sinus tarsi
Bullet hole between the talus and calcaneus
95
Which side is the sinus tarsi on
The lateral side of the foot
96
Where does the tarsal canal run
Opens laterally anterior to the fibular malleolus and terminates posteromedially directly behind the susentaculum tali
97
What side of the talus is the interosseous talocalcaneal ligament and what motion does it limit
Medial side and it limits eversion
98
What motion does the lateral talocalcaneal ligament limit
Inversion
99
What side of the talus is the ligamentum cervicis and what motion does it limit
Lateral side and it limits inversion
100
What side of the talus is the posterior calcaneal ligament and what motion does it limit
Posterolateral and it limits inversion and dorsiflexion
101
During OKC what occurs at the subtalar joint during supination
Calcaneal inversion, adduction, and plantarflexion
102
During OKC what occurs at the subtalar joint during pronation
Calcaneal eversion, abduction, and dorsiflexion
103
Inversion can also be called what
Varus
104
Eversion can also be called what
Valgus
105
Body weight (BW) prevents the calcaneus from doing what 2 motions
ABD/ADD or PF/DF
106
During CKC what occurs at the subtalar joint during supination
Calcaneal inversion, talar abduction, and dorsiflexion
107
During CKC what occurs at the subtalar joint during pronation
Calcaneal eversion, talar adduction, and plantarflexion
108
What is the closed pack position of the subtalar joint
Supination
109
How much inversion and eversion are available at the subtalar joint
Inversion: 20
Eversion: 10
110
Where does the extra 3 degrees of ADD come from for the remainder of gait
Another joint higher up
111
During CKC what are the arthrokinematics of the talus on the calcaneus (all 3 surfaces)
Anterior and middle: Convex talus on concave calcaneus
| Posterior: Concave talus on convex calcaneus
112
True or False:
You aren't able to stabilize the posterior facet and move the anterior and middle facets of the talus because the motions occur simultaneously
True
113
What type of motion is the talus on calcaneus
A complex screw like motion
114
True or False:
The axises cross during supination of the foot at the subtalar joint providing the greatest stability (closed pack position)
True
115
What is the AOR angles of inclination for the subtalar joint
42 degrees from ground and 16 degrees from midline
116
What motions at the subtalar joint are about equal because of the angle of inclination of the AOR
IN/EV and ABD/ADD
117
What is the ratio of ROM at the subtalar joint of the 3 planes of motion
4:4:1
| 1 being DF/PF
118
What is subtalar neutral
The position where the joint is in its optimal developmental position
119
What is normal inversion and eversion of the subtalar joint
Inversion: 20
Eversion: 10
120
What is the proportion of inversion to eversion at the subtalar joint
Inversion: 2/3
Eversion: 1/3
121
How do you determine a person's subtalar neutral
Add together the inversion and eversion then divide by 3 and subtract that number from the eversion
122
If the number you get is positive what does that mean
The patient's subtalar neutral is that many degrees of valgus
123
If the number you get is negative what does that mean
The patient's subtalar neutral is that many degrees of varus
124
What does a negative number mean for subtalar neutral in terms of midline
It means that you have crossed midline into varus
125
What is the subtalar neutral position
The point from which the calcaneus can invert twice as much as it can evert
126
Will severe restriction of talar abduction PROM lead to reduction in supination or pronation ROM in an open or closed kinematic chain or both
Supination in CKC because the talus is moving on the calcaneus in CKC and when doing CKC supination the talus moves into dorsiflexion and abduction which wouldnt be able to occur
127
What motion occurs at the LE when you attempt to forcibly pronate both feet with the knees extended
Medial rotation of the LE occurs via mortis congruity
128
The subtalar joint is like what type of hinge
A mitered hinge
129
What does the subtalar joint being like a mitered hinge do during medial rotation of the leg
Pronation occurs at the foot
130
What does the subtalar joint being like a mitered hinge do during lateral rotation of the leg
Supination of the foot occurs just not as much becauses bone approximate and the axises cross resulting in the closed pack position of the foot
131
What is the keystone of the medial longitudinal arch of the foot
Navicular
132
What 2 joints make up the talocalcanealnavicular joint (TCN)
1. Talonavicular
| 2. Subtalar
133
What is the shape of the talonavicular joint
Convex talar head and concave posterior navicular
134
The talonavicular is also part of what other joint
Transverse tarsal joint
135
What type of joint is the talonavicular joint
Ball and socket like
136
What do ligaments do to the navicular concavity
Deepen it
137
What sets off pronation during the gait cycle
Initial contact
138
When should pronation end during the gait cycle
At midstance
139
What ligament is responsible for holding up the navicular
Spring ligament
140
What is the talocalcanealnavicular joint axis
40 off the ground and 30 from midline
141
Which joint has more DF/PF subtalar or TCN
TCN
142
Which joint has more ADD/ABD and IV/EV subtalar or TCN
They are about the same
143
What comprises the transverse tarsal joint (2)
1. Talonavicular joint
| 2. Calcaneocuboid joint
144
True or False:
| The transverse tarsal joint divides the hindfoot from the mid foot
True
145
What type of surfaces do the anterior calcaneus and posterior cuboid have
Sellar or saddle joint
146
How many joints does the talonavicular joint belong to
2
147
What are the ligaments of the transverse tarsal joint calcaneocuboid articulation (4)
1. Lateral band of the bifurcate ligament
2. Dorsal calcaneocuboid ligament
3. Short plantar ligament
4. Long plantar ligament
148
What do the short and long plantar ligaments form
Plantar calcaneocuboid ligament
149
What does the long plantar ligament do
Aids in maintaining the longitudinal arch of the foot
150
What is the longitudinal axis of the transverse tarsal joint
15 from ground and 9 from midline
151
What motion is the longitudinal axis of the transverse tarsal joint best served for
IV/EV
152
What is the oblique axis of rotation of the transverse tarsal joint
52 from ground and 57 from midline
153
True or False:
| The longitudinal and oblique axes of the TTJ are difficult to separate and quantify
True
154
How much pronation and supination does the TTJ provide compared to the subtalar joint
1/3-1/2
155
True or False:
| STJ and TTJ are linked mechanicaly
True
156
What CKC motions at the STJ (talar) cause motion at the talonavicular joint
ABD/ADD and DF/PF
157
What CKC motions at the STJ (calcaneal) cause motion at the calcaneocuboid joint joint
IV/EV
158
STJ supination equals what at the TTJ
Supination
159
STJ pronation equals what at the TTJ
Pronation
160
What are the two functions of the TTJ
1. Add to supination/pronation of the STJ
| 2. Compensate the forefoot for hindfoot position (keep forefoot on the ground)
161
During medial rotation of the leg how does the STJ and TTJ accommodate to keep the forefoot on the ground (3)
1. Ideally STJ pronation
2. STJ excessive pronation and TTJ pronation
3. Excessive STJ pronation and TTJ supination
162
During lateral rotation of the leg how does the STJ and TTJ accommodate to keep the forefoot on the ground (3)
1. Ideally STJ supination
2. STJ a bit excessive supination TTJ supination
3. STJ excessive supination TTJ supination
163
How can the TTJ supinate while the STJ pronates if the are linked mechanically
Pronation is the loose pack position of the foot
164
Why doesn't the TTJ pronate during excessive STJ supination
Supination is the closed pack position of the foot which is caused by the joint axises crossing
165
What is the main function of the TMTJ
Attempts to maintain forefoot contact with supporting surface especially when TT motion is inadequate
166
Is the motion at the TMTJ considered supination/pronation
Nope
167
What is the motion at the TMTJ considered
Supination twist and pronation twist
168
Why is motion and the TMTJ considered supination twist and pronation twist
There is limited/no ABD/ADD
169
What are the coupled motions of the 1st and 2nd rays (2)
1. Inversion with DF
| 2. Eversion with PF
170
Does the 3rd ray obey the rules of the TMTJ
No because it is purely a DF/PF stable segment
171
What are the coupled motions of the 4th and 5th rays (2)
1. Eversion with DF
| 2. Inversion with PF
172
What happens it the TTJ supination isn't enough to compensate hindfoot pronation
1st and 2nd ray inversion and DF and 4th and 5th ray inversion and PF inverting the entire forefoot
173
What is inversion of the entire forefoot called
Supination twist
174
What is eversion of the entire forefoot called
Pronation twist
175
What occurs with extreme STJ pronation (2)
1. TTJ PF (pronation)
| 2. 1st and 2nd ray DF and IV and 4th and 5th ray PF and IV (supination twist)
176
What occurs with extreme STJ supination (2)
1. TTJ DF (supination)
| 2. 1st and 2nd ray PF and EV and 4th and 5th ray DF and EV
177
When does supination/pronation twist occur
When TTJ motion in unable to compensate for the deformity
178
True or False:
| The plantar arches of the foot are considered structural vaults
True
179
When do the plantar arches start form
At 5 y/o
180
True or False:
| The plantar arch is considered a twisted osteoligamentous plate
True
181
How is the anterior margin (forefoot) of the plantar arch oriented
Horizontal
182
How is the posterior margin (hindfoot) of the plantar arch oriented
Vertical
183
What does the twisted osteoligamentous design allow for
Absorption and distribution of body weight
184
Does the plantar arch flatten or increase with WB
Flattens
185
True or False:
| The osteoligamentous twist imposes both a longitudinal and transverse arch on the foot
True
186
Does the transverse arch increase or decrease in curvature from TMT to MTP
Decreases
187
Where does the longitudinal arch run from
Calcaneus to metatarsal heads
188
Which side do you use as a reference point for the longitudinal arch
Medial side
189
What is the longitudinal arch stabilized by (4)
1. Spring ligament
2. Short plantar ligament
3. Long plantar ligament
4. Plantar aponeurosis
190
Where does the plantar aponeurosis runs
From medial tubercle calcaneus to plantar aspect of MTP heads
191
How does the plantar aponeurosis stabilize the longitudinal arch
Like a tie rod would
192
What form the struts of the foot (2)
Anterior strut: Tarsals and metatarsals
| Posterior strut: Talus and calcaneus
193
What are the struts of the foot subject to
Compression load
194
What is the tie rod subject to
Tension load
195
Where do the plantar pads move during to DF
Distally
196
What happens to the plantar fascia during toe DF
IT is pulled forward and moves around the windlass of the MT heads
197
What does the plantar fascia being pulled forward result in
Supination of the foot which reduces the distance between MT heads and calcaneus
198
How does supination effect the arch of the foot
Increases the arch height
199
How can supination lead to plantar fasciitis
High arch slackens the plantar aponeurosis leading to adaptive shortening and the great toe extension puts extra tension of plantar aponeurosis
200
How can pronation lead to plantar fasciitis
Decreased arch height tension loads plantar aponeurosis and great toe extension further increases that tension
201
What is normal foot alignment
Perpendicular relationship between MT heads and calcaneal bisector
202
How much of the body weight does the talus bear
50%
203
How much of the weight born by the talus goes through the TTJ (forefoot)
50% of weight through talus so 25% of BW
204
How much of the weight born by the talus goes through the STJ
50% of weight through talus so 25% of BW
205
Where should the reaction force be at heel strike
Just lateral to calcaneal centerline
206
How does the center of load pass through the foot
Forward at first and slightly lateral
207
What happens to the forward progression from 30-50% of the cycle
It begins to slow
208
Where does the force shift to conclude stance
Medially to the 1st MT head
209
What 2 muscles stabilize the 1st ray
1. Tibialis posterior
| 2. Fibularis longus
210
What does the tibialis posterior do to the 1st ray (2)
1. PF and ABD 1st digit
| 2. Stabilization at pushoff
211
What are the distal biomechanical consequences of compensatory pronation effecting the tibialis posterior (3)
1. Adduction and plantarflexion of the talus
2. Navicular and medial cuneiform depression
3. Tension overload to tibialis posterior
212
What does the fibularis longus do to the 1st ray (2)
1. PF and ADD 1st digit
| 2. Stabilization at pushoff
213
True or False:
| The fibularis longus tendon is highly influenced by the position of the cuboid pulley
True
214
What does the cuboid pulley do to the fibularis longus
Displaces the fibularis longus tendon inferiorly to improve PF moment
215
What are the distal biomechanical consequences of compensatory pronation effecting the fibularis longus (4)
1. Alteration of the cuboid pulley
2. Reduced fibularis longus advantage to PF and ABD 1st ray
3. Dorsiflexed 1st ray
4. 2nd metatarsal head overload
216
What motion occurs if you are anterior to the TC axis
DF
217
What motion occurs if you are posterior to the TC axis
PF
218
What motion occurs if you are medial to the ST axis
Supination
219
What motion occurs if you are lateral to the ST axis
Pronation
220
What are the 3 ways abnormal foot mechanics manifest
1. Abnormal magnitude of joint motion
2. Excessive speed of joint motion
3. Abnormal temporal sequence of joint motion
221
How is the calcaneus oriented with a rearfoot varus
Inverted
222
What are the consequences that occur if the rearfoot varus is uncompensated for (4)
1. Medial plantar condyle will be off the ground
2. Excessive weight bearing on the lateral foot
3. 5th metatarsal head callus
4. Failure of STJ to pronate reduces shock absoibing qualities of foot
223
What does a compensated rearfoot varus look like
Calcaneal eversion and STJ pronation
224
What are the consequences of an uncompensated forefoot varus (3)
1. Medial foot will be off the ground
2. Excessive WB on 5th ray
3. 5th metatarsal head callus
225
What does a compensated forefoot varus look like
Medial metatarsal depression from STJ pronation
226
What does a rigid forefoot valgus look like
Everted position of the forefoot
227
What are the consequences of an uncompensated rigid forefoot valgus (3)
1. Lateral forefoot will be off the ground
2. Excessive WB on 1st ray
3. 1st metatarsal head callus
228
What does a compensated rigid forefoot valgus look like
Lateral metatarsal heads to the floor by STJ supination
229
What can compensation of a rigid forefoot valgus put the patient at a higher risk for
Inversion sprain
230
What is the order of the joints that will accommodate for a foot deformity (3)
1. Subtalar joint
2. Transverse tarsal joint
3. Transverse metatarsal joint
