foot biomechanics inc gait cycle Flashcards
1
Q
What does the subtalar joint consist of and what is its motion?
A
- Calcaneus
- Talus
Motion
- Inversion/eversion
- No role in plantar flexion/dorsoflexion
2
Q
What does the midfoot consist of and what is its motion?
A
- Intercuneiform
- naviculocuneiform joint
- Tarsalmetarsal joint ( lisfranc)
- divided into 3 colums
- Medial
- First MT
- Medial Cuneiform
- Navicular
- Middle Column
- 2/3 MT
- middle cuneiform
- Lateral cuneiform
- Lateral
- 4/5Th MT
- Cuboid
- Medial
Motion
- Lateral column is the most mobile
- allows for flexibility whne walking on uneven ground
- Middle Column is the least mobile
- Allows for rigidity during push -off
- Medial column carried most of load when standing
3
Q
What does chopart joint consist of and what is tis motion?
A
- Talonavicular
- Calcaneocuboid
Motion
-
Inversion of subtalar joint locks the Transverse Tarsal joint
- allows for stable hindfoot/midfoot for toe off
-
Eversion of subtalar joint unlocks the transverse tarsal joint
- allows for supple foot to accomodate ground just after heel strike
- Plantar aponeurosis is primary structure of load/force transfer between hindfoot and forefoot during stance
4
Q
What does the forefoot consist of?
A
- Metarsal phalangeal joints
- proximal phalangeal joints
- distal interphalangeal joints
- 2nd MT experiences more stress during gait
- most common MT to have STRESS FRACTURE
5
Q
What does one gait cycle measure?
A
- From heel strike to heel strike
6
Q
Define a stride ?
A
- One full gait cycle
- From heel- strike to heel- strike
7
Q
What is a stride made up of ?
A
- A Stance phase
- A swing phase
8
Q
What is the stance phase? How much of the gait cycle does it occupy?
A
- Period of time the foot is ON the ground
- 60% of one gait cycle is spent in stance
- Heel strike to toe off
9
Q
What is the swing phase?
A
- The period of time the foot is OFF the ground moving forward
- Toe off to heel strike
- 40% one gait cyle is spent in swing
10
Q
What is walking?
A
- A period of double limb support in addition to always having one foot in contact with the ground throughout the gait cycle
11
Q
What is ground reaction force during walking and running ?
A
- 1.5 walking
- 3-4 times in running
12
Q
What is the centre of gravity of the body?
A
- 5cm anterior to S2 Vertebral body
- displaced 5cm vertically and horizontally during adult male step
13
Q
Describe the phases of the stance phase of the gait cycle and muscle involvement?
A
‘I like my tea presweetened’
-
Inital contact= HEEL STRIKE
- when foot contact ground
- tibialis anterior- eccentric contraction - lengthens- controls rate of decent of foot- loss = slap foot. Hip extensors contract, quads contract eccentrically
- Hindfoot - everted, unlocked- absorb ground- Transverse tarsal axes are parallel & flexible
-
Loading responde ( double limb support)
- Occurs after inital contact until elevation of opposite limb
- ankle dorsiflexors - tibialis anterior contract eccentrically to control planar flexion
- Quads contract to stabilise knee and counteract flexion moment
- Mid Stance
- From elevation of opposite limb until both ankles are aligned in coronal plane
- Hip extensors and quads undergo concentric contraction- controls progeession of body over foot- effected in quads weakness -pt leans forwarad to put centre og gravity anterior of knee-> knee hyperextension
-
Terminal Stance ( single leg stance)
- from ankle are aligned to until opposite to when heel strikes in controlateral limb
- Toe flexors contribute
- gastron/ soleus complex- concentric ( shortening)
-
Pre- swing ( second double limb stance)
- from initial contact of opposite limb to just prior to elevation of ipislateral limb
- HIp flexors contract to propel limb
14
Q
What is the windlass mechanism ? When does it occur ? What else occurs during this time?
A
- Plantar fascia attached to medial plantar plane to pipj ( past mtpj)
- Pt tightens as mtp extend and toes dosiflex. This pulls tarsal bones together locking them in place. Occurs in stance phase from heel strike to toe off.
- Post tibialis fires and supinates the hind foot-> the transverse tarsal joint/ chopart locks and provides a rigid lever ready for toe off
15
Q
What happens in foot drop?
A
- Loss of anterior tibialis due to peroneal neve palsy
- heel strike- foot cannot be lowered controlled so ‘slaps ground- no eccentric contraction of tibilalis anterior
- during swing phase- weakness in tibialis anterior -> steppage gait as hip flexors and knee flexors have to increase to clear foot from ground
17
Q
Describe the stages of the swing phase of gait cycle?
A
- ‘In My Teapot’
- quads silent in swing phase
-
Inital contact-Toe off
- from elevation of limb to point of max knee flexion
- hip flexors contract
- Inversion of calcaneus locks transverse tarsal joints
- weakness of hamstrong/hip flexors affect swing phase- limit limb advancement
-
Mid swing ( foot clearance)
- Following knee flexion to point where tibia is vertical
- ankle dorsiflexion contract to ensure foot clearance
-
Terminal swing
- from point where tibia is vertical to just prior to inital contact
- hamstring muscles decelerate forward of thigh
20
Q
Decribe the anatomy of tibialis abterior?
A
- origin- Gerdy’s tubercle, lateral condyle of tibia
- insertion 1st cuneiform and base of 1st MT
- innervation= deep peroneal nerve
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