Gait and posture Flashcards
What sort of features of normal gait vary from person to person?
Stride length
Pelvic movement
Upper body position
What does normal gait rely on?
Joints
- intact and functioning
Muscles
- adequate strength
Nerves
- CNS & PNS
Vision
- information about movement of head and body relative to surroundings
- important for the automatic balance responses to changes in surface conditions
- vestibular and auditory systems
Why are gait changes seen in the elderly?
Reduction in muscle bulk
Reduction in strength and flexibility
Some loss of hearing and vision
What sort of gait changes are seen in the elderly?
Reduction in velocity
Reduction in stride length but increase in steps
Decreased
- arm swing
- rotation of the pelvis
More flat foot approach to heel strike and push off
Where does the centre of gravity lie when standing?
Anterior to S2 vertebra
Means line of gravity is:
- slightly posterior to hip joints
- anterior to knee and ankle joints
The line of gravity passes anterior to the ankle joint, this results in a ‘forward sway’? How is this counteracted?
By contraction of plantar flexor muscles
- particularly soleus
What are the phases of the gait cycle?
Stance phase
- foot in contact with ground (60%)
Swing phase
- foot is in the air (40%)
Double support
- both feet on the ground (10%)
What are the subdivisions of the stance phase?
- Heel strike
- Loading response
- Mid-stance
- Terminal stance
- Pre-swing
What are the subdivisions of the swing phase?
- Initial swing
- Mid-swing
- Terminal swing
What is a dynamic contraction?
Muscle contracts with a change in length.
- Concentric
- Eccentric
What is a concentric contraction?
Muscle shortens while contracting
What is an eccentric contraction?
Muscle lengthens while contracting.
What is an isometric contraction?
Muscle contracts without changing in length.
Which muscles are involved in the heel strike?
Lowering of forefoot to the ground is controlled by eccentric contraction of tibialis anterior
Deceleration of forward momentum – achieved by hip extension by gluteus maximus
Preservation of longitudinal arch of foot by intrinsic muscles
Ankle and subtalar joints accommodate terrain
What are the features of the loading response?
Foot comes into full contact with ground
Requires knee extension to prevent knee buckling under weight – quadriceps femoris
Continued hip extension and preservation of longitudinal arch
What is the midstance part of the gait cycle?
Point at which opposite limb swings past stance limb.
Which muscles are involved in the mid-stance part of the cycle?
Requires stabilisation of the pelvis to keep it level – abduction of hip
Achieved by contraction of:
- gluteus medius
- gluteus minimus
- tensor fasia lata
What is the terminal stance?
Point at which the heeal starts to lift off the ground
Which muscles are involved in the terminal stance part of the cycle?
Achieved by plantar flexors – soleus and gastocnemius
This also accelerates mass forward
What is the pre-swing (toe-off)?
Final stage of stance phase – preparation for moving into swing phase
How is the pre-swing achieved?
Powerful plantar flexion of digits to push off ground and accelerate mass forward
Slowing of hip extension and preparation for hip flexion – eccentric contraction of rectus femoris
What is essential for toe-off and what is it stabilised by?
Hallux
Stabilised by
- adductor hallucis
- abductor hallucis brevis
What sort of gait problems may result from a misaligned or missing hallux?
Weak push off (apropulsive gait) results in:
- shorter stride length
- decreased gait velocity
Which muscles are involved in the initial and mid-swing?
Hip flexion carries limb forward
- iliopsoas
- rectus femoris
Toes & foot dorsiflexed to allow foot to clear the ground
- tibialis anterior
Aided by knee flexion to shorten limb
- hamstrings
What happens during the terminal swing?
Knee flexion changes to extension to place foot in correct position ready for heel-strike
- quadriceps
Assisted by dorsiflexion of ankle
- tibialis anterior
Simultaneously, eccentric contraction of hamstring muscles decelerates limb in preparation for heel-strike
What happens if an individual is unable to flex their knee?
Limb circumduction
- swinging leg moves in an arc rather than straight forwards
- increases ground clearance for the swing foot
If the foot cannot be dorsiflexed which nerve is most likely damaged?
Due to paralysis of tibialis of anterior
- common peroneal (fibular) nerve
Pelvic rotation reduces the vertical drop in centre of gravity. What muscles achieve this?
Stance Limb: internal rotation
- Gluteus medius and minimus
- Tensor fascia lata
Swing Limb: external rotation
- Piriformis
- Quadratus femoris
- Obturator internus and externus
- Superior and inferior gemelli
What limits the vertical rise in centre of gravity during the gait cycle?
Knee flexion
Pelvic drop to swing side
What are the causes of a Trendelenberg gait?
Stroke
Hip Osteoarthritis
Cerebral Palsy
Superior gluteal nerve damage
What minmises the lateral shift in centre of gravity?
Adductors pull the knees into midline to limit lateral shift in gravity
