Gait and posture Flashcards
What is gait?
Cyclical activity that translocates the centre of the body mass in a forward direction e.g. walking or running
Generally symmetrical and rhythmic but each gait differs from person to person
what is bipedalism?
Walking on two limbs
Why did hominids develop bipedalism?
- becoming taller to see more of the landscape
- using upper limbs for climbing
- greater movement economy on the ground
everybody has a unique gait because gait depends on:
Stride length – determined by by height / leg length
Pelvic movement
Upper body position
Weight and weight carriage
Clothing
Shoes / footwear
Age
Normal gait depends on:
Vestibular system
Peripheral nerves
visual system
Motor pathways
Basal ganglia = initiation of movement and coordination of movement
Reflexes and muscle tone being pain free
The role of standing in gait
supports body weight
minimises energy expenditure
Where is the centre of gravity?
The centre of gravity =
anterior to S2 vertebra
slightly posterior to the hips
anterior to knee and ankle
What is the most stable position of the knees and hips
Extension (not bent)
In standing, the tendency to fall forward is called
sway
This is counteracted by contraction of soleus
What is muscle tone and what are the changes of muscle tone called?
Muscle tone is a feature of skeletal muscle – in the limbs and body wall that is deemed the “firmness”
Hypotonia = reduced muscle tone - ’floppy’
Hypertonia = increased muscle tone - ‘spasticity’ and stiffness
Why is muscle tone important?
It helps to stabilise joints and maintain our posture
What systems control muscle tone and posture?
sensory inputs, spinal reflexes, descending tracts; the vestibular system and the vestibulospinal tracts important for standing upright
Cerebellar outputs to brainstem and cerebral cortex also involved in postural control.
What are the 2 phases of the gait cycle?
Stance phase (foot in contact with ground; 60% cycle)
Swing phase (foot is in the air; 40% cycle)
What is stance phrase comprised of?
Heel strike Loading response Mid-stance Terminal stance Pre-swing
What is swing phase comprised of?
Initial swing
Mid-swing
Terminal swing
2 types of muscle contraction are:
Isotonic: concentric (shorten) and eccentric contraction (Relax and lengthen)
Isometric: increase in tension of the muscle but it doesn’t change length and there is no movement
Heel strike
Begins when the heel strikes ground
Lowering of forefoot to the ground is by the controlled lengthening / relaxation (eccentric contraction) of tibialis anterior
Deceleration of forward momentum due to hip extension (gluteus maximus)
Ankle and subtalar joints accommodate terrain
loading response
Foot comes into full contact with ground
Body weight is transferred to stance limb
Quadriceps femoris is key in extending and stabilising the knee and preventing the knee from buckling under the body weight
Midstance
Opposite limb swings past stance limb
Requires stabilisation of the pelvis to keep it level – achieved by abduction of hip on stance side by gluteus medius and minimus
terminal stance
Heel of the stance limb starts to lift off the ground
Achieved by the plantarflexors – soleus and gastrocnemius
This also accelerates mass forward
Pre swing
Final stage of stance phase – preparation for moving into swing phase (i.e. prep for this limb leaving the ground and swinging forward)
Powerful plantarflexion of the digits to push off the ground and accelerate mass forward
In preparation for hip flexion, rectus femoris starts to relax / lengthen (eccentric contraction)
Hallux is essential for:
toe off
stabilised by adductor hallucis and abductor hallucis brevis
Weak push off (‘apropulsive’ gait) from the toe results in:
shorter stride length
decreased gait velocity
initial and mid swing
Hip flexion carries limb forward – iliopsoas and rectus femoris are active (shortening)
Toes & foot are dorsiflexed to allow the foot to clear the ground – tibialis anterior active
Plus knee flexion to shorten limb – hamstrings shorten
Terminal swing
In preparation for landing the foot on the ground for heel strike the foot is positioned: to land the foot on the ground: flexed knee is now moved into extension (shortening of the quads, relaxation of the hamstrings – the latter decelerates the limb))
Dorsiflexion of ankle (tibialis anterior) ensures toes clear the ground
vertical shift is minimised by
hip abductors
lateral shift is minimised by
hip abductors
why does gait change with age?
Reduced muscle bulk
Reduced strength and flexibility
Some degree of hearing and vision impairment
how do elderly increase gait velocity?
elderly tend to take more steps instead of increasing stride length
Also decreased arm swing and rotation of the pelvis
More flat-footed approach to both heel strike and push off
What are the 9 major classifications of gait abnormalities?
Cerebellar ataxia Hemiparetic gait Diplegic gait (spastic hemiplegia) Parkinsonian gait Sensory ataxic gait Steppage gait Myopathic gait Antalgic gait Functional gait
How do you identify cerebellar ataxia (key characteristics) and what causes it?
Unsteady gait
Incoordination and difficulty with balance
Tendency to jerk sideways
Struggle to narrow feet - appear broad
Can be caused by:
- midline cerebellar lesions that cause truncal ataxia
- chronic alcoholism that leads to cerebellar degeneration
How to identify hemiparetic gait and what causes it?
Appearance shows on the affected side
Flexion of the elbow and extension of the lower limb
(affected side appears to be drawing circles with their foot)
the affected limb cannot be shortened by knee flexion when walking
How to identify diplegic gait and what can cause it?
Lower limbs are stiff and the hips are adducted
The legs may appear to cross each other and knees seem inverted
Can be caused by:
- cerebral palsy
- MS
- MND
what does the Parkinsonian gait appear like?
Shuffling, small steps, difficulty initiating and stopping movement.
When the patient starts walking, their pace increases
Caused by:
- degeneration of the dopamine-producing neurons of the substantia nigra.
- Leads to a combination of rigidity,
- bradykinesia (poverty of movement)
- tremor
What does sensory ataxic gait look like and what can cause it?
caused by impaired proprioception
broad based (feet wide apart) and unsteady
Sometimes shows as stomping feet
Positive romberg test: when patient closes their eyes they begin to sway as they cannot depend on their vision
What does steppage/neuropathic gait look like?
What can it be caused by?
Weakness of the muscles of the anterior compartment of the leg that dorsiflex the foot = footdrop.
Patients are unable to dorsiflex the ankle of the swing limb and the toes don’t clear the ground
How do patients with steppage/neuropathic gait compensate
Flexion of the hip and knee on the affected side so the foot clears the ground.
myopathic gait appearance and can be caused by…
waddling appearance
proximal lower limb muscles are weak > unable to maintain level position of the pelvis when one leg leaves the ground
can be caused by muscular dystrophies
trendelenberg gait is caused by
Paralysis of the hip abductors of one side (e.g. due to superior gluteal nerve palsy)
Antalgic gaits
An antalgic gait occurs secondary to pain
patients cannot put weight onto painful limb
functional gaits
‘Non-organic’: i.e. psychological
highly variable presentation that doesn’t fit into any of the other categories
