Control of Lower Limb Movements and Common Gait Problems Associated with Neurological damage Flashcards
Aims
- Review features of applied anatomy that permit the role of the lower limb in human function
- Explain the control of unilateral (discrete) and reciprocal (continuous/cyclical) lower limb movements.
- Explain the common problems affecting gait and lower limb movement in central and peripheral nervous system disorders.
What is the role of lower limb?
- Maintenance of erect posture- enables upper limb function
- Absorption/ transmission of forces involved in weight bearing
- Mobility- stance, stairs, walking
Define posture
Biomechanical alignment of the body and its orientation to thee environment.
In quiet stance where does the centre of gravity (COG) fall?
anterior to hip or posterior and so on for knee and ankle joint. so its a 3 point answer
- In quiet stance the line of centre of gravity falls
- posterior to hip joint
- anterior to knee joint
- anterior to ankle joint.
In quiet stance, the postural alignment of the lower limb is supported by which structures?
- Hip: ilio-femoral ligament/iliopsoas
- Knee: posterior joint capsule
- Calf: gastrocnemius/ soleus
What are the roles of;
- Active restraints
- Passive restraints
In the maintenance of posture?
- active restraints enable dynamic correction of postures
- passive structures minimise energy expenditure.
Bone structure; what are the 2 types of bone?
- Compact: around the head of femur and on the exterior of the femur
- Cancellous: usually internal, is porous.
Lower limb structures are subjected to different forces in a weight bearing position, what are these forces?
- HAT = head, arms and trunk.
- As well as Ground reaction force.
What are the 2 types of bone/ bone structures.
- Compact: around the head of femur and on the exterior of the femur
- Cancellous: usually internal, is porous. much lighter helps absorb forces and direct it away from certain areas, SEE RECORDING
What is the role of the;
- Meniscus
- Made of fibrocartilaginous material which helps the absorption and transmission of forces
- Helps increase the congruence (contact) between the femur and tibia, which helps with stability.
During a gait cycle what is the COG like?
And what affects the COG?
- During gait, the COG traverses a sinusoidal curve (goes up and down like a sound wave).
- The displacement of COG is kept to a minimum to reduce energy expenditure as well as to minimise the amount of shock on the joints.
- So reducing the amount the COG shifts it reduces the amount of shock to the lower limb and saves energy.
What are the key determinates of Gait for the Pelvis?
- Pelvic rotation; Alternative left and right rotation –> decreases vertical COG displacement
- Pelvic tilt; Tilts downwards on swing leg (by 5 degrees) –> decreases vertical COG displacement
- Lateral pelvic rotation; Horizontal shift on pelvis with relative hip abduction to stance phase. Prevents excessive lateral weight shift.
What are the key determinates of Gait for the Knee?
Go through position of knee, flexion and extension degrees in the different phases of the gait cycle.
Knee flexion in mid-stance; 15-20 degrees during loading response –> decreases vertical COG displacement, also acts as shock absorption.
- Foot, ankle and knee motions;
- Ankle is dorsi flexed while knee almost fully extended in early stance phase.
- Prevents further downward displacement of COG.
- Ankle is plantarflexed while knee begins to flex in stance phase.
- prevents further downward displacement of COG.
Define a Gait cycle.
The initial contact of one foot until that foot makes contact again with the ground.
In a gait cycle, what is the right step length
and left step length?
R step length = base of left foot to base of right foot.
L step length = base of right foot to base of left foot.
Do men or women have a larger toe out angle in their gait?
Men
Do men or women have a longer step length?
Men.
because men are generally taller than women, and its based off height
What are the three main roles of the lower limb during human function?
- maintenance of posture
- transmitting forces
- locomotion
Why is it important to reduce the displacement of the COG during walking?
- Energy efficient.
- Reduces forces to spinal cord, nerves and lower limb
What situations change normal step length and walking speed?
- Age (walking speed)
- Height
- Neuro conditions/ comorbidities
- Any condition affecting balance
- Patients mood
- Footwear
Discrete movements
- recognizable beginning and end
- wend point is an inherent attribute of the task e.g. kicking, throwing sit-stand
Continuous movement
- no recognizable beginning or end
- end point of task is not an inherent characteristic of the task but is decided arbitrarily by the performer e.g. swimming, walking, running, swimming etc.
What are Central pattern generators.
Very long answer 4 points
- Intrinsic spinal networks of neurons capable of generating cyclical, repetitive movement.
- Responsible for the complex coordination of muscle contractions needed to generate rhythmic stepping movements of the legs.
- rhythmic alterations of flexion & extension during swing and stance phases consist of differentially timed & spatially distributed synergy of muscle contraction.
- Receive input from higher centres and peripheral/sensory feedback to modulate the stepping pattern.
What lobes are responsible for different parts of control of walking?
- Frontal lobe
- Parietal lobe
- Occipital lobe
- Temporal lobe
- Cerebellum
- Basal ganglia
- Brainstem
- Frontal lobe;
initiation, planning the motor execution that’re involved in walking. - Parietal lobe;
Sensory lobe so integrates the sensory information from somatosensation. so detecting muscle length as well as tactile sensation associated with putting our feet on the ground and different surfaces. - Occipital lobe;
Visual lobe so, helps us respond to visual stimuli, like threats within our field of vision. - Temporal lobe;
Important for the topographical, 3D orientation of our body associated with walking. - Cerebellum;
Co-ordination of movements, the fine tuning of the gait pattern. - Basal ganglia;
Part of the motor planning aspect, also a key component where making choices between decisions when we walk e.g. walking through a door do we turn left or right after we pass through. - Brainstem;
Within the brainstem we have a locomotor centre, this is where the first supraspinal control of walking above the spinal cord level.
