Group D - S-curve with upper spine (C2-C4) showing lordosis and lower spine (C5-7) showing kyphosis
Group D - S-curve opposite to Group D with upper spine kyphotic and lower spine lordotic.
Why is spinal posture important
Alterations in spinal posture via translatory motions also affect the kinematics of the spine.
What is the difference between men and women in seated positions in terms of lumbar posture and location on the seat itself.
In general females demonstrated more pelvic anterior tilt, less lumbar flexion and less overall trunk flexion than the males. In chairs with back rests males tended to lean against the back rest while females sat closer to the front part of hte seat.
What is the problem with kyphosed sitting postures?
They can lead to cumulative damage to soft tissues of the spine.
What does the research say about posture and shoulder ROM
Changing posture causes a significant increase in the ROM in shoulder flexion and abduction in the plane of the scapula. Changing posture did not have an effect on the intensity of pain but did affect the point in the range of shoulder elevation at which the pain occurred (significantly higher).
Does thoracic posture have an affect on the kinematics of the scapula?
Yes, increased thoracic kyphosis significantly alters the kinematics of the scapula during humeral elevation.
Can posture be changed?
Yes, through programs of exercise and stretching.
Line of gravity: an imaginary vertical line from CoM to center of earth; if LoG is accurately represented, can be vector quantity.
What is important to remember of where the LoG falls in relation to the joint and joint axis
It helps to determine the external moment that will be produced and subsequent internal moment from muscle action needed (if any) to maintain posture
In the saggital plane what happens if the LoG passes anterior to the axis?
Line of action of the fore will try to create anterior motion of the proximal segment acting on the joint.
In the saggital plane what happens if the LoG passes posterior to the axis?
Line of action of the force will try to create posterior motion of proximal segment acting upon that joint.
In the frontal plane what happens when the LoG passes lateral to the axis?
Line of action of the force will try to create lateral motion of the proximal segment supported by that joint.
In the frontal plane what happens when the LoG passes medial to the axis?
The line of action of the force will try to create medial motion of the proximal segment supported by that joint.
Contact with te ground in turn results with the ground reacting or pushing back.
In the sagittal plane what happens when the GRFv passes anterior to the axis?
The line of action of the force will try to create anterior motion of the distal segment acting on that joint.
In the sagittal plane what happens if the GRFv passes posterior to the axis?
The line of action of the force will try to create posterior motion of the distal segment acting upon that joint.
In the frontal plane what happens when the GRFv passes lateral to the axis?
The line of action of the force will try to create lateral motion of the distal segment supported by that joint.
In the frontal plane what happens when the GRFv passes medial to the axis?
The line of action of the force will try to create medial motion of the distal segment supported by that joint.
What are the LoG locations in relationship to body segments in sagittal view?
Head: through external auditory meatus, through ear lobe and odontoid process. C-spine: Posterior to the axis and through the vertebral bodies T-spine: Anterior to axis, anterior to vertebral bodies L-spine: Posterior to axis through vertebral bodies SI joints: Slightly anterior to SI joint Hip: Slightly posterior to axis through the greater trochanter Knee: Anterior to midline (and axis) of knee, posterior to patella Ankle - Slightly anterior to lateral malleoulus
How can you determine a neutral position for the pelvic bone?
Line between ASIS and PSIS is roughly horizontal (compare on both side)
Line between outer surface of ASIS and tip of pubic symphysis is (near) vertical.
For both of the above you are looking for something very distinct and very evident, not slight differences.
What are the LoG locations in relationship to body segments in frontal view?
Symmetry between L and R sides
Joint axes of hip, knee, and ankle are equidistant from the LoG
Midline of occiput, through spinous processes of all vertebra and directly through gluteal cleft
Shoulders/hips level to horizontal.
What are the postural deviations to look for that will occur in the transverse plane?
You should expect symmetry in rotations. If viewed from above - shoulders and pelvis should be in line with each other, no anterior or posterior rotation in static position. Humerus and femurs shoudl be symmetrical.
Define the kinetic chain
Have to consider positions of entire body especially trunk, pelvis, and foot when examining function or static/dynamic response of a segment/joint (Research traditionally just examined single joint).
Define active erect sitting
An unsupported posture in which a person attempts to sit up as straight as possible.
What are different attributes of active erect sitting?
Purposeful muscle activity to accentuate the posture.
Requires greater muscle activity from the trunk musculature to maintain active erect sitting posture than slumped sitting posture
Lumbar interdiskal pressures (L3-L4 or L4-L5) higher or as high in active erect sitting than in standing
Where do the lowest interdiskal pressures and lowest EMG readings occur which sitting?
Seat back inclinations between 110 - 130 degrees
Combined with lumbar support that protrudes 5cm from back of the seat back
Posterior seat inclination of 5 degrees
Using armrests produces further reductions
Define seat interface pressure
Contact between person's body and seat.
Indicator of subcutaneous stress.
Extremely important to consider in certain populations.
Cushions can be helpful.
Define postural control
Person's ability to maintain stability of the body and body segments in response to forces that threaten to disturb the body's equilibrium.
What is static postural control?
Maintain posture in certain positions
What is dynamic postural control?
Maintain stability during movement or change in supporting surface.
What is another term used to describe static postural control?
"Quiet stance" because there is sway occurring and not static by some definitions.
What are the 6 factors that influence the postural response?
Size of the supporting surface
Direction of motion of platform
Location of push-pull forces
Magnitude of force applied
Initial posture prior to applied force
Velocity of applied force
Define fixed support synergies
Patterns of muscle activity that occur as a result of a perturbation in which the BOS remains fixed during the process of recovery to equilibrium; body moves, feet don't move
Define the Ankle Pattern
Discrete bursts of muscle activity on either anterior or posterior portions of body that occur in a distal-to-proximal response to forward-backward movement of platform. (ankle, then hip, then trunk and neck).
Define Hip Pattern
Produced muscle response opposite to that of ankle pattern in proximal-to-distal pattern of activation (abs, then quad, then anterior tib).
Define claw toes
Deformity characterized by hyperextension of MTP with flexion of PIP and DIP
Define Hammer Toe
Deformity characterized by hyperextension of MTP joint, flexion of PIP and extension of DIP. (always look at callouses, blisters - always examine feet).
What is the importance of GRFv?
Where the GRFv falls in relation to the joint and joint axis helps determine external moment that will be produced and subsequent internal moment from the muscle action that is needed (if any) to maintain posture.
Define balance (according to Chinworth)
The integration of systems whose ultimate goal is to maintain static or dynamic stability.
Define stability (Chinworth)
Degree to which one can stand still or move without falling (full body).
Define stabilization (Chinworth)
= joint stability = provides a good length-tension relationship and a good foundation for movement and load distribution (e.g. trunk stabilization).
What are the three goals of postural control in erect posture?
Maintain and control body's orientation in the space in which the body is located.
Maintain CoM (LoG) within BOS
Stabilize the head for appropriate eye gaze (righting response).
What are the 4 conditions for full body stability?
The line of gravity within the BOS
Larger the base of support, more stable
The lower the CoM is to the BOS the more stable.
The closer to the center of the BOS that the LoG falls, the more stable.
What are the 5 things on which the maintenance or control of full body stability depend on?
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