Section 2 - Posture

They can lead to cumulative damage to soft tissues of the spine.

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).

Yes, increased thoracic kyphosis significantly alters the kinematics of the scapula during humeral elevation.

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.

It helps to determine the external moment that will be produced and subsequent internal moment from muscle action needed (if any) to maintain posture

Line of action of the fore will try to create anterior motion of the proximal segment acting on the joint.

Line of action of the force will try to create posterior motion of proximal segment acting upon that joint.

Line of action of the force will try to create lateral motion of the proximal segment supported by that joint.

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.

The line of action of the force will try to create anterior motion of the distal segment acting on that joint.

The line of action of the force will try to create posterior motion of the distal segment acting upon that joint.

The line of action of the force will try to create lateral motion of the distal segment supported by that joint.

The line of action of the force will try to create medial motion of the distal segment supported by that joint.

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

• 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.

• 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.
  

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. 

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).

An unsupported posture in which a person attempts to sit up as straight as possible.

1. Purposeful muscle activity to accentuate the posture.
2. Requires greater muscle activity from the trunk musculature to maintain active erect sitting posture than slumped sitting posture
3. Lumbar interdiskal pressures (L3-L4 or L4-L5) higher or as high in active erect sitting than in standing
   

• 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
  

• Contact between person's body and seat. 
  
• Indicator of subcutaneous stress. 
  
• Extremely important to consider in certain populations. 
  
• Cushions can be helpful.

Person's ability to maintain stability of the body and body segments in response to forces that threaten to disturb the body's equilibrium.

Maintain posture in certain positions

Maintain stability during movement or change in supporting surface.

"Quiet stance" because there is sway occurring and not static by some definitions.

1. Size of the supporting surface
2. Direction of motion of platform
3. Location of push-pull forces
4. Magnitude of force applied
5. Initial posture prior to applied force
6. Velocity of applied force
   

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

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).

Produced muscle response opposite to that of ankle pattern in proximal-to-distal pattern of activation (abs, then quad, then anterior tib).

Deformity characterized by hyperextension of MTP with flexion of PIP and DIP

Deformity characterized by hyperextension of MTP joint, flexion of PIP and extension of DIP. (always look at callouses, blisters - always examine feet).

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.

The integration of systems whose ultimate goal is to maintain static or dynamic stability.

Degree to which one can stand still or move without falling (full body).

= joint stability = provides a good length-tension relationship and a good foundation for movement and load distribution (e.g. trunk stabilization).

1. Maintain and control body's orientation in the space in which the body is located.
2. Maintain CoM (LoG) within BOS
3. Stabilize the head for appropriate eye gaze (righting response).
   

1. The line of gravity within the BOS
2. Larger the base of support, more stable
3. The lower the CoM is to the BOS the more stable.
4. The closer to the center of the BOS that the LoG falls, the more stable.
   

1. CNS
2. Visual system
3. Vestibular system
4. Musculoskeletal system
5. Joint receptors