Posture Flashcards
What is “Line of Gravity”?
A point from the center of mass perpendicular to the ground (pushing down)
What is “Ground Reaction Force”?
Force pushing upward against our contact with the floor
What factors influence posture?
- Body Type
- Habit
- Disease
- Genetic anatomical predisposition
What is posture?
The orientation of body segments to each other in a STATIC position
What are the primary forces acting on the body?
Body weight
Ground reaction force
Explain what happens at each joint in Standing Posture.
Gravity creates an external moment that is resisted by an internal moment
What is the external moment in Standing Posture?
The line of gravity
What is the internal moment in Standing Posture?
The counter active muscle force
What is the resultant force vector on the feet in Standing Posture?
The center of pressure
What does the Ideal Line of Gravity do for the vertebral column?
Help maintain optimal shape of each curve
In which directions does the Line of Gravity produce torques in the vertebral column?
Alternating flexion and extension
What factors alter the relationship of the Ideal Line of Gravity?
Fat deposition Specific shapes of spinal curves Posturing of head and limbs Muscle strength and endurance Connective tissue extensibility Position and magnitude of loads
What muscles are active during Quiet Stance?
Erector Spinae (counteracts anterior movement) Gluteus Medius & TFL (controls lateral pelvic tilt) Soleus (maintain upright position) Iliopsoas (constantly active)
What muscles are quiet during Quiet Stance?
Abdominals Gluteus Maximus Feet Upper Trapezius (minimal activity) Serratus Anterior (minimal activity) Supraspinatus (minimal activity) Posterior Deltoid (minimal activity) Quadriceps (slight activity at times) Hamstrings (slight activity at times)
What are the types of Postural Alignment?
Ideal Alingment
Kyphosis-lordosis posture
Flat-back posture
Sway-back posture
What are the factors that can impact spinal alignment?
Disease
Trauma
Advanced age or reduced activity
What is an example of a disease that can impact spinal alignment?
Ankylosis spondylitis
Polio
What is an example of trauma that can impact spinal alignment?
Vertebral fracture
Spinal cord injury
What is an example of advanced age or reduced activity that can impact spinal alignment?
Osteoporosis
Muscle weakness
What are the associated problems with abnormal curvature of the spine?
Increased stress on muscles, ligaments, bones, disc, facet joints, and exiting spinal nerve roots
Changes the volume of body cavities
What posture does this describe: forward head with extension of the cervical spine; backward trunk displacement; increased kyphosis; flattening of lumbar spine; posterior pelvic tilt; hyperextended hips and knees
Swayback posture
What is the purpose of Postural Control?
To control your body position in space for ORIENTATION and STABILITY
What is Postural Control?
The 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 Postural Orientation?
The ability to maintain an appropriate relationship between the body and body segments and environment for a given task.
Postural orientation ~ posture
What is Postural Stability?
The ability to control the center of mass in relation to the base of support. (Location and velocity of COM is important)
Postural stability = balance
Where is the location of the center of gravity or center of mass (used interchangeably)?
S1/S2
What is Limits of Stability?
The distance in any direction a subject can lean away from mid-line without altering the base of support
What determines the Limits of Stability?
Firmness of BOS
Strength and speed of muscular responses
Range (8 degrees anteriorly; 4 degrees posteriorly)
