Module 11: Posture and Balance Control Flashcards
What does the LOG pass through in upright posture?
Thru mastoid process, anterior to shoulder joint, posterior to the hips, anterior to the knee, anterior to the ankle
What is the BOS in upright stance?
The feet, spread between anterior transverse arch, lateral longitudinal arch, medial longitudinal arch
Describe the changes that happen in posture when one changes from standing to sitting?
The COG lowers in space but rises in relation to the body
- BOS is increased and put thru sit bones
- pelvis is in posterior tilt
What is the characteristics of laying posture?
no energy expenditure
large BOS and low COG
3 types: supine, side laying, prone
Describe the different areas where one would expect to find sores if they spent significant amounts of time in each type of laying posture?
Supine: occipitus, scapula, spinous process, sacral bone, ischial tuberosity, heels
Prone: knees, chin, face, stomach
Side laying: Ears, shoulders, hip, ankle
Describe the differences in the posture of babies when compared to adults.
Babies have a concave spine, the convex development begins when the head has to work against gravity
- COG is higher because of larger heads, BOS is also wider
Describe the changes that occur from childhood to adulthood in posture?
age 6: foot arches and spinal curves become similar to adults
adolescence: imbalance btwn bone growth and soft tissue growth can lead to abnormalities
adulthood: work and prolonged forced postures lead to muscle and joint dysfunction (decreases ROM, kyphosis, etc)
What are the characteristics of scoliois?
lateral curvature of the spine, muscles on the concave side are shorter, muscles on the convex side are longer and weak
What are the characteristics of hyperkyphosis?
anterior curvature of the spine, can lead to increased cervical lordosis and impacts shoulder function, can impact lung function if becomes severe enough
Characteristics of hyperlordosis?
increased curvature in the lumber/cervical spine, seen often during or after pregnancy
- can implicate gluteal and core musculature
- often accompanied by anterior pelvic tilt
Characteristics of swayback posture?
slouchy, pelvis forward, knees hyperextended, increased lumber lordosis and thoracic kyphosis
- uses the least amount of energy (relies on soft tissues and ligaments)
Characteristics of flat back posture?
increased posterior pelvic tilt and decrease lumber lordosis, can lead to hyperextension of the knees and lengthened hip flexors
Describe the role of the vestibular system in maintaining posture?
- head orientation in relation to gravity, linear and angular accel of the head
- sensory receptors provide constant info about head position thru the vestibulocochlear nerve (CN8)
Describe the role of the visual system in maintaining posture?
- provides info regarding body orientation, relationship between parts and motion of body in relation to other things
- info transmitted by the optic nerve (CN2)
Describe the role of the somatosensory system in maintaining posture.
- provides info about body position thru joint receptors, muscle spinles and mechanoreceptors
- is active subconciously
Explain the differences between the 2 theories of sensory integration.
Intermodal theory: all 3 inputs contribute equally and at all times
Sensory weighted hypothesis: CNS modifies the input based on the perceived accuracy
Describe the differences between anticipatory and compensatory balance control.
Anticipatory: signals for postural compensation go before the movement happens (allows for preparation)
Compensatory: makes adjustment after the movement happens (posture constantly being challenged by external forces (not all can be predicted)
Provide and example of both anticipatory and compensatory balance control.
Anticipatory: picking up a heavy object from the floor
Compensatory: grabbing the pole after a bus starts to move
What are the mechanisms of compensatory balance control?
Ankle strategy, hip strategy and stepping strategy
Describe the ankle strategy.
used to correct small perturbations in COG
- backwards sway = tibialis anterior will act to bring COG anterior
- forwards sway = gastroc acts to bring COG posterior
Describe hip strategy.
- larger perturbations in balance
- forward sway = abs and quads act to move the body backwards
- backwards sway = hamstrings and paravertebral muscles act to bring body forwards
Describe the stepping strategy.
- used in the perturbation forces COG outside the BOS
- a step is taken to widen the BOS
Describe the movements used to restore balance in other directions.
Medio-lateral: hip and trunk
Multidirectional: synergy of muscle patterns activated to regain balance
What are some of the factors that increase the loss of balance?
disturbances to sensory, nervous, muscoluskeletal systems
ageing: flexibility and strength decrease, sensory system function decreases, nerve conduction decreases
