theoretical background of postural...

THEORETICAL BACKGROUND OF POSTURAL CONTROL

Postural Control – Role In The Human Movement

대전 보람병원

이기훈

2015 한국보바스 소아학술대회

Key word

• Postural control : 중력에 대응공갂에서 자세를 유지어떤 동작을 수행이 가능하도록 하는 배경보행이나 manual skill 발달의 기초

• 중추신경계- 공갂에서의 신체의 위치와 움직임에 대한 정보를 제

공하는 많은 감각 정보를 받아들임.- 통합- 여러 조절단계- 몸통 및 사지의 귺육에 적절한 수축과 이완 유도

Key word

• Vestibular system

• Muscles which locate around the neck are most important, which is the basis for the postural control of human movement

• The top is the head which is the keystone of the central line

Gravity

Human Movement

• The same way to move against gravity

• Normal postural control mechanism

• All of these are all generated postural control, without conscious control

Terminology

• Postural control: the ability to control the body’s position in space for the dual purposes of orientation and stability

1) Orientation: the ability to maintain appropriate task-specific relationships between the body segments and between the body and the environment

2) Stability: the ability to control the center of mass relative to the base of support

3 components of postural control mechanism

- Normal postural tone

- Reciprocal innervations

- Common movement pattern (learned pattern)

Human movement – postural tone

• Postural tone generated by changes in the

location of the head

- move on the same axis against the BOS

- activate the neural system of the brain

Human movement – reciprocal innervations

• Reciprocal innervations

- Agonist, antagonist, synergist

- Proximal stability, distal mobility

Human movement- common movement pattern

• Previous information, current information

• Adaptive, anticipatory

Postural tone

• In daily life, human keep working against

gravity to maintain the head in the axis

• Postural tone starts to work from the moment

the head in space

Terminology

• Tone : resistance of muscle to stretch

phasic and postural

• Phasic tone – rapid contraction in response to a high- intensity

stretch, as in tendon reflex response

• Postural tone – prolonged contraction of antigravity muscles in

response to the low-intensity stretch of gravity. When postural

tone is depressed, the trunk and limbs cannot maintain

themselves against gravity

Postural tone

• An appropriate activation of muscle of the

body to maintain the head & body on midline

against gravity

• Information tools which are the vestibular

network of eye, inner ear, muscle spindles of

the neck and trunk

Mechanisms for modulation of postural tone

• Postural tone automatically works to

allow head movement in space in order

to do something with volition

Mechanisms for modulation of postural tone

• Standing

• Soldier – military standing at attention

• Lying down in bed

• Initial wakefulness with opening of eye

• Sitting

Mechanisms for modulation of postural tone

• Straightened neck with 2 columns of upper trapezius

The Neck

• Muscles which locate around the neck are most important, which

is the basis for the postural control of human movement

• It works with vestibulospinal reflex, vestibulocollic reflex,

vestibuloocullar reflex

• For connecting with vestibular neural network, neck muscles are

composed of highest density of muscle spindle then other

muscles

Mechanisms for modulation of postural tone

• Hemiplegia – muscle weakness, hypertonus SCM, upper

trapezius column weakness or disappearance

• Premature diplegia – low proximal tone

• Weak or shortened neck

-inability to watch with two eyes and to straighten the neck

Basis of neural network for the modulation of postural tone

• Otolith, the utricle and saccule.

- LVN

- ipsilaterally extensor m. in the cervical & lower lumbar

segment of spinal cord

• Semicircular canal

- MVN

- bilaterally cervical or upper thoracic of spinal cord

- extensor m. facilitation, flexor m. inhibition

Netter ‘97

Basis of neural network for the modulation of postural tone

• Vestibular nuclei

1. Sensory information about head movement &

head position relative to gravity

2. Gaze stabilization

3. Postural adjustment

4. Autonomic function and consciousness

Model ComponentsSensory Organization

• Balance/postural control via

three systems:

– Somatosensory

– Visual

– Vestibular

Somatosensory System

• Dominant sensory

system

• Provides fast input

• Reports information

– Self-to-(supporting)

surface

– Relation of one

limb/segment to another

• Components

– Muscle spindle

• Muscle length

• Rate of change

– GTOs

• Monitor tension

– Joint receptors

• Mechanoreceptors

– Cutaneous receptors

Vestibular System

• Not under conscious

control

• Assesses movements of

head and body relative to

gravity and the horizon

(with visual system)

• Resolves inter-sensory

system conflicts

• Gaze stabilization

• Components

– Cerebellum

– Projections to:

• Brain stem

• Ear

Sensory-Motor Integration

Somatosensory

Vestibular

Visual

Eye Movements

Postural Movements

10 Processor

20 ProcessorCerebellum

Motoneurons

Sensory Input Processing Motor Response

Normal Postural ControlSensory System

• The somatosensory system provides information

about the body with reference to supporting

surfaces.

• The somatosensory system receives information

from muscle spindles, joint receptors, tendon

organs, and mechanoreceptors.

Basis of neural network for the modulation of postural tone

• Modulation Of Postural Tone

• Higher Position

Basis of neural network for movement of the body

• Standing

• The top is the head which is the keystone of the central line

• Vestibular system contributes to the generation of postural

tone regarding to the location of the head for maintaining

posture and for preparing the body movement

Basis of neural network for movement of the body

• In sitting: gluteus maximus initiator of respond the change

of head location

• Rest a sofa

- head flexed, body lean backward

• Sacrum sitting

• When intend to do something

- head higher, pelvis upright, gluteus maximus, back m

extension

Basis of neural network for movement of the body

• The most important consideration is the

adequate & right activation of the head

• Gluteus maximus

Basis of neural network for movement of the body

• For another instance

- human stand up

• Head flexion, proximal m. flexion

• Pelvis automatically ant. tilting

- leg flexion – for supporting the weight of the head & the

body

Special consideration body parthuman movement

1. Eye with the head

2. Neck dynamic stability

3. Shoulder joint

4. Hand

5. Proximal dynamic stability

6. 3-dimensional pelvic movement

7. Ankle, foot

CERVICAL AND THORACIC

SPINE

HAND MOVEMENT

PROXIMAL DYNAMIC STABILITY

3 – DIMENSIONAL PELVIC MOVEMENT WITHOUT or WITH BOS

THE PELVIS MOVES ONTO THE HIP JOINT

FOOT /ANKLE, TOE AS A BOS

NECK DYNAMIC STABILITY

HEAD / EYE

POSTURAL TONEAXIS

Altered vestibular system

• Eyes

- connecting signals from the vestibular network

- helping modulation of postural tone

• VOR

• Neck collarboration

• Vestibular network of the eye and head

- axis에 대해 몸의 위치변화 감지- 머리의 조절

VESTIBULO-OCCULAR REFLEXES

Altered vestibular system

• Sub- occipital spine (atlas- axis complex)

• Trapezius, SCM

• Deep m.

Altered vestibular system

• Hyperextended and asymmetric posture-typical hypertonic pattern

• Insufficient sensorimotor experience

• Womb

- flexed posture, connective movement

• Neck m. (flexor part)

Altered Vestibular System Spastic Diplegia

• Hyperextended neck and eye

which leads extended body.

• Different head Location

mainly activate special

muscles group of extension

for maintain axis.

The eye

• Hyperextended neck, both eye not stable

- alteration of axis

- lead to change muscle, body alignment

• C1,C2 segment fixed

• Neutralization of altered vestibular system

- therapist correct the altered vestibular system, normal axis,

bring the eyes back to the middle

Altered Vestibular System Extended Child

The neck

• Muscles which locate around the neck are most important, which

is the basis for the postural control of human movement

• It works with vestibulospinal reflex, vestibulocollic reflex,

vestibuloocullar reflex

• For connecting with vestibular neural network, neck muscles are

composed of highest density of muscle spindle then other

muscles

The neck

• Spastic quadriplegia, dystonic athetosis

- Activated mainly extensor group

- Caused by dysfunction of the brain

- Hyperextended neck

- Hyperextended body d/t maintain the body axis

The neck

• Hyperextension inhibit C1-C2 complex movement-

altered vestibular system

Spastic diplegia

- Hyperextended neck

- Short neck,

- Disappearance of the SCM, Upper part of trapezius, C7

The neck

• Cannot function optimally

- lead to shortness of trapezius, deep capital

extensor m.

- Strong axis & information center의 기능을 할

수 없게 됨

The neck

• Head – sense its location & movement

• Neck- rotation, flexion, extension

• Vestibular information을 적절히 할 수가 없음

• C.P에서 postural tone 유지가 불가능하면 움직

일 수 없다

The neck

• Lack of rotation from cervical to thoracic

spine

- Unable scapular movement dissociation

- Unable shoulder joint movement

The neck

• Hemiplegia- low proximal tone

• Less movement on more affected side

• Hypertonus

• Poor body scheme

• Less weight bearing

The weakness of the neck

• Weak neck – proximal m. tone low

• Premature diplegia- insufficient postural tone, vestibular information

• Build up muscle of neck c proximal

• Activate two-eye watching

• Spinal rotation

The weakness of the neck

• Hyperkinetic athetosis

• Fluctuating postural tone

- poor head movement

• Neck brace - move axis

The weakness of the neck

• Hemiplegia

- Asymmetry in posture and movement

• SCM, upper trapezius

- activate weak & inactive m.

- postural tone appropriate and correct axis the

body

Connective movement of cervical, thoracic and lumbar spine

• Cervical spine rotation

- thoracic spine rotation

- lumbar spine rotation

• Vestibular network of CNS

- eye not midline, neck weakness

- low proximal tone

- poor connect movement of the spine

Connective movement of cervical, thoracic and lumbar spine

• Diplegia

- connective movement difficult

• Dissociated movement of the scapular

d/t especially poor neck movement

- because hyperextension or flexion

Power and speed: chin tuck

• Chin goes toward the spine – chin tuck

• Weak neck- power, speed not produce

• Hyperextension inhibit chin tuck

Axis keeper

• Neck, hand, gluteus maximus, ankle, toe

• Most strongest stabilizer – chin tuck

• Facial muscle – masseter

• Hand- pushing, pulling

• Gluteus maximus- sever as posture of extension

Axis keeper

• Landau reaction

- gluteus maximus strongly contract

• Upright sitting- highest head position, pelvic ant. Tilting

• In standing – maintaining axis from top to bottom

Axis keeper

• Ankle, toe - strongly contribute

BOS bipedal stance, dynamic movement

• Head is suddenly displaced or lose correct

head alignment

- running, ballet

Axis keeper

• Head is weak or altered vestibular

system

- all axis keeper will weaken or disappear

Proximal dynamic stability

• Proximal, neck dynamic stability

- Stabilization body for distal part movement

- Stabilization of rib cage

• Start to postural tone upon alertness (eye opening)

• Automatic activation

• Initiation of any kind of movement

Proximal dynamic stability

• Abdominalis, quadriceps, femoris, gluteals, diaphragm

• Proximal, pelvis conversely

- 3-dimensional pelvic movement

• Neural signal from the CNS

• Neuromuscular junction

• Enough number of muscle fiber

• Thus, activation and building up proximal m. are very

important

Proximal dynamic stability

• 3-dimensional pelvic movement

- Forward, backward, diagonal

• Crawl – one leg flexion, other leg extension

• Greater flexion – opposite greater extension

Proximal dynamic stability

• If weak- not generate postural tone

• Inactive trunk, muscle tone extensor

• Neck proximal stability – distal part move

• Rib cage & pelvis – arm, leg appropriate movement

• Proximal – neck, pelvis, core muscle

Physiologic postural reflex response

• Head righting reaction

- 출생직후 출현

- 지면에 엎드려 눕히면 고개를 들어올리는 반응

- Landau 와 derotative righting reaction으로 통합

• Landau reaction

- 엎드린 상태에서 영아의 배를 손으로 받치고 들어올림.

- Neck extension, trunk extension

Physiologic postural reflex response

• Derotative righting reaction

1) Head on body righting reaction

- 머리를 한쪽으로 돌리면 어깨, 몸통, 골반, 다리가 그 방향

으로 돌아감.

2) Body on body righting reaction

- 다리를 한쪽으로 꼬아 옆으로 돌리면 골반, 몸통, 어깨관절,

상지 순으로 꼬인 몸을 푼다.

• Optical righting reaction

- 몸을 한쪽으로 기울였을 때, 고개를 똑바로 위치하려고 하는

반응

Physiologic postural reflex response

• Labyrinthine righting reaction

- 눈을 가리고 몸을 한쪽으로 기울이면 전정기관

의 수용체가 자극

→ 목 주위 귺육의 귺 긴장도가 변함.

→ 고개를 똑바로 정위 자세로 위치

Physiologic postural reflex response

• Equilibrium reaction (평형 반응)

- 무게 중심이 몸의 중심에서 벗어났을 때 몸의 중심의 안정성을 다시 확보

ex) 앉은 자세에서 팔을 뻗어 물건을 잡으려 할 때

- Sitting, standing

• Protective reaction

- 무게중심의 이동이 너무 빠르고, 너무 커서 무게 중심을 유지하여 안정성

을 회복할 수 없을 때

ex) Parachute reaction

Thank You for Your Attention.