Motor Development

Controlled Mobility

Characterized by the ability to move in and out of posture, to make postural transitions, to weight shift in posture

Hypertonia

Excessive muscle tone that prevents movement; spasticity and rigidity

Hypotonia

Low muscle tone that makes movement against gravity difficult or challenging

Internal stability

Internal control mechanisms to maintain posture without need of positional stability

Motor Control

The ability to regulate and monitor the motions of muscle groups to work together in order to efficiently and successfully perform movements

Primitive reflexes

Involuntary movements observed in young infants typically triggered by some external stimulus

What happens if primitive reflexes don’t integrate?

The motor development will be stunted, so reflexes can’t be replaced with purposeful, controlled movements

Positional Stability

Use of body to provide support until internal stability \n is gained

Protective extension

straightening of the arm to catch one’s balance when the body is moved quickly

Reciprocal

alternating but coordinated body movements(taking steps)

Righting reactions

Orientation of head to body with attempts to keep head in alignment with body during weight shifts

Skill

Combination of mobility, stability, and controlled mobility in relation to speed, timing, etc for efficient performance of desired activity

Structural stability

soft tissue tightness resulting from in utero positioning

Adult motor control

ability to move within movement patterns and to maintain posture against gravity

Development of which antigravity control precedes the other?

Extensor over flexor

For muscles to engage in antigravity control?

They must first be elongated

In utero neonate is completely flexed so…?

extensors are elongated and are prepared for antigravity function

When will we see some indications of antigravity lexor control?

Around 4 months, although it will still be lagging

By 6 months flexors and extensors

should have balanced response between them

Development proceeds…?

cephalocaudal, proximal to distal and from gross to fine movement

Random, spontaneous, non-purposeful movements

newborn can lift and turn head momentarily in prone and demonstrate non-purposeful kicking of lower extremities in prone and supine

Bilateral, symmetrical movements

By 3 months

bilateral symmetrical control of extensor muscles of head and neck in prone

Supine by 4 months

Alternate reciprocal movements

3.5 months

Ex. one SCM muscle is contracting while the other is relaxing so baby in prone can lift and turn head to one side

Unilateral Symmetrical movements

The flexor and extensor muscles on the same side of the work together to produce lateral movement of the head and or trunk. Lateral tilting of the head at about 4 months of age

Diagonal reciprocal movements

Most advanced

Elongation on weighted and shortening on unweighted side

The trunk displays rotation, equilibrium responses and normal responses to loading and unloading.

Stability is the ability to maintain

a posture once it has been assumed

Stability is characterized by the

patterns of co-innervation in the CNS and resultant co-contraction of agonists and antagonists around the joint

Where is the infant center of gravity?

At the nipple level T4

Where does the COG develop eventually

As the child grows the COG descends until it reaches its adult level which is in the lower lumbar area

When does COG shift

as movement within a posture occurs and must be controlled to keep it within the base of support or to bring it back within the base of support.

If COG goes too far out

When the COG get too far out of the base of support, it generally results in a fall

Point of stability

point in a posture toward which the weight is shifted. \n “anchor” of the posture around which movement occurs. \n It is the least moveable point in the posture

as we move away from the point of stability

greater ranges of movement are possible

Relationship between mandible and maxilla

the appropriate relationship is not achieved, the individual will demonstrate an underbite, overbite, or crossbite

Improper development of rib cage

it can result in a variety of problems including impaired patterns of respiration, sound production, and speech.

Relationship of femur to acetabulum

60 degrees of femoral ante-version

femoral head rotated forward and out

As weight bearing and exertion of muscle pull across the bone, the femur will

realign itself with the acetabulum and the internal torsion will unwind, so that the adult \n relationship of 8 degrees if femoral anteversion and torsion will occur

Failure of femur and acetabulum development

excessive toeing in or toeing out, and unstable hip, and impaired stability of the trunk

Bow-leggedness resolves by

1.5 yrs of age

What happens in LE for delayed children

delayed in normal alignment

Muscle tone

resistance to passive stretch

degree of stiffness of muscle

Compliance

measure of tissue’s ability to yield pressure or force without disruption

Lack of compliance

occurs in spasticity, rigidity

Presence of scar tissue or contracture

will affect the ability of the joint/muscle to move in the expected fashion and will result in distorted posture or movement

Infant tissue compliance

\n Normal infant has a slight decrease in tissue compliance due to flexor tightness. This will be \n resolved within the first few months of life

Four stages of normal motor development

mobility, stability, controlled mobility, skill

If patient has normal mobility, normal stability, and normal controlled mobility;

skill will develop without much difficulty, other are more likely to be the problem

Normal postural reflex mechanism

Protective extension, righting reactions, equilibrium reactions

Refinement age range

end of 5 month to beginning of 6 to 5 years of age