Body Systems of the First Year

Question 1

sway postural response strategies

Answer 1

ankle
hip
stepping

Question 2

ANKLE STRATEGY

Answer 2

small perturbations
foot fully supported

Muscle activity begins distally

• LOB forward
• LOB backward

Question 3

HIP STRATEGY

Answer 3

large perturbations
foot not fully supported

Muscle activity begins proximally

• LOB forward
• LOB backward

Question 4

stepping strategy

Answer 4

perturbation too large to recover without protective step

Question 5

postural response strategies depend on

Answer 5

Speed of perturbation

Degree of displacement (force)

Developmental stage
-Young children may not use best

4-6 yo: varying strategies

7-10 yo: Consistent ankle strategy, more timely

Question 6

BALANCE

Answer 6

ability to maintain equilibrium

Question 7

STABILITY

Answer 7

ability to resist movement disruptions

Question 8

increase stability

Answer 8

Increase base of support
Lower center of gravity
Keep COG within BOS

Question 9

↑ stability

Answer 9

↑ balance = ↓ mobility

Question 10

musculoskeletal system year 1

Answer 10

Rapid bone growth & modeling

Factors affecting bone growth:
Genetics
Nutrition
General health status
Hormonal levels
Physical activity

Question 11

muscle year 1

Answer 11

Growth of skeletal fibers

• Increase in number of muscle fibers
• Increase in muscle fiber size

Question 12

postural (spine) alignment year 1

Answer 12

Cervical lordosis
-More evident with improved head control

Lumbar lordosis
-More pronounced with sitting and anti-gravity skills

Question 13

hip alignment year 1

Answer 13

Development of the Femur

Newborns: start in retroversion

Children: more anteversion than adults

Adults: Progress to slight anteversion

Question 14

angle of inclination

Answer 14

Starts out straight then angles with weight bearing
Angle decreases with typical WB
(B) Obesity in childhood → Coxa vara → early onset OA
(C) Decreased WB in childhood → Coxa valga → subluxation/ dislocation

Question 15

acetabular index

Answer 15

More coverage of femoral head

Larger angle indicates ↓ WB

Question 16

knee alignment

Answer 16

Femur to Tibia relationship:
Genu varum to neutral

Increased walking & W/B:
Progresses to genu valgus

Typical adults:
Slight genu vagus

Question 17

foot alignment

Answer 17

Newborn
Calcaneal varus →
slowly progress to neutral

Question 18

sequence of ossification of the tarsal bones

Answer 18

metatarsals and phalanges: 9-12 weeks
calcaneus: 4-7 months
talus: 6 months
cuboid: around birth
lateral cuneiform: during year 1
medial cuneiform: during year 2
intermediate cuneiform: during year 3
navicular: during year 3 after intermediate cuneiform

Question 19

standing 1-2 years old

Answer 19

When a child begins to stand
-Physiologicalflat foot
-With hindfoot valgus 
-Due toflexibilityof thejoints
Increased subcutaneous fat
-Fat pad
Pediatric feet 
-Generally flexible 
-Hypermobile

Question 20

feet 3-5 years

Answer 20

3 yo: Navicular ossification
3 – 4 yo:
Flexibility decreases
Subcutaneous fatdecreases
Medial longitudinal arch begins to form
4 – 5 yo : Longitudinal arch = adult-like shape
it is normal for young children to have flat feet

Question 21

nervous system year 1

Answer 21

Brain Growth

• At birth, 25% of its adult -weight
• At one year, 60% of its adult weight

Critical brain growth
-Between 3 months & 2 years of age

Early brain growth coincides:

• Cognitive development
• Language development

Question 22

myelination year 1

Answer 22

Myelination of CNS

• Continues into young adulthood
• Slows considerably after 2 yo

Myelination of PNS

• Mostly complete at birth
• Immediate access to environmental sensory info

Question 23

cardiovascular system year 1

Answer 23

Heart size increases

Mature muscle fibers contract with more force

Heart muscle vascularization increases

Arteries & veins increase in size

Question 24

respiratory system year 1

Answer 24

At birth: fraction of total alveoli present
New alveoli develop until 8-10 yo

Airways increase in length & diameter

Bronchioles & alveoli become stronger/more efficient

Newborns: highest respiratory rates

Infants & young children
Higher energy cost of respiration than adults
Less efficient coordination of respiratory muscles

Question 25

respiratory system infants and young children

Answer 25

Barrel chest with flared ribs Abdominals are weaker Less resistance to pull of diaphragm Increased risk of infection & atelectasis

Question 26

hallmark motor milestones

Answer 26

``` 4-6 mo: Rolls prone to supine 4-6 mo: Rolls supine to prone 6-7 mo: Sits alone 8-10 mo: Creeps on hands & knees 12 mo: Walks alone ```

Question 27

cephalocaudal development

Answer 27

First quarter of first year of life Control of head in all positions in space Second quarter of first year of life Control of arms and upper trunk Third quarter of first year of life Control of lower trunk and pelvis in the upright position Fourth quarter of first year of life Control and mobility of the lower parts of the legs in upright stance

Question 28

functional head control

Answer 28

Birth Vertical head position only sustainable for 1-2 sec. Can turn head to clear airway 3 months Synergistic control of neck flexors and extensors Stable vertical head position Able to turn head freely 4 months Organized eye-head-hand control seen in prone Lack of/decreased head control

Question 29

upright trunk control

Answer 29

``` 4 months Prone Extending the head and trunk Legs and pelvis are load-bearing Caudal weight shift ``` 6 months Independent sitting with object manipulation achieved

Question 30

lower trunk control in the upright position

Answer 30

Control of lower trunk and pelvis allows for: 7 mo. – Crawling & creeping 8 mo – Pulling to stand 8 mo – Moving in and out of quadruped and sitting Freedom from midline symmetry Rotational abilities

Question 31

fine lower extremity control

Answer 31

Control of trunk and pelvis Reciprocal lower extremity movement 8-9 mo – Creeping 9-11 mo – Supported walking 11 – 15 mo – Independent walking

Question 32

developmental sequence

Answer 32

Follows predictable sequence/pattern Universality Predictable patterns Variability Individual differences Cultural e.g. Establishing PT plan of care