Musculoskeletal Development and Gait Biomechanics

Question 1

When does musculoskeletal development occur during the prenatal period?

Answer 1

Occurs during the embryonic period (2nd-8th weeks post conception)

Question 2

What are the three parts of the trilaminar embryo and what do they become?

Answer 2

1) Ectoderm- skin and nervous system
2) Mesoderm- Muscle and CT
3) Endoderm- Organs

Question 3

What does the mesenchymal cells transform to? And what time period does it occur?

Answer 3

Limb buds

Differentiates into carriage at week 3-4

Question 4

When does joint formation begin and end?

Answer 4

Begins- during week 6-8

Ends- early childhood

Question 5

Cartilaginous skeleton occurs rapidly and is completed in how many months?

Answer 5

3

Question 6

Where does primary ossifications of long bones begin?

Answer 6

The diaphysis of the long bones

Question 7

When does primary ossification start and end?

Answer 7

Week 8 through the 3rd trimester

Question 8

Where does secondary ossification of the long bones begin?

Answer 8

Begins in the epiphysis of the long bones

Question 9

When does secondary ossification begin and end?

Answer 9

Perinatally through 20 years old

Question 10

What are the three types of bone growth?

Answer 10

Epiphyseal: grows in length
Longitudinal: occurs at epiphyseal plate til 20 y.o.
Appositional: Growth in density

Question 11

What is appositional growth?

Answer 11

Accumulation of new bone on the bone surface (i.e. the greater trochanter)

Question 12

What stimulates appositional growth?

Answer 12

Compressive forces; increased WB results in increased thickness and density of the shaft of the bones

Question 13

What is normal alignment of the spine?

Answer 13

Kyphosis present at birth, spinal extension developed by 5th month (with swimming), lordosis begins developing by 7 months (indep. sitting and pull to stand)

Question 14

Abnormal alignment of the spine is?

Answer 14

1. Kyphosis persisting through 1st year- decreased thoracic extension seen with decreased scapular/thoracic mobility, tight pecs, decreased scapular ROM.
2. Results in impaired sitting, UE function, respiration.
3. Scoliosis- lateral curvature of spine due to asymmetry of mm pull (neurological or idiopathic)

Question 15

When assessing the spine what are you looking for?

Answer 15

Scoliosis- rib hump
Scoliosis is named for the convexity of curve
Observation of spinal alignment in bending forward and ambulation

Question 16

At birth the alignment of the hip looks like?

Answer 16

Swallow acetabulum, depth increases unit 8 years old when head of femur has full coverage

Question 17

What do the compressive forces of the femoral head result in?

Answer 17

Formation of the hip joint

Question 18

Where is maximum congruity in the hip?

Answer 18

During hip flexion

Question 19

Give the position that is greatest for acetabular development.

Answer 19

Frog leg position

Question 20

Give the angle of inclinations for birth, adult, and atypical.

Answer 20

Birth: 145 (valga)
Adult: 125 (normal) {ADD plays a big role here}
Atypical: <125 (vara)

Question 21

What is the definition of “version”?

Answer 21

Angular difference between the transcondylar axis of the knee and the axis of the femoral neck.

Question 22

Give the degrees for normal ante version.

Answer 22

Normal: 5-16 degrees anteversion

Question 23

The 5-16 degrees of anteversion allows for what?

Answer 23

Allows for the foot to be pointed straight ahead with the femur sitting in the acetabulum

Question 24

What is anteversion and what could it cause?

Answer 24

Turning of the femoral head anterior to the frontal plane.
Excessive Anteversion: Can cause IR of femur to put femoral head in acetabulum and cause toe-in. (The W-sit is problematic here)

Question 25

What is retroversion and what could it cause?

Answer 25

Turning of the femoral head posterior to the frontal plane | Excessive Retroversion: Femur must ER to achieve joint congruency-causing toe out

Question 26

When assessing hip rotation how should you assess and what is normal for infants and adults?

Answer 26

Assess in prone Infants: IR>ER Childhood IR=ER Adults: ER>IR

Question 27

Hip version is assessed how?

Answer 27

Assessed during gait

Question 28

Give the degrees for hip flexion at birth, 1 y/o and 5 y/o.

Answer 28

Birth: 30-50 degrees contracture at birth 1 year: 10-20 degrees contracture 5 year: 0 degrees contracture

Question 29

Normal knee alignment is considered what?

Answer 29

Flexion contracture 20-30 at birth and 1-2 years is 0 degrees

Question 30

Give what is considered abnormal alignment of the knee.

Answer 30

Decreased quad activity and increased HS activity due to persistent knee flexion contracture and compensatory problems of crouched gait.

Question 31

The knee is assessed by what angle and how?

Answer 31

Popliteal angle 1) Supine, hip and knee flexed to 90 2) Extend knee until resistance, toni at knee

Question 32

When looking at knee alignment and assessment what two variations of tibiofemoral angle might you see?

Answer 32

``` Genu varum (bow legged) Genu valgum (knock kneed) ```

Question 33

Give the degrees for tibiofemoral angles at birth, 3, 3-6, 6+, and adult.

Answer 33

``` Birth: ~17 degrees genu varum 3 years: 0-12 degrees genu valgum 3-6 years: 5-12 degrees genu valgum 6+ years: 5-7 degrees genu valgum Adult: 5-7 degrees genu valgum ```

Question 34

What is considered normal DF for Birth, 1, 4, 5, and adult?

Answer 34

``` Birth: 70-80 degrees 1 year: 25-45 degrees 4 year: 20-60 degrees 5 year: 10-20 degrees Adult: 8-15 degrees ```

Question 35

What are the normal values for PF for birth, 1, and 5 years?

Answer 35

Birth: 15-30 degrees 1 year: 45 degrees 5 year: 45+ (full)

Question 36

At birth what are the values for neutral STJ and forefoot varus?

Answer 36

STJ: 10 degrees varus Varus: 12-15 degrees

Question 37

When does eversion stop decreasing?

Answer 37

at age 7

Question 38

As an adult what is STJ and forefoot varus?

Answer 38

STJ: 2-3 degrees varus Varus: 0-2 degrees

Question 39

What are the determinants of walking in the development of gait?

Answer 39

``` Single limb Stance Walking velocity Cadence Step length Ratio of pelvic span to ankle span (wide based gait) ```

Question 40

During birth to 9 months how does gait develop?

Answer 40

1) Working on antigravity movements 2) Antigravity strength gained in first 9 months essential for indep. ambulation 3) Flexion contracture at hip 4) Physiological varus at tibiofemoral angle

Question 41

What are the major characteristics of a 9-15 month olds walking?

Answer 41

1. Wide BoS 2. Hip ABD, flexion, and ER 3. Knee flexion and varus 4. Full foot initial contact in PF, heel everted 5. Short stride, increased cadence 6. Relative foot drop in swing 7. High Guard

Question 42

Discuss some of the characteristics of balance and strength during the gait of 9-15 month olds.

Answer 42

1. Balance comes M/L first and then A/P 2. Hip strength is inadequate to control gravitational forces 3. Gait similar to an adult walking on ice 4. Postural alignments made by movements of entire body 5. Initial patterns similar to kicking in early infancy 6. Co-activation of antagonistic muscles 7. Limiting factor: extensor strength (not pattern-generating abilities) 8. CoM is closer to head/upper trunk 9. Fat:muscle mass still high- therefore relative weakness

Question 43

Describe what is happening during the early stages of walking with the UE and trunk.

Answer 43

UE: High guard and non reciprocal arm swing Trunk: Forward, lateral shift to advance

Question 44

From the pelvis to the ankle what would an early walker look like?

Answer 44

Pelvis: Ant. tilt, hip hike to clear floor, excessive rotation to increase step length Hip: Stance Phase-Excessive flexion (contracture and weakness) Knee: Stance Phase-Excessive flexion Ankle: Initial Contact- foot flat or little PF Swing Phase- PF Step direction: Taken on diagonal increasing BoS

Question 45

When a child is 18-24 months old there is a change in their UE movements while walking. What is it?

Answer 45

High guard is decreasing and reciprocal arm swing begins

Question 46

What is happening in the LE during gait when a child is 18-24 months old?

Answer 46

Hip: more extension in stance Knee: immature flexion wave; more extension at IC Ankle: Immature heel strike begins Feet: Narrower BoS

Question 47

As velocity increases in gait a child will do what to keep their balance?

Answer 47

They will revert back to the 12 month pattern to help them keep their balance

Question 48

Discuss the the cadence, step length, and CoM for a child 18-24 months old.

Answer 48

Cadence: Increased compared to adult gait Step length: decreased compared to adult CoM: moves distally (which increases stability)

Question 49

Walking experience is important for what during the 18-24 month period?

Answer 49

New balance and postural control strategies

Question 50

What part of gait become amore stable during this time?

Answer 50

Single leg stance

Question 51

If a child's gait begins to smooth out during this time what can you assume is occurring?

Answer 51

A decrease of co-contraction of antagonistic muscles.

Question 52

The LE of a 2+ year old are changing; describe those changes in the pelvis, knee, and ankle.

Answer 52

Pelvis: excess rotation still present Knee: Full extension in stance is immature and stance knee flexion remains until 3 years old Ankle: Heel-toe doesn't begin tip 3 y/o

Question 53

What are some of the major characteristics of a 3-3.5 year old walking?

Answer 53

``` Genu valgus Femoral anteversion is decreasing CoM near Lumbar spine Heel eversion decreasing Heel strike consistent with knee flex of opp. leg Reciprocal arm swing ```

Question 54

A 6-7 year old has gone through changes in their walking from a 3-3.5 year old. Describe some of those changes.

Answer 54

Stability by 4-6 y/o Fully mature by 7 y/o Heel position is in neutral CoM is at 3rd lumbar vertebra (sacral as adult)