MSK Changes

Question 1

Perichondrium

Answer 1

Diffuses nutrients to cartilage

Question 2

ECM

Answer 2

Water
Proteoglycans
Collagen

Question 3

Interstitial cartilage growth

Answer 3

Increased internal mass

Question 4

Appositional cartilage growth

Answer 4

New surface

Joints don’t have this :(

Question 5

Cartilage: over time

Answer 5

Thinning
Atrophy
Decreased water content
Decreased number of chondrocytes
Rougher surface = decreased joint efficiency

Question 6

Bony maturity

Answer 6

20

Endochondral ossification except for clavicle, mandible, skull

Question 7

Interstitial bony growth

Answer 7

Growth in length

Proliferation on diaphyseal end

Question 8

Appositional bony growth

Answer 8

Growth in diameter

Most rapid during prenatal period

Question 9

Bony rotational changes

Answer 9

Newborn - peak varum
1-2 years - peak straight
2-4 years - peak valgum
Approx 16 - adult

Question 10

Anteversion

Answer 10

Decreases over time
Newborn 25-30
Adult 10-15

Question 11

Joint formation

Answer 11

6-8 wks gestation

Question 12

Growing pains

Answer 12

4-12 years
Late evening or night, resolve by am
Mostly LE
Cause? Mm grows slower than bone

Question 13

None loss over time

Answer 13

Women > men

Estrogen slows bone resorption
Testosterone enhances Ca++ resorption

Pre-menopausal = 1% loss per year
Post-menopausal = 3-4% loss per year

Question 14

Scoliosis

Answer 14

Girls progress more
Measured by Cobb angle
Named for convex side (where it points)

Treatment
0-20 monitor
20-40 bracing and exercise
>40 surgical stabilization

Goal = halt the progression!!!

Question 15

Apophysitis

Answer 15

Osgood Schlatters - tibial tubercle protrudes

Sever’s disease - when heel protrudes

Question 16

Bone maturity

Answer 16

Growth plates complete by 25
Vertebra close last
Remodeling continues

Question 17

Adult bony concerns

Answer 17

Annulus fibrosis increasingly fibrotic
Nucleus pulposus loses volume

IV DISCS = fibrocartilage

Question 18

Mm growth

Answer 18

Prenatal and 1st year- increase in number

After first year - increase in size

Question 19

Adult typical ratios

Answer 19

Intercostals 2 mos: breathing
Diaphragm 7 mos: more time upright
Soleus 10 mos: standing, creeping, cruising, walking

Question 20

Adult speed

Answer 20

10 years

Question 21

Boys

Answer 21

Longer growth period and sharper acceleration in growth

Question 22

Strength gains

Answer 22

Related to growth curve
Genetic factors
Boys > girls

Question 23

Child mm training

Answer 23

No notable change in mass
Neural adaptations may play larger role
Questionable efficacy

Question 24

Strength over lifespan

Answer 24

Children - boys > girls
Adolescents - mass before strength, stretching important
Adults - peaks in 30s, declines in 50s

Question 25

Trends in declining strength

Answer 25

Slightly less decline in UE than LE
Strength and speed affected
Women demonstrate earlier declines

Question 26

Sarcopenia

Answer 26

Mm wasting
6-15% older adults
*activity level
*hormone level
*loss of contractile properties

Question 27

Motor neuron remodeling

Answer 27

Decreased number
Many type II fibers INN by slow twitch fibers
Motor unit firing slows

Question 28

Other adulthood changes

Answer 28

Protein synthesis declines
Connective tissue increases (cross-linking)
Lost mm fibers replaced c fat and collagen

Question 29

Hyaline/articular cartilage

Answer 29

Most rigid and most common
Vast majority of fetal skeleton made of this
Most water content - 80%