Lecture 7: Musculoskeletal Development Across the Lifespan Flashcards
Skeletal , muscle tissue, limb buds = what week
5
Limb movements = what week
8th
Kick legs, turning feet, bending wrist, turn heading head, opening mouth, and swallowing = what month
3rd month
Thumb sucking = what month
4th
Infancy has what type fibers primarily
Type 1 (slow twitch)
What is sarcopenia?
Decresed muscle mass
note infants have this
How much does muscle mass decrease after age 30
3-8%
note this number increases after 60
Neurmuscular alternations include a decrease in the nervous firing rate to muscle, the number of motor neurons, and the regenerative abilities of the nervous tissue
Connective tissue = dense ordinary connective tissue: regular or irregular
Do tendons have a regular or iregular arrangement?
Connective tissue that surrounds bones, muscles, heart is regular or iregular?
1 = regular
2 = irregular
Where is cartilage primarily found?
Articulating joints
Clavicle, manduble, and facial, cranial flat bones (irregular bones primarily) ossify how?
Intramembranous ossification
Deposition of bone on a cartilaginous model, limb bud, or outgrowth
Endochondral ossification
more long bone
Primarily ossification center that grows outward in the middle
Secondary in the ends of the bones that grow inward
* dont fully meet till ~18
Epiphyseal plates: allow the bone to grow until adult stature is attained
When is almost all bone growht done by?
18 (boys earlier than girls)
where would you guess you see bone fractions more older or younger?
Older: osteoblast activity decrease and osteoclast activity increases
Children have more cartilage so can absorb force/wt more
Result of joint mobility and the extensibility of soft tissues that cross the joint
Flexibility
What is physiologic flexion?
Wanting to be in flexion more as a baby
* becuse they were crunched up in utero
When do you see physiological flexion?
In both infants and older adults
old adults because age related changes at the cellular level compromise repair/function
KNOW: Babies typically have more ROM because they don’t have as much ossification (all the bones havent fully come together yet) and they’re already in ltos of physiological flexion
KNOW: Pre mature babies are bronw w/o physiological flexion (dont have to fit)
Breech
coming out feet first
* not optimal for dilvery
No children have much more DF than adults
Infants have how many bones
adults
~300 (hard to tell because some havent fully ossified and others have at different times)
206
Head bigger in babies torso smaller
* eyes don’t really change in size
KNOW: Fontanelles are there so the skull can fit through the birth canal
Heart takes up much more of thoracic cavity in children
KNOW: Posture starts at physicalgical flexion and end with it
starts curving around the time they start sitting ~6 months
KNOW: variability is a crucial element of motor development
* Allowing adaptability to the demands of a task and contextual aspects of the environment
Essentially everyone develops differently so we need have variability in what we do and how poeple do specific movements because not everyone is the same
* we all stand up and sit down a zillion different times and our body picks the patterns that are best for us
also doing tasks in varying environments
What is Sarcopena?
* causes what in older adults?
Decreased muscle mass that leads to decerased strength
* Slowing of contractile properties
* muscle loss can be accelerated by disease/medications
* Major cause of disability and frailty in older adults
KNOW: ligaments and tendons affected by surronding sturcutres
* Can be come stiff, lose elasticity, and decreased tensile strength
Tensile strength: Tension
* The maximum amount of stress a materal can withstand before breaking when it is pulled/stretched
What muscle fibers are mo affected in muscle loss type 1 or 2
type 2
KNOW: muscle fibers are replaced by fat
* Not due to being obese or sedentary lifestyle
* Muscle loss is going to happen no matter what and the body needs to fill its gaps and uses adipose tissue
Metabolic changes that contribute to sarcopnia: (5)
1) Increased insulin resistance (decerases the amount of GH in body)
2) decreased GH and insulin like GH (when osteoblasts are not being stimulated)
3) Decrease estorgen/testosterone (aids in production of GH)
4) Vitamin D deficiency
5) Increased parathyroid hormone (Increases Ca2+ which increases osteoclastic activity)
How can sarcopenia be reversed?
With high-intensity progressive resistive EX
* Just make sure dosing is correct (most commonly PT’s underdose older individuals)
KNOW: other causes of muscle loss
* Diabetes (insulin resistance)
* Metabolic syndrome (insulin resistance)
* COPD - O2 exchange affected
* Cancer
* CHF - O2 exchange affected
* Arthritits
* Kidney Disease - O2 exchange affected
* Stroke
* Parkinson’s Disease
With older adults: bone and cartilage are decreased due to
Decreased osteoblastic activity (build)
* Causes decrease in bone mass/density
Decreased tensile strength of bone (more susceptable to fx because of this)
* More susceptible to fractures (women > men due to decreased GH/estogen)
*Long term corticosteriod use
* Impair bone healing
KNOW: W/ age cartilage dehydrates, becomes stiffer, and thins in weightbearing areas if we dont allow the weight bearing to happen
Decreased collagen production
If you under dose it will not stimulate enough osteoblastic activity, and if you overdose it can blunt osteoblastic activity as well.
KNOW: These myofibrils empty w/ age, leaving only the structure around them (looks like a honey comb)
* This causes a decrease in structure
You are going to have increased structural protein cross-linkages
* These are those bridges that go from myofibril to myofibril
* However, when you decrease the total # of overall fibers these linkages continue to grow and get longer to connect the reminaing fibers
* These are not as strong or as felxibile as a muscle fiber (its stiffer)
* Same concept as osteoprosis where you’re decrease the density of overall muscle and its weaker
Decreased proteoglyan size
Fragmented collagen
Age releated changes in connective tissue
Cellular
* decreased proliferation
* Alterd control of apoptosis
* Decreased response to growth factors
* Altered response to loading (dont have the same amount of osteoblastic activity)
Deeper structures = more normal collagen
Disorganized collagen = more superficial collagen
Age releated changes in connective tissue
Connective tissue strucutre:
* Increased stiffness
* Decreased h20 content
* Decreased strength
* decreased cross-sectional area and volume
All this stuff also happens to IV discs
Is osteoprosis a MSK pathology?
* What is it and what is it due to
No! its a metabolic disorder due to lack of vitamin D
* Vitamin D needed to synthesize Ca2+
Increased osteoclast and decreased osteoblastic activity
decreased load absorption
Impaired neuromusclar function as well
* Nerves not firing/regenerating as well as they were before which means they might not be innervating the msucles are well as they did before (turns into muscle problem)
Preceeded by osteopenia
4 places where fx is common in older adults
1) Head of femur
2) Pelvis
3) Distal radius
4) vertebrae
Cartilage is how much water?
60-80%
Cartilage: w/ age
1) decreased proliferation of chondroblasts (decreased strength / volume)
2) Altered apoptosis regulation (programmed cell death)
3) Altered response to loading
4) Increase in collagen fibers increase stiffness (less water in cartilage tissue - remember cartilage is 60-80% H2O)
W/ age: IV discs
decreased size
* decreased h2O content
* Can cause DDD due to decreased disc height
Nucleus becomes more fibrous (decreased flexibility / elasticity)
Annulus becomes less organized - more fragile to tensile strengths
Common joint replacements
TKA:
* Most common
* 4.2 adults over 50 have this
* females > males
* ~40% are 50-69 when its done
THA (find percautions)
* Anterior approach
* Lateral approach
* Posterior approach
Total shoulder / reverse
* reverse best for a completely fucked rotator cuff ANDDDD no signs of arthritits (normally more truamatic)
Frality guidelines
Need 3/5 for frality 2/5 for pre
